Intel Stratix 10 General Purpose I/O User Guide

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UG-S10GPIO | 2020.11.13

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Updated for:
Intel® Quartus® Prime Design Suite 20.3

1. Intel Stratix 10 I/O Overview

The Intel^® Stratix^® 10 general purpose I/O (GPIO) system consists of the I/O elements (IOE) and the GPIO Intel^® FPGA IP.

The IOEs contain bidirectional I/O buffers and I/O registers located in LVDS I/O banks.
The GPIO IP core supports the GPIO components and features, including double data rate I/O (DDIO), delay chains, I/O buffers, control signals, and clocking.
Two of the LVDS I/O banks are shared with the Secure Device Manager (SDM).
For devices with Hard Processor System (HPS), three of the LVDS I/O banks are shared with the HPS SDRAM interface.
The 3 V I/O banks do not feature I/O registers and DDIOs.
The 3.3 V I/O bank is available in the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices.

1.1. Intel Stratix 10 I/O and Differential I/O Buffers

The general purpose I/Os (GPIOs) consist of the following I/O banks:

LVDS I/O bank—supports differential and single-ended I/O standards up to 1.8 V. The LVDS I/O pins form pairs of true differential LVDS channels. Each pair supports a parallel input/output termination between the two pins. You can use each LVDS channel as transmitter only or receiver only. Each LVDS channel supports transmit SERDES and receive SERDES with DPA circuitry. For example, if you use 30 channels of the available 72 channels as transmitters, you can use the remaining 42 channels as receivers.
3 V I/O bank—supports single-ended LVCMOS and LVTTL I/O standards up to 3.0 V. In Intel^® Stratix^® 10 devices, each 3 V I/O bank supports only two output enables (OE) for its eight single-ended I/Os. Single-ended I/Os within this I/O bank support all programmable I/O element (IOE) features except:
- Programmable pre-emphasis
- R_D on-chip termination (OCT)
- Calibrated R_S and R_T OCT
- Internal V_REF generation
- Dynamic OCT
3.3 V I/O bank—supports single-ended LVCMOS and LVTTL I/O standards at 3.3 V and 3.0 V. This feature is available only in the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices. The 3.3 V I/O buffer is unidirectional. You can configure the I/O pins in the bank in preset groups of eight pins—as all input pins or all output pins. The bank supports the following features:
- As input—programmable pull up resistor
- As output—programmable current strength

Note: The 3 V I/O banks in Intel^® Stratix^® 10 devices do not support the DDIO feature of the GPIO IP core. Bypass the DDIO if you use an I/O standard supported only by 3 V I/O banks, such as 3.0 V LVCMOS. To bypass the DDIO feature, set the Register mode of the GPIO IP core to none.

Note: The 3 V I/O banks are located on the Intel^® Stratix^® 10 transceiver tiles. These banks are available only on the L-tile and H-tile transceiver tiles.

1.2. Intel Stratix 10 I/O Migration Support

In the following figures, the arrows indicate the migration paths. The devices included in each migration path are shaded.
If the line connects two different columns, you can migrate between different packages of the product lines. However, different ordering part number of the product lines may have different LE count, transceiver count, or HBM features.
To achieve the full I/O migration across product lines in the same migration path, restrict I/Os and transceivers usage to match the product line with the lowest I/O and transceiver counts.

Figure 1. Migration Capability Across Intel^® Stratix^® 10 GX and SX Product Lines—Preliminary

Figure 2. Migration Capability Across Intel^® Stratix^® 10 TX Product Lines—Preliminary

Figure 3. Migration Capability Across Intel^® Stratix^® 10 MX Product Lines—Preliminary

Figure 4. Migration Capability Across Intel^® Stratix^® 10 DX Product Lines—Preliminary

Note: To verify the pin migration compatibility, use the Pin Migration View window in the Intel^® Quartus^® Prime software Pin Planner.

2. Intel Stratix 10 I/O Architecture and Features

The I/O system of Intel^® Stratix^® 10 devices supports various I/O standards. In Intel^® Stratix^® 10 devices, the I/O pins are located in I/O banks. The I/O pins and I/O buffers have several programmable features.

The Intel^® Stratix^® 10 I/Os support the following features:

Single-ended, non-voltage-referenced, and voltage-referenced I/O standards
Low-voltage differential signaling (LVDS), RSDS, mini-LVDS, HSTL, HSUL, SSTL, and POD I/O standards
Serializer/deserializer (SERDES)
Programmable output current strength
Programmable slew rate
Programmable bus-hold
Programmable weak pull-up resistor
Programmable pre-emphasis for DDR4 and the LVDS output buffer
Programmable I/O delay
Programmable differential output voltage (V_OD)
Programmable open-drain output
On-chip series termination (R_S OCT) with and without calibration
On-chip parallel termination (R_T OCT)
On-chip differential termination (R_D OCT)
HSTL and SSTL input buffer with dynamic power down
Dynamic on-chip parallel termination for all I/O banks
Internally generated V_REF with DDR4 calibration

Note: The information in this chapter is applicable to all Intel^® Stratix^® 10 variants, unless noted otherwise.

2.1. I/O Standards and Voltage Levels in Intel Stratix 10 Devices

The Intel^® Stratix^® 10 device family consists of FPGA and SoC devices. The Intel^® Stratix^® 10 FPGA devices have only FPGA I/O buffers. The Intel^® Stratix^® 10 SoC devices have FPGA I/O and HPS I/O buffers. The HPS I/O buffers in Intel^® Stratix^® 10 SoC devices support different I/O standards than the FPGA I/O buffers.

2.1.1. Intel Stratix 10 I/O Standards Support

Table 1. Intel^® Stratix^® 10 Devices I/O Standards Support for FPGA I/O—Preliminary
I/O Standard	I/O Buffer Type Support			Application	Standard Support
I/O Standard	LVDS I/O	3 V I/O¹ ²	3.3 V I/O³	Application	Standard Support
3.3 V LVTTL/3.3 V LVCMOS	No	No	Yes	General purpose	JESD8-B
3.0 V LVTTL/3.0 V LVCMOS	No	Yes ⁴	Yes	General purpose	JESD8-B
2.5 V LVCMOS	No	Yes ⁵	No	General purpose	JESD8-5
1.8 V LVCMOS	Yes	Yes ⁵	No	General purpose	JESD8-7
1.5 V LVCMOS	Yes	Yes ⁵	No	General purpose	JESD8-11
1.2 V LVCMOS	Yes	Yes ⁵	No	General purpose	JESD8-12
SSTL-18 Class I and Class II	Yes	No	No	Flash interface	JESD8-15
SSTL-15 Class I and Class II	Yes	No	No	DDR3	—
SSTL-15	Yes	No	No	DDR3	JESD79-3D
SSTL-135	Yes	No	No	DDR3L	—
SSTL-125 ⁶	Yes	No	No	QDR-IV	—
SSTL-12	Yes	No	No	RLDRAM 3, QDR-IV	—
POD12	Yes	No	No	DDR4, QDR-IV	JESD8-24
1.8 V HSTL Class I and Class II	Yes	No	No	DDR II+, QDR II+, and RLDRAM 2	JESD8-6
1.5 V HSTL Class I and Class II	Yes	No	No	DDR II+, QDR II+, QDR II, and RLDRAM 2	JESD8-6
1.2 V HSTL Class I and Class II	Yes	No	No	QDR-IV, General purpose	JESD8-16A
HSUL-12	Yes	No	No	LPDDR2, LPDDR3	—
Differential SSTL-18 Class I and Class II	Yes	No	No	General purpose	JESD8-15
Differential SSTL-15 Class I and Class II	Yes	No	No	DDR3	—
Differential SSTL-15	Yes	No	No	DDR3	JESD79-3D
Differential SSTL-135	Yes	No	No	DDR3L	—
Differential SSTL-125⁶	Yes	No	No	General purpose	—
Differential SSTL-12	Yes	No	No	RLDRAM 3	—
Differential POD12	Yes	No	No	DDR4	JESD8-24
Differential 1.8 V HSTL Class I and Class II	Yes	No	No	DDR II+, QDR II+, and RLDRAM 2	JESD8-6
Differential 1.5 V HSTL Class I and Class II	Yes	No	No	DDR II+, QDR II+, QDR II, and RLDRAM 2	JESD8-6
Differential 1.2 V HSTL Class I and Class II	Yes	No	No	General purpose	JESD8-16A
Differential HSUL-12	Yes	No	No	LPDDR2, LPDDR3	—
LVDS ⁷	Yes	No	No	SGMII, SFI, SPI	ANSI/TIA/EIA-644
Mini-LVDS ⁷	Yes	No	No	SGMII, SFI, SPI	—
RSDS⁷	Yes	No	No	SGMII, SFI, SPI	—
LVPECL	Yes	No	No	SGMII, SFI, SPI	—

Note: To use the 1.2 V, 1.5 V, 1.8 V, 2.5, or 3.0 V I/O standards in the 3 V I/O bank, you must set the USE_AS_3V_GPIO assignment to the I/O pin. In the Intel^® Quartus^® Prime Settings File (.qsf), specify the following assignment: set_instance_assignment -name USE_AS_3V_GPIO ON -to <your pin name>

Table 2. Intel^® Stratix^® 10 SX Devices I/O Standards Support for HPS I/O—Preliminary
I/O Standard	Application	Standard Support
1.8 V LVCMOS	General purpose	JESD8-7

¹ Available only on L-tile and H-tile transceiver tiles.

² When a transceiver tile is powered down, the tile's 3 V I/O bank is not available.

³ Available only on I/O bank 3C of the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices.

⁴ For the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices, the Intel^® Quartus^® Prime software automatically implements the 3 V I/O standard using I/O bank 3C. For H-tile and L-tile devices, you must set the USE_AS_3V_GPIO Intel^® Quartus^® Prime assignment to the pin.

⁵ You must set the USE_AS_3V_GPIO Intel^® Quartus^® Prime assignment to the pin.

⁶ Even though the Intel^® Stratix^® 10 I/O buffers support various I/O standards for memory application, Intel validates and support only IPs for memory interfaces listed in Performance Support Summary, Intel^® Stratix^® 10 External Memory Interfaces User Guide.

⁷ Supported only on dedicated clock pin in I/O banks 3A and 3D of the Intel^® Stratix^® 10 TX 400, GX 400, and SX 400 devices.

2.1.2. Intel Stratix 10 I/O Standards Voltage Support

Intel^® Stratix^® 10 devices in all packages can interface with systems of different supply voltages.

The I/O buffers are powered by V_CC, V_CCPT and V_CCIO.
Each I/O bank has its own V_CCIO supply and supports only one V_CCIO voltage.
In all LVDS I/O banks, you can use any of the listed V_CCIO voltages except 2.5 V, 3.0 V, and 3.3 V. However, LVDS I/O bank 3D of the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices supports only 1.8 V V_CCIO.
The 2.5 V and 3.0 V V_CCIO voltages are supported only on the 3 V I/O banks.
The 3.3 V V_CCIO voltages are supported only on I/O bank 3C of the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices. I/O bank 3C of these devices also supports 3.0 V.
For the maximum and minimum input voltages allowed, refer to the device datasheet.

Table 3. Intel^® Stratix^® 10 Devices I/O Standards Voltage LevelsThis table lists the typical power supplies for each supported I/O standards in Intel^® Stratix^® 10 devices.
I/O Standard	V_CCIO(V)		V_CCPT(V) (Pre-Driver Voltage)	V_REF(V) (Input Ref Voltage)	V_TT(V) (Board Termination Voltage)
I/O Standard	Input⁸	Output	V_CCPT(V) (Pre-Driver Voltage)	V_REF(V) (Input Ref Voltage)	V_TT(V) (Board Termination Voltage)
3.3 V LVTTL/3.3 V LVCMOS ⁹	3.3	3.3	1.8	—	—
3.0 V LVTTL/3.0 V LVCMOS	3.0	3.0	1.8	—	—
2.5 V LVCMOS	3.0/2.5	2.5	1.8	—	—
1.8 V LVCMOS	1.8	1.8	1.8	—	—
1.5 V LVCMOS	1.5	1.5	1.8	—	—
1.2 V LVCMOS	1.2	1.2	1.8	—	—
SSTL-18 Class I and Class II	V_CCPT	1.8	1.8	0.9	0.9
SSTL-15 Class I and Class II	V_CCPT	1.5	1.8	0.75	0.75
SSTL-15	V_CCPT	1.5	1.8	0.75	0.75
SSTL-135	V_CCPT	1.35	1.8	0.675	0.675
SSTL-125	V_CCPT	1.25	1.8	0.625	0.625
SSTL-12	V_CCPT	1.2	1.8	0.6	0.6
POD12	V_CCPT	1.2	1.8	0.84	1.2
1.8 V HSTL Class I and Class II	V_CCPT	1.8	1.8	0.9	0.9
1.5 V HSTL Class I and Class II	V_CCPT	1.5	1.8	0.75	0.75
1.2 V HSTL Class I and Class II	V_CCPT	1.2	1.8	0.6	0.6
HSUL-12	V_CCPT	1.2	1.8	0.6	—
Differential SSTL-18 Class I and Class II	V_CCPT	1.8	1.8	—	0.9
Differential SSTL-15 Class I and Class II	V_CCPT	1.5	1.8	—	0.75
Differential SSTL-15	V_CCPT	1.5	1.8	—	0.75
Differential SSTL-135	V_CCPT	1.35	1.8	—	0.675
Differential SSTL-125	V_CCPT	1.25	1.8	—	0.625
Differential SSTL-12	V_CCPT	1.2	1.8	—	0.6
Differential POD12	V_CCPT	1.2	1.8	—	1.2
Differential 1.8 V HSTL Class I and Class II	V_CCPT	1.8	1.8	—	0.9
Differential 1.5 V HSTL Class I and Class II	V_CCPT	1.5	1.8	—	0.75
Differential 1.2 V HSTL Class I and Class II	V_CCPT	1.2	1.8	—	0.6
Differential HSUL-12	V_CCPT	1.2	1.8	—	—
LVDS ¹⁰	V_CCPT	1.8	1.8	—	—
Mini-LVDS ¹⁰	V_CCPT	1.8	1.8	—	—
RSDS¹⁰	V_CCPT	1.8	1.8	—	—
LVPECL (Differential clock input only)	V_CCPT	—	1.8	—	—

⁸ Input for the SSTL, HSTL, Differential SSTL, Differential HSTL, POD, Differential POD, LVDS, RSDS, Mini-LVDS, LVPECL, HSUL, and Differential HSUL are powered by V_CCPT

⁹ Available only on I/O bank 3C of the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices.

¹⁰ Supported only on dedicated clock pin in I/O banks 3A and 3D of the Intel^® Stratix^® 10 TX 400, GX 400, and SX 400 devices.

2.2. I/O Element Structure in Intel Stratix 10 Devices

The I/O elements (IOEs) in Intel^® Stratix^® 10 devices contain a bidirectional I/O buffer and I/O registers to support a complete embedded bidirectional single data rate (SDR) or double data rate (DDR) transfer.

The IOEs are located in I/O columns within the core fabric of the Intel^® Stratix^® 10 device.

Intel^® Stratix^® 10 SX devices also have IOEs for the HPS.

The GPIO IOE register consists of the DDR register, the half rate register, and the transmitter delay chains for input, output, and output enable (OE) paths:

You can take data from the combinatorial path or the registered path.
Only the core clock clocks the data.
The half rate clock routed from the core clocks the half rate register.
The full rate clock from the core clocks the full rate register.

2.2.1. I/O Bank Architecture in Intel Stratix 10 Devices

In each LVDS I/O bank, there are four I/O lanes with 12 I/O pins in each lane. Other than the I/O lanes, each I/O bank also contains dedicated circuitries including the I/O PLL, DPA block, SERDES, hard memory controller, and I/O sequencer.

However, the DPA block and SERDES are not available in the following I/O banks in package HF35 of the following devices:

Intel^® Stratix^® 10 GX 400 and SX 400 devices—I/O banks 3A, 3C, and 3D
Intel^® Stratix^® 10 TX 400 devices—I/O banks 3A and 3D

In each 3 V or 3.3 V I/O bank, there are eight single-ended I/O buffers. The 3.3 V I/O bank in package HF35 of the Intel^® Stratix^® 10 GX 400 and SX 400 devices supports only unidirectional single-ended 3.3 V or 3.0 V I/O buffers. In the 3.3 V I/O bank, the pins form eight-pin groups. You can configure all eight pins in a group together as all input only or all output only. To identify the pin groups, refer to the Optional Function(s) column in device pin out files.

Figure 5. I/O Bank StructureThis figure shows an example of I/O banks in one Intel^® Stratix^® 10 device. The I/O banks availability and locations vary among Intel^® Stratix^® 10 devices.

2.2.2. I/O Buffer and Registers in Intel Stratix 10 Devices

I/O registers are composed of the input path for handling data from the pin to the core, the output path for handling data from the core to the pin, and the output enable (OE) path for handling the OE signal to the output buffer. These registers allow faster source-synchronous register-to-register transfers and resynchronization. Use the GPIO Intel^® FPGA IP to utilize these registers to implement DDR circuitry.

The input and output paths contain the following blocks:

Input registers—support half or full rate data transfer from peripheral to core, and support double or single data rate data capture from I/O buffer.
Output registers—support half or full rate data transfer from core to peripheral, and support double or single data rate data transfer to I/O buffer.
OE registers—support half or full rate data transfer from core to peripheral, and support single data rate data transfer to I/O buffer.

The input and output paths also support the following features:

Clock enable.
Asynchronous or synchronous reset.
Bypass mode for input and output paths.
Delays chains on input and output paths.

Figure 6. IOE Structure for Intel^® Stratix^® 10 DevicesThis figure shows the Intel^® Stratix^® 10 FPGA IOE structure.

Note: The GPIOs in the 3 V I/O banks do not have I/O registers.

2.3. Programmable IOE Features in Intel Stratix 10 Devices

Table 4. Intel^® Stratix^® 10 Programmable IOE Features Settings and Assignment Name
Feature	Setting	Condition	Intel^® Quartus^® Prime Assignment Name
Slew Rate Control	0 (Slow), 1 (Fast). Default is 1.	Disabled if you use the R_S OCT feature.	`SLEW_RATE`
I/O Delay	Refer to the device datasheet	—	`INPUT_DELAY_CHAIN` `OUTPUT_DELAY_CHAIN`
Open-Drain Output	On, Off. Default is Off	—	`AUTO_OPEN_DRAIN_PINS`
Bus-Hold	On, Off. Default is Off.	Disabled if you use the weak pull-up resistor feature.	`ENABLE_BUS_HOLD_CIRCUITRY`
Weak Pull-up Resistor	On, Off. Default is Off.	Disabled if you use the bus-hold feature.	`WEAK_PULL_UP_RESISTOR`
Pre-Emphasis	0 (disabled), 1 (enabled). Default is 1.	—	`PROGRAMMABLE_PREEMPHASIS`
Differential Output Voltage	0 (low), 1 (medium low), 2 (medium high), 3 (high). Default is 2.	—	`PROGRAMMABLE_VOD`

Table 5. Intel^® Stratix^® 10 Programmable IOE Features I/O Buffer Types and I/O Standards SupportThis table lists the I/O buffer types and I/O standards that support the programmable IOE features. For information about which I/O standards are available for each I/O buffer type, refer to the related information.
Feature	I/O Buffer Type Support			I/O Standards Support
Feature	LVDS I/O	3 V I/O	HPS I/O (SoC Devices Only)	I/O Standards Support
Slew Rate Control ¹¹	Yes	Yes	Yes	3.0 V /3.3 V LVTTL 1.2 V, 1.5 V, 1.8 V, 2.5 V, and 3.0 V/3.3 V LVCMOS SSTL-18, SSTL-15, SSTL-135, SSTL-125, and SSTL-12 1.2 V, 1.5 V, and 1.8 V HSTL HSUL-12 POD12 Differential SSTL-18, Differential SSTL-15, Differential SSTL-135, Differential SSTL-125, and Differential SSTL-12 Differential 1.2 V, 1.5 V, and 1.8 V HSTL Differential HSUL-12
I/O Delay	Yes	Yes	—
Open-Drain Output¹¹	Yes	Yes	Yes	3.0 V LVTTL 1.2 V, 1.5 V, 1.8 V, and 3.0 V LVCMOS
Bus-Hold¹¹	Yes	Yes	—
Weak Pull-up Resistor¹¹	Yes	Yes	Yes
Pre-Emphasis	Yes	—	—	LVDS RSDS Mini-LVDS LVPECL With OCT fast slew rate mode: POD12 and Differential POD12 SSTL-12 and Differential SSTL-12
Differential Output Voltage	Yes	—	—	LVDS RSDS Mini-LVDS LVPECL

¹¹ Not available for the 3.3 V I/O bank (bank 3C) of the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices.

2.3.1. Programmable Output Slew Rate Control

You can specify the slew rate on a pin-by-pin basis because each I/O pin contains a slew rate control. The slew rate control affects both the rising and falling edges.

You can select between two slew rate settings, 1 and 0:

Fast slew rate (1)—provides high-speed transitions for high-performance systems. This is the default setting. If you enable on-chip termination (OCT), this setting is always used.
Slow slew rate (0)—reduces system noise and crosstalk but adds a nominal delay to the rising and falling edges.

Note: Intel recommends that you perform IBIS or SPICE simulations to determine the best slew rate setting for your specific application.

2.3.2. Programmable IOE Delay

You can activate the programmable IOE delays to ensure zero hold time, minimize setup time, or increase clock-to-output time. This feature helps read and write timing margins because it minimizes the uncertainties between signals in the bus.

To ensure that the signals within a bus have the same delay going into or out of the device, each pin can have different delay values:

Delay from input pin to input register
Delay from output pin to output register

For more information about the programmable IOE delay specifications, refer to the device datasheet.

2.3.3. Programmable Open-Drain Output

The programmable open-drain output provides a high-impedance state on output when logic to the output buffer is high. If logic to the output buffer is low, output is low.

You can attach several open-drain outputs to a wire. This connection type is like a logical OR function and is commonly called an active-low wired-OR circuit. If at least one of the outputs is in logic 0 state (active), the circuit sinks the current and brings the line to low voltage.

You can use open-drain output if you are connecting multiple devices to a bus. For example, you can use the open-drain output for system-level control signals that can be asserted by any device or as an interrupt.

You can enable the open-drain output assignment using one of these methods:

Design the tristate buffer using OPNDRN primitive.
Turn on the Auto Open-Drain Pins option in the Intel^® Quartus^® Prime software.

You can design open-drain output without enabling the option assignment. However, your design will not use the I/O buffer's open-drain output feature. The open-drain output feature of the I/O buffer provides you the best propagation delay from OE to output.

Note: Do not pull the output voltage higher than the Vi (DC) level. Intel recommends that you perform HSPICE simulation to verify the output voltage in your selected topology. You must ensure the output voltage meets the V_IH and V_IL requirements of the receiving device.

2.3.4. Programmable Bus Hold

Each I/O pin provides an optional bus-hold feature that is active only after configuration. When the device enters user mode, the bus-hold circuit captures the value that is present on the pin by the end of the configuration.

The bus-hold circuitry uses a resistor with a nominal resistance (R_BH), approximately 7 kΩ, to weakly pull the signal level to the last-driven state of the pin. The bus-hold circuitry holds this pin state until the next input signal is present. Because of this, you do not require an external pull-up or pull-down resistor to hold a signal level when the bus is tri-stated.

For each I/O pin, you can individually specify that the bus-hold circuitry pulls non-driven pins away from the input threshold voltage—where noise can cause unintended high-frequency switching. To prevent over-driving signals, the bus-hold circuitry drives the voltage level of the I/O pin lower than the V_CCIO level.

If you enable the bus-hold feature, you cannot use the programmable pull-up option. To configure the I/O pin for differential signals, disable the bus-hold feature.

2.3.5. Programmable Pull-Up Resistor

Each I/O pin provides an optional programmable pull-up resistor during user mode. The pull-up resistor weakly holds the I/O to the V_CCIO level.

The Intel^® Stratix^® 10 device supports programmable weak pull-up resistors only on user I/O pins but not on dedicated configuration pins, dedicated clock pins, or JTAG pins.

If you enable the weak pull-up resistor, you cannot use the bus-hold feature.

2.3.6. Programmable Pre-Emphasis

The V_OD setting and the output impedance of the driver set the output current limit of a high-speed transmission signal. At a high frequency, the slew rate may not be fast enough to reach the full V_OD level before the next edge, producing pattern-dependent jitter. With pre-emphasis, the output current is boosted momentarily during switching to increase the output slew rate.

Pre-emphasis increases the amplitude of the high-frequency component of the output signal, and thus helps to compensate for the frequency-dependent attenuation along the transmission line. The overshoot introduced by the extra current happens only during a change of state switching to increase the output slew rate and does not ring, unlike the overshoot caused by signal reflection. The amount of pre-emphasis required depends on the attenuation of the high-frequency component along the transmission line.

Figure 7. Programmable Pre-EmphasisThis figure shows the LVDS output with pre-emphasis.

Table 6. Intel^® Quartus^® Prime Software Assignment Editor—Programmable Pre-EmphasisThis table lists the assignment name for programmable pre-emphasis and its possible values in the Intel^® Quartus^® Prime software Assignment Editor.
Field	Assignment
To	`tx_out`
Assignment name	Programmable Pre-emphasis
Allowed values	0 (disabled), 1 (enabled). Default is 1.

2.3.7. Programmable Differential Output Voltage

The programmable V_OD settings allow you to adjust the output eye opening to optimize the trace length and power consumption. A higher V_OD swing improves voltage margins at the receiver end, and a smaller V_OD swing reduces power consumption. You can statically adjust the V_OD of the differential signal by changing the V_OD settings in the Intel^® Quartus^® Prime software Assignment Editor.

Figure 8. Differential V_OD This figure shows the V_OD of the differential LVDS output.

Table 7. Intel^® Quartus^® Prime Software Assignment Editor—Programmable V_OD This table lists the assignment name for programmable V_OD and its possible values in the Intel^® Quartus^® Prime software Assignment Editor.
Field	Assignment
To	`tx_out`
Assignment name	Programmable Differential Output Voltage (V_OD)
Allowed values	0 (low), 1 (medium low), 2 (medium high), 3 (high). Default is 2.

2.3.8. Programmable Current Strength

You can use the programmable current strength to mitigate the effects of high signal attenuation that is caused by a long transmission line or a legacy backplane.

Note:

To use programmable current strength, you must specify the current strength assignment in the Intel^® Quartus^® Prime software. Without explicit assignments, the Intel^® Quartus^® Prime software uses these predefined default values:

All HSTL and SSTL Class I, and all non-voltage-referenced I/O standards—50 Ω R_S OCT without calibration
All HSTL and SSTL Class II I/O standards—25 Ω R_S OCT without calibration
POD12 I/O standard—34 Ω R_S OCT without calibration

Table 8. Programmable Current Strength Settings for Intel^® Stratix^® 10 DevicesThe output buffer for each Intel^® Stratix^® 10 device I/O pin has a programmable current strength control for the I/O standards listed in this table.
I/O Standard	I_OH / I_OL Current Strength Setting (mA)
	Supported in FPGA			Supported in HPS ¹² (SoC Devices Only)
	Available		Default	Available	Default
3.3 V LVTTL ¹³	12, 8, 4		12	—	—
3.3 V LVCMOS¹³	12, 8, 4		12	—	—
3.0 V LVTTL	3.3 V I/O bank¹³	12, 8, 4	12	—	—
3.0 V LVTTL	3 V I/O bank ¹⁴	24, 20, 16, 12, 8, 4	12	—	—
3.0 V LVCMOS	3.3 V I/O bank¹³	12, 8, 4	12	—	—
3.0 V LVCMOS	3 V I/O bank¹⁴	24, 20, 16, 12, 8, 4	12	—	—
2.5 V LVCMOS	16, 12, 8, 4		12	—	—
1.8 V LVCMOS	16, 12, 10, 8, 6, 4, 2		12	12, 10, 8	12
1.5 V LVCMOS	12, 10, 8, 6, 4, 2		12	—	—
1.2 V LVCMOS	8, 6, 4, 2		8	—	—
SSTL-18 Class I	8, 6, 4		8	—	—
SSTL-18 Class II	8		8	—	—
SSTL-15 Class I	8, 6, 4		8	—	—
SSTL-15 Class II	8		8	—	—
SSTL-135	8, 6, 4		8	—	—
SSTL-125	8, 6, 4		8	—	—
SSTL-12	8, 6, 4		8	—	—
POD12	8, 6, 4		8	—	—
1.8 V HSTL Class I	12, 10, 8, 6, 4		8	—	—
1.8 V HSTL Class II	14		14	—	—
1.5 V HSTL Class I	12, 10, 8, 6, 4		8	—	—
1.5 V HSTL Class II	14		14	—	—
1.2 V HSTL Class I	8, 6, 4		8	—	—
Differential SSTL-18 Class I	8, 6, 4		8	—	—
Differential SSTL-18 Class II	8		8	—	—
Differential SSTL-15 Class I	8, 6, 4		8	—	—
Differential SSTL-15 Class II	8		8	—	—
Differential SSTL-135	12, 10, 8, 6, 4		8	—	—
Differential SSTL-125	12, 10, 8, 6, 4		8	—	—
Differential SSTL-12 Class I	12, 10, 8, 6, 4		8	—	—
Differential POD12	8, 6, 4		8	—	—
Differential 1.8 V HSTL Class I	12, 10, 8, 6, 4		8	—	—
Differential 1.8 V HSTL Class II	14		14	—	—
Differential 1.5 V HSTL Class I	12, 10, 8, 6, 4		8	—	—
Differential 1.5 V HSTL Class II	14		14	—	—
Differential 1.2 V HSTL Class I	8, 6, 4		8	—	—

Note: Intel recommends that you perform IBIS or SPICE simulations to determine the best current strength setting for your specific application.

¹² The programmable current strength information for the HPS is preliminary.

¹³ Available only on I/O bank 3C of the HF35 package of the Intel^® Stratix^® 10 GX 400 and SX 400 devices. The current strength setting control is per eight-pin groups basis. To identify the pin groups, refer to the Optional Function(s) column in device pin out files. For example, the group name is IO33_LS[<group index>]_[<pin index>].

¹⁴ Programmable slew rate control is applicable only for current strength settings of 16 mA and above.

2.4. On-Chip I/O Termination in Intel Stratix 10 Devices

Serial (R_S) and parallel (R_T) OCT provides I/O impedance matching and termination capabilities. OCT maintains signal quality, saves board space, and reduces external component costs.

The Intel^® Stratix^® 10 devices support OCT in all FPGA I/O banks with the following exceptions:

The 3 V I/Os support only OCT without calibration.
The 3.3 V I/Os do not support OCT.

Figure 9. Single-ended Termination (R_S and R_T) This figure shows the single-ended termination schemes supported in Intel^® Stratix^® 10 devices. R_T1 and R_T2 are dynamic parallel terminations and are enabled only if the device is receiving. In bidirectional applications, R_T1 and R_T2 are automatically switched on when the device is receiving and switched off when the device is driving.

Table 9. OCT Schemes Supported in Intel^® Stratix^® 10 Devices
Direction	OCT Schemes	I/O Type Support
Direction	OCT Schemes	LVDS I/O	3 V I/O	3.3 V I/O
Output	R_S OCT with calibration	Yes	—	—
Output	R_S OCT without calibration	Yes	Yes	—
Input	R_T OCT with calibration	Yes	—	—
Input	R_D OCT (LVDS I/O standard only)	Yes	—	—
Bidirectional	Dynamic R_S and R_T OCT	Yes	—	—

2.4.1. RS OCT without Calibration in Intel Stratix 10 Devices

Intel^® Stratix^® 10 devices support R_S OCT for single-ended and voltage-referenced I/O standards. R_S OCT without calibration is supported on output only.

Table 10. Selectable I/O Standards for R_S OCT Without CalibrationThis table lists the output termination settings for uncalibrated OCT on different I/O standards.
I/O Standard	Uncalibrated OCT (Output)
I/O Standard	R_S (Ω)
3.0 V LVTTL/3.0 V LVCMOS	25, 50
2.5 V LVCMOS	25, 50
1.8 V LVCMOS	25, 50
1.5 V LVCMOS	25, 50
1.2 V LVCMOS	25, 50
SSTL-18 Class I	50
SSTL-18 Class II	25
SSTL-15 Class I	50
SSTL-15 Class II	25
SSTL-15	34, 40
SSTL-135	34, 40
SSTL-125	34, 40
SSTL-12	34, 40, 60, 120, 240
POD12	34, 40, 48, 60
1.8 V HSTL Class I	50
1.8 V HSTL Class II	25
1.5 V HSTL Class I	50
1.5 V HSTL Class II	25
1.2 V HSTL Class I	50
1.2 V HSTL Class II	25
HSUL-12	34, 40, 48, 60, 80
Differential SSTL-18 Class I	50
Differential SSTL-18 Class II	25
Differential SSTL-15 Class I	50
Differential SSTL-15 Class II	25
Differential SSTL-15	34, 40
Differential SSTL-15 Class I	50
Differential SSTL-15 Class II	25
Differential SSTL-135	34, 40
Differential SSTL-125	34, 40
Differential SSTL-12	34, 40, 60, 120, 240
Differential POD12	34, 40, 48, 60
Differential 1.8 V HSTL Class I	50
Differential 1.8 V HSTL Class II	25
Differential 1.5 V HSTL Class I	50
Differential 1.5 V HSTL Class II	25
Differential 1.2 V HSTL Class I	50
Differential 1.2 V HSTL Class II	25
Differential HSUL-12	34, 40, 48, 60, 80

Driver-impedance matching provides the I/O driver with controlled output impedance that closely matches the impedance of the transmission line. As a result, you can significantly reduce signal reflections on PCB traces.

If you use impedance matching, you cannot specify the current strength.

Figure 10. R_S OCT Without CalibrationThis figure shows the R_S as the intrinsic impedance of the output transistors.

2.4.2. RS OCT with Calibration in Intel Stratix 10 Devices

The Intel^® Stratix^® 10 devices support R_S OCT with calibration in all LVDS I/O banks.

Table 11. Selectable I/O Standards for R_S OCT With CalibrationThis table lists the output termination settings for calibrated OCT on different I/O standards.
I/O Standard	Calibrated OCT (Output)
I/O Standard	R_S (Ω)	`RZQ` (Ω)
1.8 V LVCMOS	25, 50	100
1.5 V LVCMOS	25, 50	100
1.2 V LVCMOS	25, 50	100
SSTL-18 Class I	50	100
SSTL-18 Class II	25	100
SSTL-15 Class I	50	100
SSTL-15 Class II	25	100
SSTL-15	34, 40	240
SSTL-135	34, 40	240
SSTL-125	34, 40	240
SSTL-12	34, 40, 60, 120, 240	240
POD12	34, 40, 48, 60	240
1.8 V HSTL Class I	50	100
1.8 V HSTL Class II	25	100
1.5 V HSTL Class I	50	100
1.5 V HSTL Class II	25	100
1.2 V HSTL Class I	50	100
1.2 V HSTL Class II	25	100
HSUL-12	34, 40, 48, 60, 80	240
Differential SSTL-18 Class I	50	100
Differential SSTL-18 Class II	25	100
Differential SSTL-15 Class I	50	100
Differential SSTL-15 Class II	25	100
Differential SSTL-15	34, 40	240
Differential SSTL-135	34, 40	240
Differential SSTL-15 Class I	50	100
Differential SSTL-15 Class II	25	100
Differential SSTL-125	34, 40	240
Differential SSTL-12	34, 40, 60, 120, 240	240
Differential POD12	34, 40, 48, 60	240
Differential 1.8 V HSTL Class I	50	100
Differential 1.8 V HSTL Class II	25	100
Differential 1.5 V HSTL Class I	50	100
Differential 1.5 V HSTL Class II	25	100
Differential 1.2 V HSTL Class I	50	100
Differential 1.2 V HSTL Class II	25	100
Differential HSUL-12	34, 40, 48, 60, 80	240

The R_S OCT calibration circuit compares the total impedance of the I/O buffer to the external reference resistor connected to the RZQ pin and dynamically enables or disables the transistors until they match.

Calibration occurs at the end of device configuration. When the calibration circuit finds the correct impedance, the circuit powers down and stops changing the characteristics of the drivers.

Figure 11. R_S OCT with CalibrationThis figure shows the R_S as the intrinsic impedance of the output transistors.

2.4.3. RT OCT with Calibration in Intel Stratix 10 Devices

The Intel^® Stratix^® 10 devices support R_T OCT with calibration in all LVDS I/O banks but not in the 3 V I/O banks. R_T OCT with calibration is available only for configuration of input and bidirectional pins. Output pin configurations do not support R_T OCT with calibration. If you use R_T OCT, the V_CCIO of the bank must match the I/O standard of the pin where you enable the R_T OCT.

Table 12. Selectable I/O Standards for R_TOCT With CalibrationThis table lists the input termination settings for calibrated OCT on different I/O standards.
I/O Standard	Calibrated OCT (Input)
I/O Standard	R_T (Ω)	RZQ (Ω)
SSTL-18 Class I	50	100
SSTL-18 Class II	50	100
SSTL-15 Class I	50	100
SSTL-15 Class II	50	100
SSTL-15	48, 60,120	240
SSTL-135	48, 60, 120	240
SSTL-125	48, 60, 120	240
SSTL-12	60, 120	240
POD12	34, 40, 48, 60, 80, 120, 240	240
1.8 V HSTL Class I	50	100
1.8 V HSTL Class II	50	100
1.5 V HSTL Class I	50	100
1.5 V HSTL Class II	50	100
1.2 V HSTL Class I	50	100
1.2 V HSTL Class II	50	100
Differential SSTL-18 Class I	50	100
Differential SSTL-18 Class II	50	100
Differential SSTL-15 Class I	50	100
Differential SSTL-15 Class II	50	100
Differential SSTL-15	48, 60,120	240
Differential SSTL-135	48, 60, 120	240
Differential SSTL-125	48, 60, 120	240
Differential SSTL-12	60, 120	240
Differential POD12	34, 40, 48, 60, 80, 120, 240	240
Differential 1.8 V HSTL Class I	50	100
Differential 1.8 V HSTL Class II	50	100
Differential 1.5 V HSTL Class I	50	100
Differential 1.5 V HSTL Class II	50	100
Differential 1.2 V HSTL Class I	50	100
Differential 1.2 V HSTL Class II	50	100

The R_T OCT calibration circuit compares the total impedance of the I/O buffer to the external resistor connected to the RZQ pin. The circuit dynamically enables or disables the transistors until the total impedance of the I/O buffer matches the external resistor.

Calibration occurs at the end of the device configuration. When the calibration circuit finds the correct impedance, the circuit powers down and stops changing the characteristics of the drivers.

Figure 12. R_T OCT with Calibration

2.4.4. Dynamic OCT

Dynamic OCT is useful for terminating a high-performance bidirectional path by optimizing the signal integrity depending on the direction of the data. Dynamic OCT also helps save power because device termination is internal. Internal termination switches on only during input operation and thus draws less static power.

Note: If you use the SSTL-15, SSTL-135, and SSTL-125 I/O standards with the DDR3 memory interface, Intel recommends that you use OCT with these I/O standards to save board space and cost. OCT reduces the number of external termination resistors used.

Table 13. Dynamic OCT Based on Bidirectional I/ODynamic R_T OCT or R_S OCT is enabled or disabled based on whether the bidirectional I/O acts as a receiver or driver.
Dynamic OCT	Bidirectional I/O	State
Dynamic R_T OCT	Acts as a receiver	Enabled
Dynamic R_T OCT	Acts as a driver	Disabled
Dynamic R_S OCT	Acts as a receiver	Disabled
Dynamic R_S OCT	Acts as a driver	Enabled

Figure 13. Dynamic R_T OCT in Intel^® Stratix^® 10 Devices

2.4.5. Differential Input RD OCT

All I/O pins and dedicated clock input pins in Intel^® Stratix^® 10 devices support on-chip differential termination, R_D OCT. The Intel^® Stratix^® 10 devices provide a 100 Ω, on-chip differential termination option on each differential receiver channel for LVDS standards.

You can enable on-chip termination in the Intel^® Quartus^® Prime software Assignment Editor.

Figure 14. On-Chip Differential I/O Termination

Table 14. Intel^® Quartus^® Prime Software Assignment Editor—On-Chip Differential TerminationThis table lists the assignment name for on-chip differential termination in the Intel^® Quartus^® Prime software Assignment Editor.
Field	Assignment
To	`rx_in`
Assignment name	Input Termination
Value	Differential

2.4.6. OCT Calibration Block in Intel Stratix 10 Devices

You can calibrate the OCT using the OCT calibration block available in each I/O bank.

You can use R_S and R_T OCT in the same I/O bank for different I/O standards if the I/O standards use the same V_CCIO supply voltage. You cannot configure the R_S OCT and the programmable current strength for the same I/O buffer.

The OCT calibration process uses the RZQ pin that is available in every calibration block in a given I/O bank for series- and parallel-calibrated termination:

Each OCT calibration block has an external 240 Ω reference resistor associated with it through the RZQ pin.
Connect the RZQ pin to GND through an external 100 Ω or 240 Ω resistor (depending on the R_S or R_T OCT value).
The RZQ pin shares the same V_CCIO supply voltage with the I/O bank where the pin is located.
The RZQ pin is a dual-purpose I/O pin and functions as a general purpose I/O pin if you do not use the calibration circuit.

Intel^® Stratix^® 10 devices support calibrated R_S and calibrated R_T OCT on all LVDS I/O pins except for dedicated configuration pins.

2.5. External I/O Termination for Intel Stratix 10 Devices

Table 15. External Termination Schemes for Various I/O Standards
I/O Standard	External Termination Scheme
3.3 V LVTTL/3.3 V LVCMOS	No external termination required
3.0 V LVTTL/3.0 V LVCMOS
2.5 V LVCMOS
1.8 V LVCMOS
1.5 V LVCMOS
1.2 V LVCMOS
SSTL-18 Class I and Class II	Single-Ended SSTL I/O Standard Termination
SSTL-15 Class I and Class II	Single-Ended SSTL I/O Standard Termination
SSTL-15 ¹⁵	No external termination required
SSTL-135 ¹⁵
SSTL-125 ¹⁵
SSTL-12
POD12	Single-Ended POD I/O Standard Termination
1.8 V HSTL Class I and Class II	Single-Ended HSTL I/O Standard Termination
1.5 V HSTL Class I and Class II
1.2 V HSTL Class I and Class II
HSUL-12	No external termination required
Differential SSTL-18 Class I and Class II	Differential SSTL I/O Standard Termination
Differential SSTL-15 Class I and Class II	Differential SSTL I/O Standard Termination
Differential SSTL-15 ¹⁵	No external termination required
Differential SSTL-135 ¹⁵
Differential SSTL-125 ¹⁵
Differential SSTL-12
Differential POD12	Differential POD I/O Standard Termination
Differential 1.8 V HSTL Class I and Class II	Differential HSTL I/O Standard Termination
Differential 1.5 V HSTL Class I and Class II
Differential 1.2 V HSTL Class I and Class II
Differential HSUL-12	No external termination required
LVDS	LVDS I/O Standard Termination
RSDS	RSDS/mini-LVDS I/O Standard Termination
Mini-LVDS	RSDS/mini-LVDS I/O Standard Termination
LVPECL	Differential LVPECL I/O Standard Termination

¹⁵ Intel recommends that you use OCT with these I/O standards to save board space and cost. OCT reduces the number of external termination resistors used.

2.5.1. Single-Ended I/O Termination

Voltage-referenced I/O standards require an input V_REF and a termination voltage (V_TT). The reference voltage of the receiving device tracks the termination voltage of the transmitting device.

The supported I/O standards such as SSTL-12, SSTL-125, SSTL-135, and SSTL-15 typically do not require external board termination.

Intel recommends that you use OCT with these I/O standards to save board space and cost. OCT reduces the number of external termination resistors used.

Note: You cannot use R_S and R_T OCT simultaneously. For more information, refer to the related information.

Figure 15. SSTL I/O Standard TerminationThis figure shows the details of SSTL I/O termination on Intel^® Stratix^® 10 devices.

Figure 16. HSTL I/O Standard TerminationThis figure shows the details of HSTL I/O termination on the Intel^® Stratix^® 10 devices.

Figure 17. POD I/O Standard TerminationThis figure shows the details of POD I/O termination on the Intel^® Stratix^® 10 devices.

2.5.2. Differential I/O Termination for Intel Stratix 10 Devices

The I/O pins are organized in pairs to support differential I/O standards. Each I/O pin pair can support differential input and output buffers.

The supported I/O standards such as Differential SSTL-12, Differential SSTL-15, Differential SSTL-125, and Differential SSTL-135 typically do not require external board termination.

Intel recommends that you use OCT with these I/O standards to save board space and cost. OCT reduces the number of external termination resistors used.

2.5.2.1. Differential HSTL, SSTL, HSUL, and POD Termination

Differential HSTL, SSTL, HSUL, and POD inputs use LVDS differential input buffers. However, R_D support is only available if the I/O standard is LVDS.

Differential HSTL, SSTL, HSUL, and POD outputs are not true differential outputs. These I/O standards use two single-ended outputs with the second output programmed as inverted.

Figure 18. Differential SSTL I/O Standard TerminationThis figure shows the details of Differential SSTL I/O termination on Intel^® Stratix^® 10 devices.

Figure 19. Differential HSTL I/O Standard TerminationThis figure shows the details of Differential HSTL I/O standard termination on Intel^® Stratix^® 10 devices.

Figure 20. Differential POD I/O Standard TerminationThis figure shows the details of Differential POD I/O termination on the Intel^® Stratix^® 10 devices.

2.5.2.2. LVDS, RSDS, and Mini-LVDS Termination

All I/O banks have dedicated circuitry to support the true LVDS, RSDS, and mini-LVDS I/O standards by using true LVDS output buffers without resistor networks.

Figure 21. LVDS I/O Standard TerminationThis figure shows the LVDS I/O standard termination. The on-chip differential resistor is available in all I/O banks.

2.5.2.3. LVPECL Termination

The Intel^® Stratix^® 10 devices support the LVPECL I/O standard on input clock pins only:

LVPECL input operation is supported using LVDS input buffers.
LVPECL output operation is not supported.

Use AC coupling if the LVPECL common-mode voltage of the output buffer does not match the LVPECL input common-mode voltage.

Note: Intel recommends that you use IBIS models to verify your LVPECL AC/DC-coupled termination.

Figure 22. LVPECL AC-Coupled External Termination

Support for DC-coupled LVPECL is available if the LVPECL output common mode voltage is within the Intel^® Stratix^® 10 LVPECL input buffer specification.

Figure 23. LVPECL DC-Coupled External Termination

For information about the V_ICM specification, refer to the device datasheet.

3. Intel Stratix 10 I/O Design Considerations

There are several considerations that require your attention to ensure the success of your designs. Unless noted otherwise, these design guidelines apply to all variants of this device family.

3.1. Guideline: VREF Sources and VREF Pins

For Intel^® Stratix^® 10 devices, consider the following VREF pins guidelines:

Intel^® Stratix^® 10 devices support internal and external V_REF sources.
- There is an external VREF pin for every I/O bank, providing one external V_REF source for all I/Os in the same bank.
- Each I/O lane in the bank also has its own internal V_REF generator. You can configure each I/O lane independently to use its internal V_REF or the I/O bank's external V_REF source. All I/O pins in the same I/O lane use the same V_REF source.
You can use the internal V_REF with calibration to support DDR4 using the POD12 I/O standard.
You can place any combination of input, output, or bidirectional pins near VREF pins. There is no VREF pin placement restriction.
The VREF pins are dedicated for voltage-referenced single-ended I/O standards. You cannot use the VREF pins as user I/Os.
Connect unused VREF pins to GND.

For more information about pin capacitance of the VREF pins, refer to the device datasheet.

3.2. Guideline: Observe Device Absolute Maximum Rating for 3.0 V Interfacing

To ensure device reliability and proper operation when you use the device for 3.0 V I/O interfacing, do not violate the absolute maximum ratings of the device. For more information about absolute maximum rating and maximum allowed overshoot during transitions, refer to the device datasheet.

Tip: Perform IBIS or SPICE simulations to make sure the overshoot and undershoot voltages are within the specifications.

Single-Ended Transmitter Application

If you use the Intel^® Stratix^® 10 device as a transmitter, use slow slew rate and series termination to limit the overshoot and undershoot at the I/O pins. Transmission line effects that cause large voltage deviations at the receiver are associated with an impedance mismatch between the driver and the transmission lines. By matching the impedance of the driver to the characteristic impedance of the transmission line, you can significantly reduce overshoot voltage. You can use a series termination resistor placed physically close to the driver to match the total driver impedance to the transmission line impedance.

Single-Ended Receiver Application

If you use the Intel^® Stratix^® 10 device as a receiver, use an external clamping diode to limit the overshoot and undershoot voltage at the I/O pins.

The 3.0 V I/O standard is supported using the bank supply voltage (V_CCIO) at 3.0 V and a V_CCPT voltage of 1.8 V. In this method, the clamping diode can sufficiently clamp overshoot voltage to within the DC and AC input voltage specifications. The clamped voltage is expressed as the sum of the V_CCIO and the diode forward voltage.

3.3. Guideline: Voltage-Referenced and Non-Voltage Referenced I/O Standards

Each I/O bank can simultaneously support multiple I/O standards. Follow these guidelines if you use both non-voltage-referenced and voltage-referenced I/O standards in an I/O bank.

Non-Voltage-Referenced I/O Standards

An I/O bank can simultaneously support any number of input signals with different I/O standard assignments if the I/O standards support the V_CCIO level of the I/O bank.

For output signals, a single I/O bank supports non-voltage-referenced output signals that drive at the same voltage as V_CCIO. Because an I/O bank can only have one V_CCIO value, it can only drive out the value for non-voltage-referenced signals.

Voltage-Referenced I/O Standards

To accommodate voltage-referenced I/O standards:

Each Intel^® Stratix^® 10 FPGA I/O bank contains a dedicated VREF pin.
Each bank can have only a single V_CCIO voltage level and a single voltage reference (V_REF) level.

The voltage-referenced input buffer is powered by V_CCPT. Therefore, an I/O bank featuring single-ended or differential standards can support different voltage-referenced standards under the following conditions:

The V_REF are the same levels.
On-chip parallel termination (R_T OCT) is disabled.

If you enable R_T OCT, the voltage for the input standard and the V_CCIO of the bank must match.

This feature allows you to place voltage-referenced input signals in an I/O bank with a V_CCIO of 1.8 V or below. For example, you can place HSTL-15 input pins in an I/O bank with 1.8 V V_CCIO. However, the voltage-referenced input with R_T OCT enabled requires the V_CCIO of the I/O bank to match the voltage of the input standard. R_T OCT cannot be supported for the HSTL-15 I/O standard when V_CCIO is 1.8 V.

Voltage-referenced bidirectional and output signals must be the same as the V_CCIO voltage of the I/O bank. For example, you can place only SSTL-18 output pins in an I/O bank with a 1.8 V V_CCIO.

Mixing Voltage-Referenced and Non-Voltage Referenced I/O Standards

An I/O bank can support voltage-referenced and non-voltage-referenced pins by applying each of the rule sets individually.

Examples:

An I/O bank can support SSTL-18 inputs and outputs, and 1.8 V inputs and outputs with a 1.8 V V_CCIO and a 0.9 V V_REF.
An I/O bank can support 1.5 V standards, 1.8 V inputs (but not outputs), and 1.5 V HSTL I/O standards with a 1.5 V V_CCIO and 0.75 V V_REF.

3.4. Guideline: Do Not Drive I/O Pins During Power Sequencing

The Intel^® Stratix^® 10 I/O buffers are powered by V_CC, V_CCPT, and V_CCIO.

Because the Intel^® Stratix^® 10 devices do not support hot socketing, do not drive the I/O pins externally during power up and power down. This includes all I/O pins including FPGA and HPS I/Os. Adhere to this guideline to:

Avoid excess I/O pin current:
- Excess I/O pin current affects the device's lifetime and reliability.
- Excess current on the 3 V I/O pins can damage the Intel^® Stratix^® 10 device.
Achieve minimum current draw and avoid I/O glitch during power up or power down.
Avoid permanent damage on the 3 V I/O buffers in 3 V operation.

3.5. Guideline: Intel Stratix 10 I/O Buffer During Power Up, Configuration, and Power Down

During device power up and device configuration, all GPIO pins are tri-stated with weak pull-up enabled.
During device power down, all I/O pins are in undetermined state and the pin signal is measured between GND and the VCCIO level.
At any point,the input signal sof an I/O pin must not exceed the maximum DC input voltage specified in the device datasheet.

Figure 24. Intel^® Stratix^® 10 I/O Buffers Behavior

3.6. Guideline: Maximum DC Current Restrictions

There are no restrictions on the maximum DC current of any 10 consecutive I/O pins for Intel^® Stratix^® 10 devices.

Intel^® Stratix^® 10 devices conform to the V_CCIO Electro-Migration (EM) rule and IR drop targets for all I/O standard drive strength settings—ensuring reliability over the lifetime of the devices.

3.7. Guideline: Use Only One Voltage for All 3 V I/O Banks

A single VCCIO3V power pin powers all the 3 V I/O banks. Therefore, you can use only a single voltage level at any one time across all 3 V I/O banks in the Intel^® Stratix^® 10 device.

3.8. Guideline: I/O Standards Limitation for Intel Stratix 10 TX 400

On the Intel^® Stratix^® 10 TX 400 device, do not use the following I/O standards in I/O banks 3A and 3D except in dedicated clock pins:

LVDS
Mini-LVDS
RSDS

3.9. Guideline: I/O Standards Limitation for Intel Stratix 10 GX 400 and SX 400

On the Intel^® Stratix^® 10 GX 400 or SX 400 device, do not use the following I/O standards in I/O banks 3A and 3D except in dedicated clock pins:
- LVDS
- Mini-LVDS
- RSDS
Bank 3D has only 30 GPIO pins and supports only 1.8 V I/O standards.
Bank 3C supports only unidirectional single-ended I/O in 3.3 V or 3.0 V I/O standard.
In bank 3C, the control of I/O direction and features such as current strength is per eight-pin groups basis.
- To identify the pin groups, refer to the Optional Function(s) column in device pin out files. For example, the group name is IO33_LS[<group index>]_[<pin index>].
- As an example, if you configure any I/O pins from group LS1 as input, all the other pins in the group use the same setting. Similarly, if you use a pin in group LS0 as an output pin with 12 mA current strength, all pins in group LS0 apply the same setting.
- You cannot configure input and output pins in the same group. You can only use all eight pins as input, or all eight pins as output.
If you use 3 V I/O standard in the design without assigning pin locations, the Intel^® Quartus^® Prime software automatically assigns the pins to bank 3C. If you want to assign the 3 V I/O standard to the 3 V I/O bank, specify the USE_AS_3V_GPIO Intel^® Quartus^® Prime assignment to the pin in the .qsf file.

Table 16. Example of Eight-Pin Groups in Bank 3C
Pin Group	Entry in Optional Function(s) Column	Pin Name
LS1	`IO33_LS1_0`	`Y2`
	`IO33_LS1_1`	`AA2`
	`IO33_LS1_2`	`AB1`
	`IO33_LS1_3`	`AB2`
	`IO33_LS1_4`	`AC1`
	`IO33_LS1_5`	`AD1`
	`IO33_LS1_6`	`AF2`
	`IO33_LS1_7`	`AG2`
LS0	`IO33_LS0_0`	`U3`
	`IO33_LS0_1`	`V3`
	`IO33_LS0_2`	`U5`
	`IO33_LS0_3`	`V4`
	`IO33_LS0_4`	`W2`
	`IO33_LS0_5`	`Y1`
	`IO33_LS0_6`	`W3`
	`IO33_LS0_7`	`W4`

4. Intel Stratix 10 I/O Implementation Guides

You can implement your I/O design in the Intel^® Quartus^® Prime software. The software contains tools for you to create and compile your design, and configure your device.

The Intel^® Quartus^® Prime software allows you to prepare for device migration, set pin assignments, define placement restrictions, setup timing constraints, and customize IP cores. For more information about using the Intel^® Quartus^® Prime software, refer to the related information.

4.1. GPIO Intel FPGA IP

The GPIO IP core supports the GPIO components and features of the Intel^® Stratix^® 10 device family. You can use the Intel^® Quartus^® Prime parameter editor to configure the GPIO IP core.

Components of the GPIO IP core:

Double data rate input/output (DDIO)—doubles or halves the data-rate of a communication channel
Delay chains—configure the delay chains to perform specific delay and assist in I/O timing closure
I/O buffers—connect the pads to the FPGA

4.1.1. Release Information for GPIO Intel FPGA IP

Intel^® FPGA IP versions match the Intel^® Quartus^® Prime Design Suite software versions until v19.1. Starting in Intel^® Quartus^® Prime Design Suite software version 19.2, Intel^® FPGA IP has a new versioning scheme.

The Intel^® FPGA IP version (X.Y.Z) number can change with each Intel^® Quartus^® Prime software version. A change in:

X indicates a major revision of the IP. If you update the Intel^® Quartus^® Prime software, you must regenerate the IP.
Y indicates the IP includes new features. Regenerate your IP to include these new features.
Z indicates the IP includes minor changes. Regenerate your IP to include these changes.

Table 17. GPIO Intel^® FPGA IP Core Current Release Information
Item	Description
IP Version	19.3.0
Intel^® Quartus^® Prime Version	20.3
Release Date	2020.09.28

4.1.2. GPIO Intel FPGA IP Data Paths

Figure 25. High-Level View of Single-Ended GPIO

Table 18. GPIO IP Core Data Path Modes
Data Path	Register Mode
	Bypass	Simple Register	DDR I/O
	Bypass	Simple Register	Full-Rate	Half-Rate
Input	Data goes from the delay element to the core, bypassing all double data rate I/Os (DDIOs).	The full-rate DDIO operates as a simple register, bypassing half-rate DDIOs. The Fitter chooses whether to pack the register in the I/O or implement the register in the core, depending on the area and timing trade-offs.	The full-rate DDIO operates as a regular DDIO, bypassing the half-rate DDIOs.	The full-rate DDIO operates as a regular DDIO. The half-rate DDIOs convert full-rate data to half-rate data.
Output	Data goes from the core straight to the delay element, bypassing all DDIOs.	The full-rate DDIO operates as a simple register, bypassing half-rate DDIOs. The Fitter chooses whether to pack the register in the I/O or implement the register in the core, depending on the area and timing trade-offs.	The full-rate DDIO operates as a regular DDIO, bypassing the half-rate DDIOs.	The full-rate DDIO operates as a regular DDIO. The half-rate DDIOs convert full-rate data to half-rate data.
Bidirectional	The output buffer drives both an output pin and an input buffer.	The full-rate DDIO operates as a simple register. The output buffer drives both an output pin and an input buffer.	The full-rate DDIO operates as a regular DDIO. The output buffer drives both an output pin and an input buffer. The input buffer drives a set of three flip-flops.	The full-rate DDIO operates as a regular DDIO. The half-rate DDIOs convert full-rate data to half-rate. The output buffer drives both an output pin and an input buffer. The input buffer drives a set of three flip-flops.

If you use asynchronous clear and preset signals, all DDIOs share these same signals.

Half-rate and full-rate DDIOs connect to separate clocks. When you use half-rate and full-rate DDIOs, the full-rate clock must run at twice the half-rate frequency. You can use different phase relationships to meet timing requirements.

4.1.2.1. Input Path

The pad sends data to the input buffer, and the input buffer feeds the delay element. After the data goes to the output of the delay element, the programmable bypass multiplexers select the features and paths to use.

Each LVDS I/O input path contains two stages of DDIOs, which are full-rate and half-rate.

The 3 V I/Os do not support DDIOs.

Figure 26. Simplified View of Single-Ended GPIO Input Path

The pad receives data.
DDIO IN (1) captures data on the rising and falling edges of ck_fr and sends the data, signals (A) and (B) in the following waveform figure, at single data rate.
DDIO IN (2) and DDIO IN (3) halve the data rate.
dout[3:0] presents the data as a half-rate bus.

Figure 27. Input Path Waveform in DDIO Mode with Half-Rate Conversion

In this figure, the data goes from full-rate clock at double data rate to half-rate clock at single data rate. The data rate is divided by four and the bus size is increased by the same ratio. The overall throughput through the GPIO IP core remains unchanged.

The actual timing relationship between different signals may vary depending on the specific design, delays, and phases that you choose for the full-rate and half-rate clocks.

Note: The GPIO Intel^® FPGA IP and OCT Intel^® FPGA IP support OCT during power up and user mode on single-directional input or output pins. The GPIO IP does not support dynamic OCT of bidirectional pins. For applications that require dynamic OCT control for bidirectional pins, refer to the related information.

4.1.2.2. Output and Output Enable Paths

The output delay element sends data to the pad through the output buffer.

Each LVDS I/O output path contains two stages of DDIOs, which are half-rate and full-rate.

The 3 V I/Os do not support DDIOs.

Figure 28. Simplified View of Single-Ended GPIO Output Path

Figure 29. Output Path Waveform in DDIO Mode with Half-Rate Conversion

Figure 30. Simplified View of Output Enable Path

The difference between the output path and output enable (OE) path is that the OE path does not contain full-rate DDIO. To support packed-register implementations in the OE path, a simple register operates as full-rate DDIO. For the same reason, only one half-rate DDIO is present.

The OE path operates in the following three fundamental modes:

Bypass—the core sends data directly to the delay element, bypassing all DDIOs.
Packed Register—bypasses half-rate DDIO.
SDR output at half-rate—half-rate DDIOs convert data from full-rate to half-rate.

In Intel^® Stratix^® 10 devices, each 3 V I/O bank supports only two output enables (OE) for its eight single-ended I/Os.

4.1.3. Register Packing

The GPIO IP core allows you to pack register into the periphery to save area and resource utilization.

You can configure the full-rate DDIO on the input and output path as a flip flop. To do so, add the .qsf assignments listed in this table.

Table 19. Register Packing QSF Assignments
Path	QSF Assignment
Input register packing	`set_instance_assignment -name FAST_INPUT_REGISTER ON -to <path to register>`
Output register packing	`set_instance_assignment -name FAST_OUTPUT_REGISTER ON -to <path to register>`
Output enable register packing	`set_instance_assignment -name FAST_OUTPUT_ENABLE_REGISTER ON -to <path to register>`

Note: These assignments do not guarantee register packing. However, these assignments enable the Fitter to find a legal placement. Otherwise, the Fitter keeps the flip flop in the core.

4.2. Verifying Resource Utilization and Design Performance

You can refer to the Intel^® Quartus^® Prime compilation reports to get details about the resource usage and performance of your design.

On the menu, click Processing > Start Compilation to run a full compilation.
After compiling the design, click Processing > Compilation Report.
Using the Table of Contents, navigate to Fitter > Resource Section.
1. To view the resource usage information, select Resource Usage Summary.
2. To view the resource utilization information, select Resource Utilization by Entity.

4.3. GPIO Intel FPGA IP Timing

The performance of the GPIO IP core depends on the I/O constraints and clock phases. To validate the timing for your GPIO configuration, Intel recommends that you use the Timing Analyzer.

4.3.1. Timing Components

The GPIO IP core timing components consist of three paths.

I/O interface paths—from the FPGA to external receiving devices and from external transmitting devices to the FPGA.
Core interface paths of data and clock—from the I/O to the core and from the core to I/O.
Transfer paths—from half-rate to full-rate DDIO, and from full-rate to half-rate DDIO.

Note: The Timing Analyzer treats the path inside the DDIO_IN and DDIO_OUT blocks as black boxes.

Figure 31. Input Path Timing Components

Figure 32. Output Path Timing Components

Figure 33. Output Enable Path Timing Components

4.3.2. Delay Elements

The Intel^® Quartus^® Prime software does not automatically set delay elements to maximize slack in the I/O timing analysis. To close the timing or maximize slack, set the delay elements manually in the Intel^® Quartus^® Prime settings file (.qsf).

Table 20. Delay Elements .qsf AssignmentsSpecify these assignments in the .qsf to access the delay elements.
Delay Element	.qsf Assignment
Input Delay Element	`set_instance_assignment –to <PIN> -name INPUT_DELAY_CHAIN <0..63>`
Output Delay Element	`set_instance_assignment –to <PIN> -name OUTPUT_DELAY_CHAIN <0..15>`
Output Enable Delay Element	`set_instance_assignment –to <PIN> -name OE_DELAY_CHAIN <0..15>`

4.3.3. Timing Analysis

The Intel^® Quartus^® Prime software does not automatically generate the SDC timing constraints for the GPIO IP core. You must manually enter the timing constraints.

Follow the timing guidelines and examples to ensure that the Timing Analyzer analyzes the I/O timing correctly.

To perform proper timing analysis for the I/O interface paths, specify the system level constraints of the data pins against the system clock pin in the .sdc file.
To perform proper timing analysis for the core interface paths, define these clock settings in the .sdc file:
- Clock to the core registers
- Clock to the I/O registers for the simple register and DDIO modes

4.3.3.1. Single Data Rate Input Register

Figure 34. Single Data Rate Input Register

Table 21. Single Data Rate Input Register .sdc Command Examples
Command	Command Example	Description
`create_clock`	`create_clock -name sdr_in_clk -period "100 MHz" sdr_in_clk`	Creates clock setting for the input clock.
`set_input_delay`	`set_input_delay -clock sdr_in_clk 0.15 sdr_in_data`	Instructs the Timing Analyzer to analyze the timing of the input I/O with a 0.15 ns input delay.

4.3.3.2. Full-Rate or Half-Rate DDIO Input Register

The input side of the full-rate and half-rate DDIO input registers are the same. You can properly constrain the system by using a virtual clock to model the off-chip transmitter to the FPGA.

Figure 35. Full-Rate or Half-Rate DDIO Input Register

Table 22. Full-Rate or Half-Rate DDIO Input Register .sdc Command Examples
Command	Command Example	Description
`create_clock`	`create_clock -name virtual_clock -period "200 MHz"` `create_clock -name ddio_in_clk -period "200 MHz" ddio_in_clk`	Create clock setting for the virtual clock and the DDIO clock.
`set_input_delay`	`set_input_delay -clock virtual_clock 0.25 ddio_in_data` `set_input_delay -add_delay -clock_fall -clock virtual_clock 0.25 ddio_in_data`	Instruct the Timing Analyzer to analyze the positive clock edge and the negative clock edge of the transfer. Note the `-add_delay` in the second `set_input_delay` command.
`set_false_path`	`set_false_path -fall_from virtual_clock -rise_to ddio_in_clk` `set_false_path -rise_from virtual_clock -fall_to ddio_in_clk`	Instruct the Timing Analyzer to ignore the positive clock edge to the negative edge triggered register, and the negative clock edge to the positive edge triggered register. Note: The `ck_hr` frequency must be half the `ck_fr` frequency. If the I/O PLL drives the clocks, you can consider using the `derive_pll_clocks` .sdc command.

4.3.3.3. Single Data Rate Output Register

Figure 36. Single Data Rate Output Register

Table 23. Single Data Rate Output Register .sdc Command Examples
Command	Command Example	Description
`create_clock` and `create_generated_clock`	`create_clock -name sdr_out_clk -period "100 MHz" sdr_out_clk` `create_generated_clock -source sdr_out_clk -name sdr_out_outclk sdr_out_outclk`	Generate the source clock and the output clock to transmit.
`set_output_delay`	`set_output_delay -clock sdr_out_clk 0.45 sdr_out_data`	Instructs the Timing Analyzer to analyze the output data to transmit against the output clock to transmit.

4.3.3.4. Full-Rate or Half-Rate DDIO Output Register

The output side of the full-rate and half-rate DDIO output registers are the same.

Table 24. DDIO Output Register .sdc Command Examples
Command	Command Example	Description
`create_clock` and `create_generated_clock`	`create_clock -name ddio_out_fr_clk -period "200 MHz" ddio_out_fr_clk` `create_generated_clock -source ddio_out_fr_clk -name ddio_out_fr_outclk ddio_out_fr_outclk`	Generate the clocks to the DDIO and the clock to transmit.
`set_output_delay`	`set_output_delay -clock ddio_out_fr_outclk 0.55 ddio_out_fr_data` `set_output_delay -add_delay -clock_fall -clock ddio_out_fr_outclk 0.55 ddio_out_fr_data`	Instruct the Timing Analyzer to analyze the positive and negative data against the output clock.
`set_false_path`	`set_false_path -rise_from ddio_out_fr_clk -fall_to ddio_out_fr_outclk` `set_false_path -fall_from ddio_out_fr_clk -rise_to ddio_out_fr_outclk`	Instruct the Timing Analyzer to ignore the rising edge of the source clock against the falling edge of the output clock, and the falling edge of source clock against rising edge of output clock

4.3.4. Timing Closure Guidelines

For the GPIO input registers, the input I/O transfer is likely to fail the hold time if you do not set the input delay chain. This failure is caused by the clock delay being larger than the data delay.

To meet the hold time, add delay to the input data path using the input delay chain. In general, the input delay chain is around 30 ps per step at the –1 speed grade. To get an approximate input delay chain setting to pass the timing, divide the negative hold slack by 60 ps.

However, if the I/O PLL drives the clocks of the GPIO input registers (simple register or DDIO mode), you can set the compensation mode to source synchronous mode. The Fitter will attempt to configure the I/O PLL for a better setup and hold slack for the input I/O timing analysis.

For the GPIO output and output enable registers, you can add delay to the output data and clock using the output and output enable delay chains.

If you observe setup time violation, you can increase the output clock delay chain setting.
If you observe hold time violation, you can increase the output data delay chain setting.

4.4. GPIO Intel FPGA IP Design Examples

The GPIO IP core can generate design examples that match your IP configuration in the parameter editor. You can use these design examples as references for instantiating the IP core and the expected behavior in simulations.

You can generate the design examples from the GPIO IP core parameter editor. After you setting the parameters that you want, click Generate Example Design. The IP core generates the design example source files in the directory you specify.

Figure 37. Source Files in the Generated Design Example Directory

Note: The .qsys files are for internal use during design example generation only. You cannot edit these .qsys files.

4.4.1. GPIO IP Core Synthesizable Intel Quartus Prime Design Example

The synthesizable design example is a compilation-ready Platform Designer system that you can include in an Intel^® Quartus^® Prime project.

Generating and Using the Design Example

To generate the synthesizable Intel^® Quartus^® Prime design example from the source files, run the following command in the design example directory:

quartus_sh -t make_qii_design.tcl

To specify an exact device to use, run the following command:

quartus_sh -t make_qii_design.tcl [device_name]

The TCL script creates a qii directory that contains the ed_synth.qpf project file. You can open and compile this project in the Intel^® Quartus^® Prime software.

4.4.2. GPIO IP Core Simulation Design Example

The simulation design example uses your GPIO IP core parameter settings to build the IP instance connected to a simulation driver. The driver generates random traffic and internally checks the legality of the out going data.

Using the design example, you can run a simulation using a single command, depending on the simulator that you use. The simulation demonstrates how you can use the GPIO IP core.

Generating and Using the Design Example

To generate the simulation design example from the source files for a Verilog simulator, run the following command in the design example directory:

quartus_sh -t make_sim_design.tcl

To generate the simulation design example from the source files for a VHDL simulator, run the following command in the design example directory:

quartus_sh -t make_sim_design.tcl VHDL

The TCL script creates a sim directory that contains subdirectories—one for each supported simulation tool. You can find the scripts for each simulation tool in the corresponding directories.

4.5. Verifying Pin Migration Compatibility

You can use the Pin Migration View window in the Intel^® Quartus^® Prime software Pin Planner to assist you in verifying whether your pin assignments migrate to a different device successfully. You can vertically migrate to a device with a different density while using the same device package, or migrate between packages with different densities and ball counts.

Open Assignments > Pin Planner and create pin assignments.
If necessary, perform one of the following options to populate the Pin Planner with the node names in the design:
- Analysis & Elaboration
- Analysis & Synthesis
- Fully compile the design
Then, on the menu, click View > Pin Migration View.
To select or change migration devices:
1. Click Device to open the Device dialog box.
2. Under Migration compatibility click Migration Devices.
To show more information about the pins:
1. Right-click anywhere in the Pin Migration View window and select Show Columns.
2. Then, click the pin feature you want to display.
If you want to view only the pins, in at least one migration device, that have a different feature than the corresponding pin in the migration result, turn on Show migration differences.
Click Pin Finder to open the Pin Finder dialog box to find and highlight pins with specific functionality.
If you want to view only the pins highlighted by the most recent query in the Pin Finder dialog box, turn on Show only highlighted pins.
To export the pin migration information to a Comma-Separated Value file (.csv), click Export.

4.6. IP Migration to the GPIO IP Core

The GPIO IP core can migrate your GPIO IPs from previous devices to work in Intel^® Stratix^® 10 designs.

Depending on the mode you use in your previous IP, the IP migration tool can automatically configure the new GPIO IP core based on settings in your previous IP. For unsupported modes, you can use the GPIO IP core parameter editor to manually configure the migrated IP core.

4.6.1. Migrating Your ALTDDIO_IN, ALTDDIO_OUT, ALTDDIO_BIDIR, and ALTIOBUF IP Cores

To migrate your ALTDDIO_IN, ALTDDIO_OUT, ALTDDIO_BIDIR, and ALTIOBUF IP cores to the GPIO Intel^® FPGA IP IP core, follow these steps:

Open your ALTDDIO_IN, ALTDDIO_OUT, ALTDDIO_BIDIR, or ALTIOBUF IP core in the IP Parameter Editor.
In the Currently selected device family, select Stratix 10.
Click Finish to open the GPIO IP Parameter Editor.
The IP Parameter Editor configures the GPIO IP core settings similar to the ALTDDIO_IN, ALTDDIO_OUT, ALTDDIO_BIDIR, or ALTIOBUF core settings.
If there are any incompatible settings between the two, select new supported settings.
Click Finish to regenerate the IP core.
Replace your ALTDDIO_IN, ALTDDIO_OUT, ALTDDIO_BIDIR, or ALTIOBUF IP core instantiation in RTL with the GPIO IP core.

Note: The GPIO IP core port names may not match the ALTDDIO_IN, ALTDDIO_OUT, ALTDDIO_BIDIR, or ALTIOBUF IP core port names. Therefore, simply changing the IP core name in the instantiation may not be sufficient.

4.6.2. Guideline: Swap datain_h and datain_l Ports in Migrated IP

When you migrate your GPIO IP from previous devices to the GPIO IP core, you can turn on Use legacy top-level port names option in the GPIO IP core parameter editor. However, the behavior of these ports in the GPIO IP core is different than in the IP cores used for the Stratix^® V, Arria^® V, and Cyclone^® V devices.

The GPIO IP core drives these ports to the output registers on these clock edges:

datain_h—on the falling edge of outclock
datain_l—on the rising edge of outclock

If you migrated your GPIO IP from Stratix^® V, Arria^® V, and Cyclone^® V devices, swap the datain_h and datain_l ports when you instantiate the IP generated by the GPIO IP core.

5. GPIO Intel FPGA IP Reference

You can set various parameter settings for the GPIO Intel^® FPGA IP to customize its behaviors, ports, and signals.

The Intel^® Quartus^® Prime software generates your customized GPIO IP core according to the parameter options that you set in the IP parameter editor.

5.1. GPIO Intel FPGA IP Parameter Settings

You can set the parameter settings for the GPIO IP core in the Intel^® Quartus^® Prime software. There are three groups of options: General, Buffer, and Registers.

Table 25. GPIO IP Core Parameters - General
Parameter	Condition	Allowed Values	Description
Data Direction	—	Input Output Bidir	Specifies the data direction for the GPIO.
Data width	—	1 to 128	Specifies the data width.
Use legacy top-level port names	—	On Off	Use same port names as in Stratix^® V, Arria^® V, and Cyclone^® V devices. For example, `dout` becomes `dataout_h` and `dataout_l`, and `din` becomes `datain_h` and `datain_l`. Note: The behavior of these ports are different than in the Stratix^® V, Arria^® V, and Cyclone^® V devices. For the migration guideline, refer to the related information.

Table 26. GPIO IP Core Parameters - Buffer
Parameter	Condition	Allowed Values	Description
Use differential buffer	—	On Off	If turned on, enables differential I/O buffers.
Use pseudo differential buffer	Data Direction = Output Use differential buffer = On	On Off	If turned on in output mode, enables pseudo differential output buffers. This option is automatically turned on for bidirectional mode if you turn on Use differential buffer.
Use bus-hold circuitry	Data Direction = Input or Bidir Use differential buffer = Off	On Off	If turned on, the bus hold circuitry can weakly hold the signal on an I/O pin at its last-driven state where the output buffer state will be 1 or 0 but not high-impedance.
Use open drain output	Data Direction = Output or Bidir Use differential buffer = Off	On Off	If turned on, the open drain output enables the device to provide system-level control signals such as interrupt and write enable signals that can be asserted by multiple devices in your system.
Enable output enable port	Data Direction = Output	On Off	If turned on, enables user input to the OE port. This option is automatically turned on for bidirectional mode. In Intel^® Stratix^® 10 devices, each 3 V I/O bank supports only two output enables (OE) for its eight single-ended I/Os.
Enable seriestermination / paralleltermination ports	—	On Off	If turned on, enables the `seriesterminationcontrol` and `parallelterminationcontrol` ports of the output buffer.

Table 27. GPIO IP Core Parameters - Registers
Parameter	Condition	Allowed Values	Description
Register mode	—	None Simple register DDIO	Specifies the register mode for the GPIO IP core: None—specifies a simple wire connection from/to the buffer. Simple register—specifies that the DDIO is used as a simple register in single data-rate mode (SDR). The Fitter may pack this register in the I/O. DDIO— specifies that the IP core uses the DDIO. If you use an I/O standard supported only by the 3 V I/O banks, select None.
Enable synchronous clear / preset port	Register mode = DDIO	None Clear Preset	Specifies how to implement synchronous reset port. None—Disables synchronous reset port. Clear—Enables the `SCLR` port for synchronous clears. Preset—Enables the `SSET` port for synchronous preset.
Enable asynchronous clear / preset port	Register mode = DDIO	None Clear Preset	Specifies how to implement asynchronous reset port. None—Disables asynchronous reset port. Clear—Enables the `ACLR` port for asynchronous clears. Preset—Enables the `ASET` port for asynchronous preset. `ACLR` and `ASET` signals are active high.
Enable clock enable ports	Register mode = DDIO	On Off	On—exposes the clock enable (`CKE`) port to allow you to control when data is clocked in or out. This signal prevents data from being passed through without your control. Off—clock enable port is not exposed and data always pass through the register automatically.
Half Rate logic	Register mode = DDIO	On Off	If turned on, enables half-rate DDIO.
Separate input / output Clocks	Data Direction = Bidir Register mode = Simple register or DDIO	On Off	If turned on, enables separate clocks (`CK_IN` and `CK_OUT`) for the input and output paths in bidirectional mode.

5.2. GPIO Intel FPGA IP Interface Signals

Depending on parameter settings you specify, different interface signals are available for the GPIO IP core.

Figure 38. GPIO IP Core Interfaces

Figure 39. GPIO Interface Signals

Table 28. Pad Interface SignalsThe pad interface is the physical connection from the GPIO IP core to the pad. This interface can be an input, output or bidirectional interface, depending on the IP core configuration. In this table, `SIZE` is the data width specified in the IP core parameter editor.
Signal Name	Direction	Description
`pad_in[SIZE-1:0]`	Input	Input signal from the pad.
`pad_in_b[SIZE-1:0]`	Input	Negative node of the differential input signal from the pad. This port is available if you turn on the Use differential buffer option.
`pad_out[SIZE-1:0]`	Output	Output signal to the pad.
`pad_out_b[SIZE-1:0]`	Output	Negative node of the differential output signal to the pad. This port is available if you turn on the Use differential buffer option.
`pad_io[SIZE-1:0]`	Bidirectional	Bidirectional signal connection with the pad.
`pad_io_b[SIZE-1:0]`	Bidirectional	Negative node of the differential bidirectional signal connection with the pad. This port is available if you turn on the Use differential buffer option.

Table 29. Data Interface SignalsThe data interface is an input or output interface from the GPIO IP core to the FPGA core. In this table, `SIZE` is the data width specified in the IP core parameter editor.
Signal Name	Direction	Description
`din[DATA_SIZE-1:0]`	Input	Data input from the FPGA core in output or bidirectional mode. `DATA_SIZE` depends on the register mode: Bypass or simple register— `DATA_SIZE` = `SIZE` DDIO without half-rate logic— `DATA_SIZE` = 2 × `SIZE` DDIO with half-rate logic— `DATA_SIZE` = 4 × `SIZE`
`dout[DATA_SIZE-1:0]`	Output	Data output to the FPGA core in input or bidirectional mode, `DATA_SIZE` depends on the register mode: Bypass or simple register— `DATA_SIZE` = `SIZE` DDIO without half-rate logic— `DATA_SIZE` = 2 × `SIZE` DDIO with half-rate logic— `DATA_SIZE` = 4 × `SIZE`
`oe[OE_SIZE-1:0]`	Input	OE input from the FPGA core in output mode with Enable output enable port turned on, or bidirectional mode. OE is active high. When transmitting data, set this signal to 1. When receiving data, set this signal to 0. `OE_SIZE` depends on the register mode: Bypass or simple register— `DATA_SIZE` = `SIZE` DDIO without half-rate logic— `DATA_SIZE` = `SIZE` DDIO with half-rate logic— `DATA_SIZE` = 2 × `SIZE`

Table 30. Clock Interface SignalsThe clock interface is an input clock interface. It consists of different signals, depending on the configuration. The GPIO IP core can have zero, one, two, or four clock inputs. Clock ports appear differently in different configurations to reflect the actual function performed by the clock signal.
Signal Name	Direction	Description
`ck`	Input	In input and output paths, this clock feeds a packed register or DDIO if you turn off the Half Rate logic parameter. In bidirectional mode, this clock is the unique clock for the input and output paths if you turn off the Separate input/output Clocks parameter.
`ck_fr`	Input	In input and output paths, these clocks feed the full-rate and half-rate DDIOs if your turn on the Half Rate logic parameter. In bidirectional mode, the input and output paths use these clocks if you turn off the Separate input/output Clocks parameter.
`ck_hr`	Input
`ck_in`	Input	In bidirectional mode, these clocks feed a packed register or DDIO in the input and output paths if you specify both these settings: Turn off the Half Rate logic parameter. Turn on the Separate input/output Clocks parameter.
`ck_out`	Input
`ck_fr_in`	Input	In bidirectional mode, these clocks feed a full-rate and half-rate DDIOS in the input and output paths if you specify both these settings Turn on the Half Rate logic parameter. Turn on the Separate input/output Clocks parameter. For example, `ck_fr_out` feeds the full-rate DDIO in the output path.
`ck_fr_out`
`ck_hr_in`
`ck_hr_out`
`cke`	Input	Clock enable.

Table 31. Termination Interface SignalsThe termination interface connects the GPIO IP core to the I/O buffers.
Signal Name	Direction	Description
`seriesterminationcontrol`	Input	Input from the termination control block (OCT) to the buffers. It sets the buffer series impedance value.
`parallelterminationcontrol`	Input	Input from the termination control block (OCT) to the buffers. It sets the buffer parallel impedance value.

Table 32. Reset Interface SignalsThe reset interface connects the GPIO IP core to the DDIOs.
Signal Name	Direction	Description
`sclr`	Input	Synchronous clear input. Not available if you enable `sset`.
`aclr`	Input	Asynchronous clear input. Active high. Not available if you enable `aset`.
`aset`	Input	Asynchronous set input. Active high. Not available if you enable `aclr`.
`sset`	Input	Synchronous set input. Not available if you enable `sclr`.

5.2.1. Shared Signals

The input, output, and OE paths share the same clear and preset signals.
The output and OE path shares the same clock signals.

5.2.2. Data Bit-Order for Data Interface

Figure 40. Data Bit-Order ConventionThis figure shows the bit-order convention for the din, dout and oe data signals.

If the data bus size value is SIZE, the LSB is at the right-most position.
If the data bus size value is 2 × SIZE, the bus is made of two words of SIZE .
If the data bus size value 4 × SIZE, the bus is made of four words of SIZE.
The LSB is in the right-most position of each word.
The right-most word specifies the first word going out for output buses and the first word coming in for input buses.

5.2.3. Data Interface Signals and Corresponding Clocks

Table 33. Data Interface Signals and Corresponding Clocks
Signal Name	Parameter Configuration			Clock
Signal Name	Register Mode	Half Rate	Separate Clocks
`din`	Simple Register DDIO	Off	Off	ck
	DDIO	On	Off	ck_hr
	Simple Register DDIO	Off	On	ck_in
	DDIO	On	On	ck_hr_in
`dout` `oe`	Simple Register DDIO	Off	Off	ck
	DDIO	On	Off	ck_hr
	Simple Register DDIO	Off	On	ck_out
	DDIO	On	On	ck_hr_out
`sclr` `sset` All pad signals	Simple Register DDIO	Off	Off	ck
	DDIO	On	Off	ck_fr
	Simple Register DDIO	Off	On	Input path: ck_in Output path: ck_out
	DDIO	On	On	Input path: ck_fr_in Output path: ck_fr_out

6. Intel Stratix 10 General Purpose I/O User Guide Archives

If the table does not list a software version, the user guide for the previous software version applies.

Intel^® Quartus^® Prime Version	User Guide
20.2	Intel^® Stratix^® 10 General Purpose I/O User Guide
19.4	Intel^® Stratix^® 10 General Purpose I/O User Guide
19.3	Intel^® Stratix^® 10 General Purpose I/O User Guide
19.2	Intel^® Stratix^® 10 General Purpose I/O User Guide
18.1	Intel^® Stratix^® 10 General Purpose I/O User Guide
18.0	Intel^® Stratix^® 10 General Purpose I/O User Guide
17.1	Intel^® Stratix^® 10 General Purpose I/O User Guide

7. Document Revision History for Intel Stratix 10 General Purpose I/O User Guide

Document Version	Intel^® Quartus^® Prime Version	Changes
2020.11.13	20.3	Updated the figure showing the I/O bank structure to add the pin naming orientation.
2020.08.25	20.2	Updated the topic about the I/O and differential I/O buffers to remove differential I/O support from 3 V I/O bank and to improve clarity.
2020.07.14	20.2	Added Intel^® Stratix^® 10 GX 10M to the figure showing the migration capability across Intel^® Stratix^® 10 GX and SX product lines. In the table listing the supported I/O standards voltage levels, updated the 3.3 V LVTTL/3.3 V LVCMOS row to support only 3.3 V VCCIO input, and the 3.0 V LVVTL/3.0 V LVCMOS row to support only 3.0 V VCCIO input. Updated the figure showing the I/O bank structure: Added I/O bank structure for Intel^® Stratix^® 10 GX 10M device. For I/O banks figure of other Intel^® Stratix^® 10 devices: Marked only bank 3A as SDM shared LVDS I/O Marked HPS shared LVDS I/Os Added 3 V I/O banks 7A, 7B, and 7C Updated the topic about programmable IOE delay to improve clarity. Removed the weak pull-up control feature in bank 3C of the HF35 package of Intel^® Stratix^® 10 GX 400 and SX 400 devices: Updated the programmable IOE features topic. Updated the I/O standards limitation guidelines for Intel^® Stratix^® 10 GX 400 and SX 400 devices. Updated the available programmable current strength settings for 3.3 V I/O standards. Added guideline topic about I/O buffer behavior during device power up, configuration, and power down.
2020.01.08	19.4	Updated the I/O migration topic to add and remove variants, product lines, packages, and migration paths. Added 3.3 V I/Os for package HF35 of the Intel^® Stratix^® 10 GX 400 and SX 400 devices. Added support for R_S OCT without calibration for 3 V I/Os. Updated the design guideline for I/O standards limitation in Intel^® Stratix^® 10 TX 400 devices to specify that you can use LVDS, mini-LVDS, or RSDS in banks 3A and 3D only as dedicated clock pins. Added design guideline for I/O standards limitation in Intel^® Stratix^® 10 GX 400 and SX 400 devices. Updated the programmable pre-emphasis diagram to remove the word "peak-peak". Added related information link from the topic about the programmable pull-up resistor feature to the Configuration Flow Diagram topic in the Intel^® Stratix^® 10 Configuration User Guide. The linked topic provides more information about weak-pull up in configuration mode. Updated the V_REF sources and `VREF` pins design guideline to remove `VCCIO` from the guideline about connecting unused `VREF` pins.
2019.10.01	19.3	Corrected typographical error in the .qsf assignment codes in the topic about delay elements.
2019.09.30	19.3	Added the Intel^® Stratix^® 10 TX 400 device to the vertical migration table. Added a guideline topic about using only one voltage for all 3 V I/O banks. Added a guideline topic about not using LVDS, Mini-LVDS, or RSDS I/O standards in banks 3A or 3D of the Intel^® Stratix^® 10 TX 400 device.
2019.07.09	19.2	Updated the notes in the topics about the input path, and output and output enable paths to specify that the GPIO Intel^® FPGA IP and OCT Intel^® FPGA IP support OCT on single-directional input or output pins only.
2019.03.04	18.1	In the topics about the input path, and output and output enable paths: Corrected the notes in the topics to specify that the GPIO Intel^® FPGA IP does not support dynamic calibration of bidirectional pins. Added links to the PHY Lite for Parallel Interfaces Intel^® FPGA IP Core User Guide: Intel^® Stratix^® 10, Intel^® Arria^® 10, and Intel^® Cyclone^® 10 GX Devices for more information about applications that require dynamic calibration for bidirectional pins.
2019.01.23	18.1	Updated the Intel^® Quartus^® Prime version of the document.
2019.01.14	18.1	Removed statement that says that the programmable V_OD value of "0" is not available for the LVDS I/O standard. In the topic about dynamic OCT, added link to PHY Lite for Parallel Interfaces Intel^® FPGA IP Core User Guide: Intel^® Stratix^® 10, Intel^® Arria^® 10, and Intel^® Cyclone^® 10 GX Devices for applications that require dynamic OCT for bidirectional pins.
2018.07.09	18.0	Added 24 mA and 20 mA current strength settings for the 3.0 V LVTTL I/O standard. Added Differential SSTL-15 Class I and Class II, and Differential SSTL-18 Class I and Class II to the table that lists the programmable current strengths. Added Differential SSTL-15 Class I and Class II to the tables that list the R_S OCT with calibration and R_S OCT without calibration. Removed 50 Ω R_T OCT for SSTL-15 and Differential SSTL-15 I/O standards. Added a note about not pulling the output voltage higher than the Vi (DC) level in the topic about the programmable open drain output.
2018.05.10	18.0	Updated a footnote related to 3 V I/O to specify that the 3 V I/O is not supported in the E-Tile transceiver tiles. Added a footnote to the I/O standards support table to specify that a transceiver tile's 3 V I/O bank is not available when the tile is powered down. Removed DDR2 support. Removed the topic about MultiVolt I/O interface and added the information to the topic about I/O standards voltage support. Moved the I/O count tables and I/O banks location figures to the pin-out files. Updated the figure titles in the topic about LVPECL termination to clarify that the figures refer to external termination. There is no OCT support for LVPECL I/O standard. Clarified that to utilize the I/O registers when implementing DDR circuitry, use the GPIO Intel^® FPGA IP in I/O Buffer and Registers in Intel^® Arria^® 10 Devices. Clarified that all singled-ended I/O configured to 3 V I/O bank supports all programmable I/O elements except programmable pre-emphasis, R_D on-chip termination (OCT), calibrated R_S and R_T OCT, and internal V_REF generation. Clarified that 3 V I/O bank supports single-ended and differential SSTL, HSTL, and HSUL I/O standards. Specified that `VREF` pins are dedicated for voltage-reference signal-ended I/O standards in Guideline: VREF Sources and VREF Pins. Clarified the type of I/O buffers available in Intel^® Arria^® 10 FPGA devices and Intel^® Arria^® 10 SoC devices in I/O Standards and Voltage Levels in Intel Stratix 10 Devices. Changed logic-to-pin to logic to the output buffer in Programmable Open-Drain Output section. Renamed the IP core from "Intel FPGA GPIO" to "GPIO Intel FPGA IP". Corrected instances of "clk_fr" and "clk_hr" to "ck_fr" and "ck_hr". Updated the GPIO IP core input path and output paths diagrams to show the actual IP core signal names. Updated the table listing the reset interface signals to improve clarity.

Date	Version	Changes
November 2017	2017.11.06	Clarified that each 3 V I/O bank supports only two OEs for its eight single-ended I/Os. Removed Intel^® Stratix^® 10 TX 4500 and TX 5500 devices. Added package SF48 to Intel^® Stratix^® 10 TX 1650 and TX 2100 devices. Added Intel^® Stratix^® 10 MX devices. Specified that 3 V I/Os are not available for Intel^® Stratix^® 10 devices with E-Tile transceiver variants. Updated descriptions of the table that lists the GPIO buffers and LVDS channels in Intel^® Stratix^® 10 GX devices to specify that the LVDS channels counts include dedicated clock pins. Removed the HF50 package from all Intel^® Stratix^® 10 devices. Restructured the topics and tables that list the I/O banks locations and pin counts. Added support for 2.5 V LVCMOS I/O standard. Added 3 V I/O bank support for the 1.8 V LVCMOS, 1.5 V LVCMOS, and 1.2 V LVCMOS I/O standards. Removed all instances of "DDR3U". Intel validates and support only IPs for memory interfaces listed in Performance Support Summary, Intel^® Stratix^® 10 External Memory Interfaces User Guide. Added a note to specify that to use the 1.2 V, 1.5 V, 1.8 V, and 2.5 V I/O standards on the 3 V I/O bank, you need to set the `USE_AS_3V_GPIO` assignment. Updated the tables that lists the programmable IOE features supported by the I/O buffer types and I/O standards. Removed the table that lists the I/O standards and current strengths that support programmable slew rate control. Added information about the default slew rate setting. Updated the topic about programmable IOE delay to remove the input and output delay information. The I/O delay numbers are pending characterization. Added information about the default predefined current strength if you do not specifically assign a current strength in the Intel^® Quartus^® Prime software. Updated the table listing the programmable current strength settings. Added current strength settings for these I/O standards: 2.5 V LVCMOS SSTL-135 and Differential SSTL-135 SSTL-125 and Differential SSTL-125 SSTL-12 and Differential SSTL-12 Class I POD12 and Differential POD12 Differential 1.8 V HSTL Class I and Class II Differential 1.5 V HSTL Class I and Class II Differential 1.2 V HSTL Class I Removed 6 mA, 4 mA, and 2 mA HPS current strength settings for the 1.8 V LVCMOS I/O standard Removed all HPS current strength settings except for the 1.8 V LVCMOS I/O standard Removed 12 mA and 10 mA current strength settings from the following I/O standards: 1.2 V LVCMOS SSTL-18 Class I SSTL-15 Class I 1.2 V HSTL Class I Removed 16 mA current strength settings from the SSTL-18 Class II and SSTL-15 Class II I/O standards Updated the current strength setting from 16 mA to 14 mA for the 1.8 V HSTL Class II and 1.5 V HSTL Class II I/O standards Removed programmable current strength for the 1.2 V HSTL Class II I/O standard Removed OCT support for 3 V I/O. Updated the tables listing the R_S and R_T OCT support to update I/O standards and available OCT settings. Updated the tables listing the external termination schemes to add 2.5 V LVCMOS. Updated the signal names in figures to match the signal names in the Intel FPGA GPIO IP core. Added the output path waveform. Renamed "Altera GPIO IP core" to "Intel FPGA GPIO IP core". Clarified that the `ASET` and `ACLR` signals are active high.
September 2017	2017.09.04	Added 8 mA to SSTL-2 Class II, SSTL-18 Class II, and SSTL-15 Class II, and removed 12 mA from SSTL-18 Class II in the list of current strength settings that support programmable output slew rate control. Added 8 mA current strength settings to SSTL-18 Class II and SSTL-15 Class II. Added these I/O standards to the table listing the selectable I/O standards for R_S OCT without calibration: Differential SSTL-15 Differential SSTL-135 Differential SSTL-125 Differential SSTL-12 Differential HSUL-12 Added 16 mA current strength setting to 1.8 V LVCMOS I/O standard. Added 12 mA and 10 mA current strength settings to 1.2 V LVCMOS I/O standard. Removed 25 Ω and 50 Ω R_S OCT settings from Differential SSTL-15 in the table that lists the selectable I/O standards for R_S OCT with calibration. Updated the table listing the Altera GPIO buffer parameters to specify the conditions for the Use bus-hold circuitry parameter option.
February 2017	2017.02.13	Removed the SF48 package from the Intel^® Stratix^® 10 TX 1650 and TX 2100 devices. Updated topics to clarify that the 3 V I/O banks do not have I/O registers and DDIOs, and do not support all features of the Altera GPIO IP core.
December 2016	2016.12.05	Corrected the number of I/Os in I/O bank 3L for the HF55 package of the GX 4500 and SX 5500 devices.
October 2016	2016.10.31	Initial release.