It is important to follow Intel design guidelines and recommendations throughout the
design process for Cyclone 10 LP designs.
design guidelines also assist you with planning the FPGA and system early in the design process,
which is crucial to successfully meet design requirements.
Note: For more information about
Cyclone 10 LP devices and features, refer to the
Cyclone 10 LP Core Fabric and General Purpose I/Os
The material references the Cyclone 10 LP
device architecture as well as aspects of the
software and third-party tools that you might use in your design. These guidelines can improve
productivity and avoid common design pitfalls.
Early power estimation, thermal management option, planning for
configuration scheme, planning for on-chip debugging
Pin Connection Considerations for Board Design
Power-up, power pins, PLL connections, decoupling capacitors,
configuration pins, signal integrity, board-level
I/O and Clock Planning
Pin assignments, early pin planning, I/O features and
connections, memory interfaces, clock and PLL selection,
simultaneous switching noise (SSN)
Coding styles and design recommendations, Qsys,
planning for hierarchical or team-based design
Design Implementation, Analysis, Optimization, and
Synthesis tool, device utilization, messages, timing constraints
and analysis, area and timing optimization, compilation time,
verification, power analysis and optimization
Figure 1. Cyclone 10 LP Device Design Flow
In systems that contain a Cyclone 10 LP device, the FPGA
typically plays a large role in the overall system and affects the rest of the system design.
It is important to start the design process by creating detailed design specifications for the
system and the FPGA, and determining the FPGA input and output interfaces to the rest of the
Table 2. Design Specifications Checklist
Create detailed design specifications and a test plan if appropriate.
Plan clock domains, clock resources, and I/O interfaces early with a block
Create detailed design specifications that define the system before you create your logic
design or complete your system design, by performing the following:
Specify the I/O interfaces for the FPGA
Identify the different clock domains
Include a block diagram of basic design functions
Include intellectual property (IP) blocks
Note: Taking the time to create
these specifications improves design efficiency, but this stage is often skipped by FPGA
Create a functional verification/test plan
Consider a common design directory structure
Create a functional verification plan to ensure the team knows how to verify the system.
Creating a test plan at this stage can also help you design for testability and design for
manufacturability. For example, do you want to perform built-in-self test (BIST) functions to
drive interfaces? If so, you could use a UART interface with a
processor inside the FPGA device. You might require the ability to validate all the design
If your design includes multiple designers, it is useful to consider a common design
directory structure. This eases the design integration stages.
Select IP that affects system design, especially I/O interfaces.
If you plan to use the OpenCore Plus tethered mode for IP, ensure that your board
design supports this mode of operation.
Intel and its third-party IP partners offer a large selection of
off-the-shelf IP cores optimized for Intel devices. You can easily
implement these parameterized blocks of IP in your design, reducing your system implementation
and verification time, and allowing you to concentrate on adding proprietary value.
IP selection often affects system design, especially if the FPGA interfaces with other
devices in the system. Consider which I/O interfaces or other blocks in your system design can
be implemented using IP cores, and plan to incorporate these cores in your FPGA design.
The OpenCore Plus feature available for many IP cores allows you to program the FPGA to
verify your design in hardware before you purchase the IP license. The evaluation supports an
untethered mode, in which the design runs for a limited time, or a tethered mode. The tethered
mode requires an Intel serial JTAG cable connected between the JTAG
port on your board and a host computer running the
Quartus® Prime Programmer for
the duration of the hardware evaluation period.
Take advantage of Qsys for system and
Qsys is a system integration tool included
as part of the
Quartus® Prime software. Qsys captures system-level hardware designs at a high level of abstraction and
automates the task of defining and integrating customized Hardware Description Language (HDL)
components. These components include IP cores, verification IP, and other design modules.
Qsys facilitates design reuse by packaging and
integrating your custom components with Intel and
third-party IP components. Qsys automatically creates
interconnect logic from the high-level connectivity you specify, thereby eliminating the
error-prone and time-consuming task of writing HDL to specify system-level connections.
Qsys is more powerful if you design your custom components using standard
interfaces. By using standard interfaces, your components inter-operate with the components in
the Qsys Library. In addition, you can take advantage of bus functional
models (BFMs), monitors, and other verification IP to verify your design.
Select a device based on transceivers, I/O pin count, LVDS
channels, package offering, logic/memory/multiplier density, PLLs, clock routing, and
The Cyclone 10 LP devices offer low power
with the lowest cost. If your application requires high-speed transceivers, refer to the Cyclone 10 GX Device Design Guidelines.
PLLs and Clock Routing
Table 6. PLLs and Clock Routing Checklist
Verify the number of PLLs and clock routing resources.
Verify that your chosen device density package combination includes enough PLLs and clock
routing resources for your design.
Logic, Memory, and Multiplier Density
Table 7. Logic, Memory, and Multiplier Density Checklist
Estimate the required logic, memory, and multiplier
Reserve device resources for future development and
Cyclone 10 LP devices offer a range of
densities that provide different amounts of device logic resources, including LEs, memory, and
multipliers. Determining the required logic density can be a challenging part of the design
planning process. Devices with more logic resources can implement larger and potentially more
complex designs, but generally have a higher cost. Smaller devices have lower static power
utilization. Cyclone 10 LP devices support vertical
migration, which provides flexibility.
Many next-generation designs use a current design as a starting point. If you have other
designs that target an Intel device, you can use
their resource utilization as an estimate for your new design. Review the resource utilization
to find out which device density fits the design. Consider that the coding style, device
architecture, and optimization options used in the
Quartus® Prime software can
significantly affect a design’s resource utilization and timing performance.
Select a device that meets your design requirements with some safety margin in case you want
to add more logic later in the design cycle, upgrade, or expand your design. You might also
want additional space in the device to ease design floorplan creation for an incremental or
team-based design. Consider reserving resources for debugging.
Consider the I/O pins you need to reserve for debugging.
Verify that the number of LVDS channels are enough.
Determine the required number of I/O pins for your application, considering
the design’s interface requirements with other system blocks.
Larger densities and package pin counts offer more full-duplex LVDS channels for different
signaling; ensure that your device density-package combination includes enough LVDS channels.
Other factors can also affect the number of I/O pins required for a design, including
simultaneous switching noise (SSN) concerns, pin placement guidelines, pins used as dedicated
inputs, I/O standard availability for each I/O bank, differences between I/O standards and
speed for row and column I/O banks, and package migration options.
You can compile any existing designs in the
software to determine how many I/O pins are used. Also consider reserving I/O pins for
Table 9. Speed Grade Checklist
Determine the device speed grade that you require.
The device speed grade affects the device timing performance and timing
closure, as well as power utilization. One way to determine which speed grade your design
requires is to consider the supported clock rates for specific I/O interfaces.
You can use the fastest speed grade during prototyping to reduce compilation
time (because less time is spent optimizing the design to meet timing requirements), and then
move to a slower speed grade for production to reduce cost if the design meets its timing
Vertical Device Migration
Table 10. Vertical Device Migration Checklist
Consider vertical device migration availability and
Cyclone 10 LP devices support vertical migration within the
same package, which enables you to migrate to different density devices whose dedicated input
pins, configuration pins, and power pins are the same for a given package. This feature allows
future upgrades or changes to your design without any changes to the board layout, because you
can replace the FPGA on the board with a different density Cyclone 10 LP device.
Determine whether you want the option of migrating your design to another device density.
Choose your device density and package to accommodate any possible future device migration to
allow flexibility when the design nears completion. You should specify any potential migration
options in the
Quartus® Prime software at the beginning of your
design cycle or as soon as the device migration selection is possible in the
Quartus® Prime software. Selecting a migration device can impact the
design’s pin placement, because the Fitter ensures your design is compatible with the selected
device(s). It is possible to add migration devices later in the design cycle, but it requires
extra effort to check pin assignments, and can require design or board layout changes to fit
into the new target device. It is easier to consider these issues early in the design cycle
than at the end, when the design is near completion and ready for migration.
Quartus® Prime Pin Planner highlights pins that change
function in the migration device when compared to the currently selected device.
System information related to the FPGA should be planned early in the design process, before
designers have completed the design in the
software. Early planning allows the FPGA team to provide early information to PCB board and
Early Power Estimation
Table 11. Early Power Estimation Checklist
Estimate power consumption with the Early Power Estimator (EPE)
spreadsheet to plan the cooling solution and power supplies before the logic design is
FPGA power consumption is an important design consideration and must be estimated accurately
to develop an appropriate power budget to design the power supplies, voltage regulators,
decouplers, heat sink, and cooling system. Power estimation and analysis have two significant
Thermal planning—The cooling solution must sufficiently dissipate the heat generated by
the device. In particular, the computed junction temperature must fall within normal device
Power supply planning—The power supplies must provide adequate current to support device
Power consumption in FPGA devices is dependent on the logic design. This
dependence can make power estimation challenging during the early board specification and
layout stages. The Intel EPE tool allows you to
estimate power utilization before the design is complete by processing information about the
device and the device resources that will be used in the design, as well as the operating
frequency, toggle rates, and environmental considerations. You can use the tool to perform
thermal analysis, including calculation of device junction temperatures derived from the
ambient temperature and device power consumption. The EPE then calculates the power, current
estimates, and thermal analysis for the design.
If you do not have an existing design, estimate the number of device
resources used in your design and enter it manually. The EPE tool accuracy depends on your
inputs and your estimation of the device resources. If this information changes (during or
after your design is complete), your power estimation results are less accurate. If you have
an existing design or a partially-completed compiled design, use the Generate Early Power Estimator File command in the
Quartus® Prime software to provide input to the spreadsheet.
The EPE spreadsheet includes the Import Data macro, which parses the
information in the
Quartus® Prime-generated power estimation file
(.csv), or alternatively from an older version of the EPE, and
transfers it into the EPE tool. If you do not want to use the macro, you can transfer the data
into the EPE tool manually. You should enter additional resources to be used in the final
design manually if the existing
Quartus® Prime project represents
only a portion of your full design. You can edit the inputs to the EPE tool and add additional
device resources or adjust the parameters after importing the power estimation file
When the design is complete, the Power Analyzer tool in the
Quartus® Prime software provides more accurate estimation of power,
ensuring that thermal and supply budgets are not violated. For the most accurate power
estimation, use gate-level simulation results with an output file (.vcd) from a third-party simulation tool.
Table 12. Planning for Device Configuration Checklist
Consider whether you require multiple configuration
Cyclone 10 LP devices are based on SRAM
cells. You must download configuration data to the Cyclone 10 LP device each time the device powers up, because SRAM is volatile.
Consider whether you require multiple configuration schemes, such as one for debugging or
testing and another for the production environment.
Choosing the device configuration method early allows system and board designers to determine
what companion devices, if any, are required for the system. Your board layout also depends on
the configuration method you plan to use for the programmable device, because different
schemes require different connections.
In addition, Cyclone 10 LP devices offer advanced
configuration features, depending on your configuration scheme. Cyclone 10 LP devices also include optional configuration pins and a
reconfiguration option that you should choose early in the design process (and set up in the
Quartus® Prime software), so you have all the information
required for your board and system design.
Select a configuration scheme to plan companion devices and board
Cyclone 10 LP devices offer several configuration
You can enable any specific configuration scheme by driving the Cyclone 10 LP device MSEL pins to specific values on the board.
All configuration schemes use a configuration device, a download cable, or an external
controller (for example,
MAX® 10) devices or microprocessor).
Serial Configuration Devices
Table 14. Serial Configuration Devices Checklist
If you want to use the AS configuration mode with large device
densities, confirm there is a configuration device available that is large enough for
your target FPGA density.
Serial configuration devices can be programmed using an Intel FPGA Download Cable or Intel FPGA Ethernet Cable with the
Quartus® Prime software through the active serial interface.
Alternatively, you can use supported third-party programmers such as BP
Microsystems and System General, or a microprocessor with the SRunner software driver. SRunner
is a software driver developed for embedded serial configuration device programming that
designers can customize to fit in different embedded systems.
Serial configuration devices do not directly support the JTAG interface; however, you can
program the device with JTAG download cables using the Cyclone 10 LP FPGA as a bridge between the JTAG interface and the configuration
device, allowing both devices to use the same JTAG interface.
Table 15. Download Cables Checklist
Use download cables for device configuration.
Quartus® Prime programmer supports configuration of the
Cyclone 10 LP devices directly using JTAG interfaces with
Intel programming download cables. You can download
design changes directly to the device with Intel
download cables, making prototyping easy and enabling you to make multiple design iterations
in quick succession. You can use the same download cable to program configuration devices on
the board and use JTAG debugging tools such as the Signal Tap Embedded Logic Analyzer.
Table 16. Configuration Features Checklist
Ensure your configuration scheme and board support the required
features: design security, remote upgrades, single event upset (SEU)
Cyclone 10 LP devices have a built-in dedicated circuitry
for error detection and correction. When enabled, this feature checks for SEUs continuously
and automatically. This allows you to confirm that the configuration data stored in a Cyclone 10 LP device is correct and alerts the system to a
To take advantage of the SEU mitigation features, turn on Enable error detection
CRC in the Device and Pin Options dialog box of the
software. Use the CRC_ERROR pin to flag errors and design your system to take
the appropriate action. If not enabled for the CRC function, the CRC_ERROR
pin is available as a user I/O pin.
Note: The SEU mitigation feature is available in all
Cyclone 10 LP devices with 1.2-V core
Quartus Prime Configuration Settings
Quartus® Prime Configuration Settings
configuration options when you plan your board and system design.
There are several configuration options that you can set in the
Quartus® Prime software before compilation to generate configuration or
programming files. Your board and system design are affected by these settings and pins, so
consider them in the planning stages. Set the options on the General category of the Device and Pin Options dialog box.
Optional Configuration Pins
Table 18. Optional Configuration Pins Checklist
Plan the board design to support optional configuration pins as
You can enable the following optional configuration pins:
Planning for On-Chip Debugging
On-chip debugging is an optional step in the design flow, and different
debugging tools work better for different systems and different designers. Evaluate on-chip
debugging options early in your design process to ensure that your system board,
Quartus® Prime project, and design are able to support the appropriate
options. Planning can reduce time spent debugging, and eliminates design changes later to
accommodate your preferred debugging methodologies. Adding debug pins might not be enough,
because of internal signal accessibility and I/O pin accessibility on the device. First,
select your preferred debugging tool(s).
On-Chip Debugging Tools
Table 19. On-Chip Debugging Tools Checklist
Take advantage of on-chip debugging features to analyze internal
signals and perform advanced debugging techniques.
Quartus® Prime portfolio of verification tools includes the
following in-system debugging features:
Signal Probe incremental routing—Quickly routes internal signals to I/O
pins without affecting the routing of the original design. Starting with a fully routed
design, you can select and route signals for debugging to either previously reserved or
currently unused I/O pins.
Signal Tap Embedded Logic
Analyzer—Probes the state of internal and I/O signals without the use of external equipment
or extra I/O pins, while the design is running at full speed in an FPGA device. Defining
custom trigger-condition logic provides greater accuracy and improves the ability to isolate
problems. It does not require external probes or changes to the design files to capture the
state of the internal nodes or I/O pins in the design; all captured signal data is stored in
the device memory until you are ready to read and analyze the data. The Signal Tap Embedded Logic Analyzer works best for synchronous
interfaces. For debugging asynchronous interfaces, consider using Signal Probe or an
external logic analyzer to view the signals more accurately.
Logic Analyzer Interface—Enables you to connect and transmit internal FPGA signals to an
external logic analyzer for analysis, allowing you to take advantage of advanced features in
your external logic analyzer or mixed signal oscilloscope. You can use this feature to
connect a large set of internal device signals to a small number of output pins for
debugging purposes and it can multiplex signals with design I/O pins if required.
In-System Memory Content Editor—Provides read and write access to in-system FPGA memories
and constants through the JTAG interface, so you can test changes to memory content and
constant values in the FPGA while the device is functioning in the system.
In-System Sources and Probes—Sets up customized register chains to drive or sample the
instrumented nodes in your logic design, providing an easy way to input simple virtual
stimuli and capture the current value of instrumented nodes.
Virtual JTAG IP core—Enables you to build your own system-level debugging infrastructure,
including both processor-based debugging solutions and debugging tools in the software for
system-level debugging. You can instantiate the SLD_VIRTUAL_JTAG IP core directly in your
HDL code to provide one or more transparent communication channels to access parts of your
FPGA design using the JTAG interface of the device.
Planning Guidelines for Debugging Tools
Table 20. Planning Guidelines for Debugging Tools Checklist
Select on-chip debugging scheme(s) early to plan memory and logic
requirements, I/O pin connections, and board connections.
If you want to use Signal Probe incremental routing, the Signal Tap Embedded Logic Analyzer, Logic Analyzer
Interface, In-System Memory Content Editor, In-System Sources and Probes, or Virtual
JTAG IP core, plan your system and board with JTAG connections that are available for
Plan for the small amount of additional logic resources used to
implement the JTAG hub logic for JTAG debugging features.
For debugging with the Signal Tap Embedded Logic Analyzer, reserve device memory resources to
capture data during system operation.
Reserve I/O pins for debugging with Signal Probe or the Logic
Analyzer Interface so you do not have to change the design or board to accommodate
debugging signals later.
Ensure the board supports a debugging mode where debugging
signals do not affect system operation.
Incorporate a pin header or mictor connector as required for an
external logic analyzer or mixed signal oscilloscope.
To use debug tools incrementally and reduce compilation time,
ensure incremental compilation is on so you do not have to recompile the design to
modify the debug tool.
To use the Virtual JTAG IP core for custom debugging
applications, instantiate it in the HDL code as part of the design process.
To use the In-System Sources and Probes feature, instantiate the
IP core in the HDL code.
To use the In-System Memory Content Editor for RAM or ROM blocks
or the LPM_CONSTANT IP core, turn on the Allow In-System Memory Content
Editor to capture and update content independently of the system clock
option for the memory block in the IP catalog.
If you intend to use any of the on-chip debugging tools, plan for the tool(s) when developing
the system board,
Quartus® Prime project, and design.
Pin Connection Considerations for Board Design
When designing the interfaces to the Cyclone 10 LP device,
various factors can affect the PCB design.
Table 21. Device Power-Up Checklist
Design board for power-up: All Cyclone 10 LP GPIO pins are tri-stated until the device is configured and
the configuration pins drive out.
Design voltage power supply ramps to be monotonic.
Set POR time to ensure power supplies are stable.
Design power sequencing and voltage regulators for best device
reliability. Connect the GND between boards before connecting the power
Cyclone 10 LP device I/O pins are hot-socketing compliant
without external components. You can insert or remove a Cyclone 10 LP device from a powered-up system board without damaging or interfering
with normal system and board operation.
You can drive signals into the I/O pins before or during power up or power down without
damaging the device. Cyclone 10 LP devices support power up
or power down of the VCCINT, VCCA, and
VCCIO pins in any sequence to simplify the system level design. The
individual power supply ramp-up and ramp-down rates can range from 50 µs to 50 ms. The power
ramp must be monotonic.
In a hot-socketing situation, the Cyclone 10 LP device’s
output buffers are turned off during system power up or power down. Also, the Cyclone 10 LP device does not drive out until the device is
configured and working within the recommended operating conditions.
Hot-socketing circuitry is not available on CONF_DONE,
nCEO, and nSTATUS configuration pins because they are
required during configuration. Therefore, it is expected behavior for these pins to drive out
during power-up and power-down sequences.
The POR circuit keeps the entire system in reset until the power supply voltage levels have
stabilized after power up. After power up, the device does not release
nSTATUS until VCCINT, VCCA, and VCCIO for
the I/O banks that contain configuration pins are above the POR trip point of the device.
After power down, brown-out occurs if the VCCINT or VCCA voltage
sags below the POR trip point. In Cyclone 10 LP devices, you
can select a fast or standard POR time, depending on the MSEL pin settings.
The fast POR time is 3 ms < TPOR < 9 ms for a fast configuration time. The
standard POR time is 50 ms < TPOR < 200 ms, which has a lower power-ramp
When power is applied to a Cyclone 10 LP device, a POR
event occurs if the power supply reaches the recommended operating range within a certain
period of time (specified as a maximum power supply ramp time; tRAMP). The maximum
power supply ramp time for Cyclone 10 LP devices is 50 ms
for standard POR or 3 ms for fast POR, while the minimum power supply ramp time is 50 µs.
Although power sequencing is not a requirement for correct operation, you should consider the
power-up timing for each rail to prevent problems with long-term device reliability when
designing a multi-rail powered system. You can reduce the device in-rush current with proper
sequencing and voltage regulator design.
Note:Intel recommends that you connect the GNDs
between boards before connecting the power supplies to ensure device reliability and
compliance to the hot-socketing specification.
Power Pin Connections and Power Supplies
Table 22. Power Pin Connections and Power Supplies Checklist
Connect all power pins correctly as specified in the
Cyclone 10 LP Device Family Pin
Connect VCCIO pins and VREF
pins to support each bank’s I/O standards.
Explore unique requirements for FPGA power pins or other power
pins on your board, and determine which devices on your board can share a power
Follow the suggested power supply sharing and isolation guidance,
and the specific guidelines for each pin in the
Cyclone 10 LP Device Family Pin Connection
Cyclone 10 LP devices support a wide range
of industry I/O standards. The device output pins do not meet the I/O standard specifications
if the VCCIO level is out of the recommended operating range for
the I/O standard.
Voltage reference (VREF) pins serve as voltage references for certain I/O
standards. The VREF pin is used mainly for a voltage bias and does not source
or sink much current. The voltage can be created with a regulator or a resistor divider
Table 23. Decoupling Capacitors Checklist
Use the PDN tool to plan your power distribution netlist and
Board decoupling is important for improving overall power supply integrity while ensuring the
rated device performance.
Cyclone 10 LP devices include on-die
decoupling capacitors to provide high-frequency decoupling. These low-inductance capacitors
suppress power noise for excellent power integrity performance, and reduce the number of
external PCB decoupling capacitors, saving board space, reducing cost, and greatly simplifying
For each power supply, PDN designers must choose a network of bulk and decoupling capacitors.
While SPICE simulation could be used to simulate the circuit, the PDN design tool provides a
fast, accurate, and interactive way to determine the right number of decoupling capacitors for
optimal cost and performance trade-offs.
PLL Board Design Guidelines
Table 24. PLL Board Design Guidelines Checklist
Connect all PLL power pins to reduce noise even if the design
does not use all the PLLs.
Power supply nets should be provided by an isolated power plane,
a power plane cut out, or thick trace of at least 20 mils.
Plan your board design when you design a power system for PLL usage and to minimize jitter,
because PLLs contain analog components embedded in a digital device.
Configuration Pin Connections
Table 25. Configuration Pin Connections Checklist
Check that all configuration pin connections and
pull-up/pull-down resistors are set correctly for your configuration
Depending on your configuration scheme, different pull-up/pull-down resistor
or signal integrity requirements might apply. Some configuration pins also have specific
requirements if unused. It is very important to connect the configuration pins correctly. The
following guidelines address the common issues.
Clock Trace Signal Integrity
Table 26. Clock Trace Signal Integrity Checklist
Design configuration clock traces to be noise-free.
Board trace for clocks used in configuration, for example TCK and DCLK clock input, should
produce clean signals with no overshoot, undershoot, or ringing. When designing the board, lay
out the configuration clock traces with the same techniques used to lay out a clock line. Any
overshoot, undershoot, ringing, or other noise on the clock signal can cause configuration
Table 27. JTAG Pins Checklist
Connect JTAG pins to a stable voltage level if not in
Because JTAG configuration takes precedence over all other configuration
methods, the JTAG pins should not be left floating or toggling during configuration if you do
not use the JTAG interface. If you are using the JTAG interface, adhere to the following
JTAG Pin Connections
Table 28. JTAG Pin Connections Checklist
Connect JTAG pins correctly to the download cable header. Ensure
the pin order is not reversed.
To disable the JTAG state machine during power-up, pull the
TCK pin low through a resistor to ensure that an
unexpected rising edge does not occur on the TCK
Pull the TMS and TDI pins high through a resistor.
A device operating in JTAG mode uses four required pins—TDI, TDO, TMS, and
TCK. The TCK pin has an
internal weak pull-down resistor, while the TDI and TMS pins have weak internal pull-up resistors.
If you have more than one device in the chain, connect the TDO pin of a
device to the TDI pin of the next device in the chain.
Noise on the JTAG pins during configuration, user mode, or power-up can cause the device to
go into an undefined state or mode.
Download Cable Operating Voltage
Table 29. Download Cable Operating Voltage Checklist
Ensure the download cable and JTAG pin voltages are compatible
because the download cable interfaces with the JTAG pins of your device.
The operating voltage supplied to the Intel download
cable by the target board through the 10-pin header determines the operating voltage level of
the download cable.
JTAG pins in the Cyclone 10 LP device are
powered up by VCCIO. In a JTAG chain containing devices with
different voltage levels, devices with a higher voltage must drive devices with the same or
lower voltage level. Level shifter might be required between devices to meet the voltage
specifications of the devices input pin.
JTAG Signal Buffering
Table 30. JTAG Signal Buffering Checklist
Buffer JTAG signals per the recommendations, especially for
connectors or if the cable drives more than three devices.
If your device is in a configuration chain, ensure all devices in
the chain are connected properly.
You might have to add buffers to a JTAG chain, depending on the JTAG signal integrity,
especially the TCK signal, because it is the JTAG clock and the fastest
switching JTAG signal. Intel recommends buffering the
signals at the connector because cables and board connectors tend to make bad transmission
lines and introduce noise to the signals. After this initial buffer at the connector, add
buffers as the chain gets longer or whenever the signals cross a board connector.
If a cable drives three or more devices, buffer the JTAG signal at the cable
connector to prevent signal deterioration. This also depends on the board layout, loads,
connectors, jumpers, and switches on the board. Anything added to the board that affects the
inductance or capacitance of the JTAG signals increases the likelihood that a buffer should be
added to the chain.
Each buffer should drive no more than eight loads for the TCK and
TMS signals, which drive in parallel. If jumpers or switches are added to
the path, decrease the number of loads.
MSEL Configuration Mode Pins
Table 31. MSEL Configuration Mode Pins Checklist
Connect the MSEL pins to select the
configuration scheme; do not leave them floating.
Select the configuration scheme by driving the MSEL pins high
or low. JTAG configuration is always available, regardless of the MSEL settings. The
MSEL pins are powered by the VCCINT power
To avoid problems detecting an incorrect configuration scheme, hardwire the
MSEL pins to VCCA or GND without pull-up or pull-down
resistors. You must not drive the MSEL pins with a microprocessor or another
Other Configuration Pins
Table 32. Other Configuration Pins Checklist
Hold nCE (chip enable) low during configuration,
initialization, and user mode.
In a single-device configuration or JTAG programming, tie
nCE low. In a multi-device configuration, tie nCE low on the first device
and connect its nCEO pin to the nCE pin on the next device
in the chain.
Board-Related Quartus Prime Settings
Table 33. Board-Related
Quartus® Prime Settings
Set the options for the FPGA I/O pins correctly and plan for the
functionality during board design.
Quartus® Prime software provides options for the FPGA I/O
pins that you should consider during board design. Ensure that these options are set correctly
Quartus® Prime project is created, and plan for the
functionality during board design.
Device-Wide Output Enable Pin
Table 34. Device-Wide Output Enable Pin Checklist
Turn on the device-wide output enable option, if
Cyclone 10 LP devices support an optional
chip-wide output enable that allows you to override all tri-states on the device I/Os. When
this DEV_OE pin is driven low, all I/O pins are tri-stated;
when this pin is driven high, all pins behave as programmed. To use this chip-wide output
enable, turn on Enable device-wide output enable
(DEV_OE) in the
Quartus® Prime software before
compiling your design in the General category of the Device and Pin Options dialog box. Ensure this pin is driven to a
valid logic level on your board if you enable this pin in the
Quartus® Prime software. Do not leave this pin floating.
Table 35. Unused Pins Checklist
Specify the reserved state for unused I/O pins.
Carefully check the pin connections in the
Quartus® Prime software-generated .pin
file. Do not connect RESERVED pins.
You can specify the state of unused pins in the
Quartus® Prime software to allow flexibility in the board design by choosing one of the
five allowable states for Reserve all unused pins on
the Unused Pins category in the Device and
Pin Options dialog box:
As inputs tri-stated
As output driving ground
As outputs driving an unspecified signal
As input tri-stated with bus-hold circuitry
As input tri-stated with weak pull-up
The common setting is to set unused pins As inputs tri-stated with weak
pull-up. To improve signal integrity, set the unused pins to As
output driving ground. Doing this reduces inductance by creating a shorter
return path and reduces noise on the neighboring I/Os. This approach should not be used if
this results in many via paths causing congestion for signals under the device.
To reduce power dissipation, set clock pins and other unused I/O pins As inputs
tri-stated, and tie them to ground.
Signal Integrity Considerations
Signal integrity considerations include detailed board design guidelines, as
well as a few guidelines related to VREF pins, SSN, and I/O
Voltage Reference Pins
Table 36. Voltage Reference Pins Checklist
Design VREF pins to be noise-free.
Voltage deviation on a VREF pin can affect the threshold sensitivity for
Simultaneous Switching Noise
Table 37. Simultaneous Switching Noise Checklist
Break out large bus signals on board layers close to the device
to reduce cross talk.
Route traces orthogonally if two signal layers are next to each
other, if possible. Use a separation of two to three times the trace width.
SSN is a concern when too many pins (in close proximity) change voltage levels at the same
time. Noise generated by SSN can reduce the noise margin and cause incorrect switching.
Although SSN is dominant on the device package, plan the board layout according to the board
layout recommendations in the PCB guidelines can help with noise reduction.
Table 38. I/O Termination Checklist
Check I/O termination and impedance matching for chosen I/O
standards, especially for voltage-referenced standards.
Voltage-referenced I/O standards require both an VREF and a termination voltage (VTT). The reference voltage
of the receiving device tracks the termination voltage of the transmitting device. Each
voltage-referenced I/O standard requires a unique termination setup.
Although single-ended, non-voltage-referenced I/O standards do not require
termination, impedance matching is necessary to reduce reflections and improve signal
Cyclone 10 LP on-chip series termination
provides the convenience of no external components. Alternatively, you can use external
pull-up resistors to terminate the voltage-referenced I/O standards such as SSTL and HSTL.
Differential I/O standards typically require a termination resistor between
the two signals at the receiver. The termination resistor must match the differential load
impedance of the signal line.
Board-Level Simulation and Advanced I/O Timing Analysis
Table 39. Board-Level Simulation and Advanced I/O Timing Analysis
Perform board-level simulation using IBIS models (when
Configure board trace models for
Quartus® Prime advanced I/O timing analysis.
To ensure that the I/O signaling meets receiver threshold levels on your board setup, perform
full board routing simulation with third-party board-level simulation tools using an IBIS
When this feature is available in the
Quartus® Prime software,
select IBIS under Board-level signal integrity
analysis on the Board-Level page in EDA Tool
Settings of the Settings dialog box.
When you include an FPGA device with high-speed interfaces in a board design, knowing the
signal integrity and board routing propagation delay is vital for proper system operation. You
should analyze board level timing as part of the I/O and board planning, especially for
You can configure board trace models of selected I/O standards and generate “board-aware”
signal integrity reports with the
Quartus® Prime software. When
Enable Advanced I/O Timing is turned on (TimeQuest Timing
Analyzer page in the Settings dialog box), the TimeQuest
Timing Analyzer uses simulation results for the I/O buffer, package, and the board trace model
to generate more accurate I/O delays and extra reports to give insight into signal behavior at
the system level. You can use these advanced timing reports as a guide to make changes to the
I/O assignments and board design to improve timing and signal integrity.
I/O and Clock Planning
Planning and allocating I/O and clock resources is an important task with the high pin counts
and advanced clock management features in Cyclone 10 LP
devices. Various considerations are important to effectively plan the available I/O resources
to maximize utilization and prevent issues related to signal integrity. Good clock management
systems are also crucial to the performance of an FPGA design.
The I/O and clock connections of your FPGA affect the rest of your system and board design,
so it is important to plan these connections early in your design cycle.
Quartus® Prime Pin Planner
to make pin assignments.
Quartus® Prime Fitter messages
and reports for sign-off of pin assignments.
Verify that the
Quartus® Prime pin
assignments match those in the schematic and board layout tools.
Plan interfaces and device periphery using the BluePrint Platform Designer. After
design synthesis, use BluePrint to rapidly define a legal device floorplan. BluePrint
planning involves initialization of BluePrint, reconciliation of project assignments,
placement of periphery elements and clocks, and export of plan constraints to your
Quartus® Prime project.
Quartus® Prime Pin Planner GUI, you can identify I/O
banks, VREF groups, and differential pin pairings to help you through the I/O
planning process. Right-click in the Pin Planner spreadsheet interface and click the
Pin Finder to search for specific pins. If migration devices are
selected, the Pin Migration view highlights pins that change function in the migration device
when compared to the currently selected device.
You have the option of importing a Microsoft Excel spreadsheet into the
Quartus® Prime software to start the I/O planning process if you
normally use a spreadsheet in your design flow. You can also export a spreadsheet compatible
(.csv) file containing your I/O assignments when all pins are
When you compile your design in the
Quartus® Prime software, I/O
Assignment Analysis in the Fitter validates that the assignments meet all the device
requirements and generates messages if there are any problems.
Quartus® Prime designers can then pass the pin location
information to PCB designers. Pin assignments between the
Quartus® Prime software and your schematic and board layout tools must match to ensure
the design works correctly on the board where it is placed, especially if changes to the
pin-out must be made. The Pin Planner is integrated with certain PCB design EDA tools and can
read pin location changes from these tools to check the suggested changes. When you compile
your design, the
Quartus® Prime software generates the
.pin file. You can use this file to verify that each pin is correctly
connected in the board schematics.
Early Pin Planning and I/O Assignment Analysis
Table 41. Early Pin Planning and I/O Assignment Analysis Checklist
Use the Create Top-Level Design File
command with I/O Assignment Analysis to check the I/O assignments before the design is
In many design environments, FPGA designers want to plan top-level FPGA I/O pins early so
that board designers can start developing the PCB design and layout. The FPGA device’s I/O
capabilities and board layout guidelines influence pin locations and other types of
assignments. In cases where the board design team specifies an FPGA pin-out, it is crucial
that you verify pin locations in the FPGA place-and-route software as soon as possible to
avoid board design changes.
Starting FPGA pin planning early improves the confidence in early board layouts, reduces the
chance of error, and improves the design’s overall time to market. You can create a
preliminary pin-out for an Intel FPGA using the
Quartus® Prime Pin Planner before the source code is
Early in the design process, the system architect typically has information about the
standard I/O interfaces (such as memory and bus interfaces), IP cores to be used in the
design, and any other I/O-related assignments defined by system requirements.
The Pin Planner Create/Import IP Core feature interfaces with the IP catalog, and enables you
to create or import custom IP cores that use I/O interfaces. Enter PLL and LVDS blocks,
including options such as dynamic phase alignment (DPA), because options affect the pin
placement rules. When you have entered as much I/O-related information as possible, generate a
top-level design netlist file using the Create Top-Level Design File
command in the Pin Planner. You can use the I/O analysis results to change pin assignments or
IP parameters and repeat the checking process until the I/O interface meets your design
requirements and passes the pin checks in the
When planning is complete, the preliminary pin location information can be passed to PCB
designers. When the design is complete, use the reports and messages generated by the
Quartus® Prime Fitter for the final sign-off of the pin assignments.
I/O Features and Pin Connections
Cyclone 10 LP I/O pins are designed for
ease of use and rapid system integration, while simultaneously providing high bandwidth.
Independent modular I/O banks with a common bank structure for vertical migration lend
efficiency and flexibility to the high speed I/O.
The following guidelines provide information pertaining to I/O features and
I/O Signaling Type
Table 42. I/O Signaling Type Checklist
Plan the I/O signaling type based on the system
Allow the software to assign locations for the negative pin in
differential pin pairs.
Cyclone 10 LP devices support a wide range
of industry I/O standards, including single-ended, voltage-referenced single-ended, and
differential I/O standards. Follow these general guidelines when you select a signaling
Single-ended I/O signaling provides a simple rail-to-rail interface. Its speed is limited by
the large voltage swing and noise. Single-ended I/Os do not require termination, unless
reflection in the system causes undesirable effects.
Voltage-referenced signaling reduces the effects of simultaneous switching
outputs (SSO) from pins changing voltage levels at the same time. Voltage-referenced signaling
also provides an improved logic transition rate with a reduced voltage swing, and minimizes
noise caused by reflection with a termination requirement. However, additional termination
components are required for the reference voltage source (VTT).
Differential signaling eliminates the interface performance barrier of single-ended and
voltage-referenced signaling, with superior speed using an additional inverted closely-coupled
data pair. Differential signaling also avoids the requirement for a clean reference voltage.
This is possible because of a lower swing voltage and noise immunity with a common mode noise
rejection capability. Considerations for this implementation include the requirements for a
dedicated PLL to generate a sampling clock, and matched trace lengths to eliminate the phase
difference between an inverted and non-inverted pair.
Cyclone 10 LP I/O pins are organized in
pairs to support differential I/O standards. Each I/O pin pair can support differential input
or output operations, with the exception of certain clock pins that support differential input
operations only. In your design source code, define just one pin to represent a differential
pair, and make a pin assignment for this positive end of the pair. When you specify a
differential I/O standard, the
Quartus® Prime software
automatically places the corresponding negative pin.
Selectable Standards and Flexible I/O Banks
Table 43. Selectable Standards and Flexible I/O Banks Checklist
Select a suitable signaling type and I/O standard for each I/O
Ensure that the appropriate I/O standard support is supported in
the targeted I/O bank.
Place I/O pins that share voltage levels in the same I/O
Verify that all output signals in each I/O bank are intended to
drive out at the bank’s VCCIO voltage level.
Verify that all voltage-referenced signals in each I/O bank are
intended to use the bank’s VREF voltage level.
Check the I/O bank support for LVDS features. Different I/O banks
include different support for LVDS signaling.
Cyclone 10 LP devices have eight I/O banks. All differential
I/O standards are supported in all banks. The only exception is HSTL-12 Class II, which is
only supported in column I/O banks.
You can assign I/O standards and make other I/O-related settings in the Pin
The board must supply each bank with one VCCIO voltage level for every
VCCIO pin in the bank. Each I/O bank is powered by the
VCCIO pins of that particular bank and is independent of the
VCCIO power supply of other I/O banks. A single I/O bank supports output
signals that are driving at the same voltage as the VCCIO power supply. An I/O bank can
simultaneously support any number of input signals with different I/O standards, with some
exceptions for voltage-referenced inputs. Voltage-referenced standards are supported in an I/O
bank using any number of single-ended or differential standards, as long as they use the same
VREF and VCCIO values.
When you use the VREF pins as regular I/Os, they have higher pin capacitance
than regular user I/O pins. This has an impact on the timing if the pins are used as inputs
Dual-Purpose and Special Pin Connections
Table 44. Dual-Purpose and Special Pin Connections Checklist
Make dual-purpose pin settings and check for any restrictions
when using these pins as regular I/O.
Cyclone 10 LP devices allow I/O flexibility with
dual-purpose configuration pins. You can use dual-purpose configuration pins as general I/Os
after device configuration is complete. Select the desired setting for each of the
dual-purpose pins on the Dual-Purpose Pins category of the
Device and Pin Options dialog box. Depending on the configuration
scheme, these pins can be reserved as regular I/O pins, as inputs that are tri-stated, as
outputs that drive ground, or as outputs that drive an unspecified signal.
You can also use dedicated clock inputs, which drive the programmable clock
routing networks, as general-purpose input pins if they are not used as clock pins. When you
use the clock inputs as general inputs, I/O registers use LE-based registers because the clock
input pins do not include dedicated I/O registers.
The device-wide reset and clear pins are available as design I/Os if they are not
Cyclone 10 LP I/O Features
Table 45. Cyclone 10 LP I/O Features
Check available device I/O features that can help I/O interfaces:
current strength, slew rate, I/O delays, open-drain, bus hold, programmable pull-up
resistors, PCI clamping diodes, programmable pre-emphasis, and VOD.
Consider on-chip termination (OCT) features to save board
Verify that the required termination scheme is supported for all
The Cyclone 10 LP IOE offers a range of
programmable features for an I/O pin. These features increase the flexibility of I/O
utilization and provide an alternative to reduce the usage of external discrete components to
on-chip, such as a pull-up resistor and diode.
Intel recommends performing an IBIS or SPICE
simulations to optimize your design settings.
Use the correct dedicated clock pins and routing signals for
clock and global control signals.
Use the device PLLs for clock management.
Analyze input and output routing connections for each PLL and
clock pin. Ensure PLL inputs come from the dedicated clock pins or from another
The first stage in planning your clocking scheme is to determine your system clock
requirements. Understand your device’s available clock resources and correspondingly plan the
design clocking scheme. Consider your requirements for timing performance, and how much logic
is driven by a particular clock.
Cyclone 10 LP devices provide dedicated low-skew and high
fan-out routing networks.
The dedicated clock pins drive the clock network directly, ensuring lower skew than other I/O
pins. Use the dedicated routing network to have a predictable delay with less skew for high
fan-out signals. You can also use the clock pins and clock network to drive control signals
like asynchronous reset.
Connect clock inputs to specific PLLs to drive specific low-skew routing networks. Analyze
the global resource availability for each PLL and the PLL availability for each clock input
Use the following information to help determine which clock networks are
appropriate for the clock signals in your design:
The GCLK networks can drive throughout the entire device, serving as low-skew clock
sources for device logic. This clock region has the maximum delay when compared with to
other clock regions but allows the signal to reach everywhere within the device. This
option is good for routing global reset and clear signals or routing clocks throughout the
IOEs and internal logic can also drive GCLKs to create internally generated GCLKs and
other high fan-out control signals; for example, synchronous or asynchronous clears and
PLLs cannot be driven by internally generated GCLKs. The input clock to the PLL must
come from dedicated clock input pins, fed by a pin-driven dedicated GCLK, or through a
clock control block if the clock control block is fed by an output from another PLL or a
pin-driven dedicated GCLK.
If your system requires more clock or control signals than are available in the target
device, consider cases where the dedicated clock resource could be spared, particularly low
fan-out and low-frequency signals where clock delay and clock skew do not have a significant
impact on the design performance. Use the Global Signal assignment in
Quartus® Prime Assignment Editor to select the type of global
routing, or set the assignment to Off to specify that the signal should
not use any global routing resources.
PLL Feature Guidelines
Table 47. PLL Feature Guidelines Checklist
Enable PLL features and check settings in the parameter
Based on your system requirements, define the required clock frequencies for
your FPGA design, and the input frequencies available to the FPGA. Use these specifications to
determine your PLL scheme. Use the
Quartus® Prime parameter
editor to enter your settings in ALTPLL IP core, and check the results to verify whether
particular features and input/output frequencies can be implemented in a particular PLL.
Cyclone 10 LP device PLLs support several
features for general-purpose clock management including clock feedback modes and
Clock Feedback Mode
Table 48. Clock Feedback Mode Checklist
Ensure you select the correct PLL feedback compensation
Cyclone 10 LP PLLs support five different
clock feedback modes. Each mode compensates for different clock networks and delays so the
clocks are aligned differently.
Table 49. Clock Outputs Checklist
Check that the PLL offers the required number of clock outputs
and use dedicated clock output pins.
You can connect clock outputs to dedicated clock output pins or dedicated clock networks.
There is no dedicated clock out pin for fractional PLL. I/O PLL can connect to a clock network
or a dedicated clock pin.
Clock Control Features
Table 50. Clock Control Features Checklist
Use the clock control block for clock selection and
In Cyclone 10 LP devices, dedicated clock
input pins, PLL counter outputs, dual-purpose clock I/O inputs, and internal logic can all
feed the clock control block for each GCLK. The output from the clock control block, in turn
feeds the corresponding GCLK. The GCLK can drive the PLL input if the clock control block
inputs are outputs of another PLL or dedicated clock input pins.
Reduce the number of pins that switch the voltage level at
exactly the same time whenever possible.
Use differential I/O standards and lower-voltage standards for
Use lower drive strengths for high-switching I/Os. The default
drive strength setting might be higher than your design requires.
Reduce the number of simultaneously switching output pins within
each bank. Spread output pins across multiple banks if possible.
Spread switching I/Os evenly throughout the bank to reduce the
number of aggressors in a given area to reduce SSN (when bank usage is substantially
Separate simultaneously switching pins from input pins that are
susceptible to SSN.
Place important clock and asynchronous control signals near
ground signals and away from large switching buses.
Avoid using I/O pins one or two pins away from PLL power supply
pins for high-switching or high-drive strength pins.
Use staggered output delays to shift the output signals through
time, or use adjustable slew rate settings.
SSN is a concern when too many I/Os (in close proximity) change voltage levels at the same
time. Plan the I/O and clock connections according to the recommendations.
In complex FPGA design development, design practices, coding styles, and IP cores use have an
enormous impact on your device’s timing performance, logic utilization, and system
reliability. In addition, while planning and creating the design, plan for a hierarchical or
team-based design to improve design productivity.
Table 52. Design Recommendations Checklist
Use synchronous design practices. Pay attention to clock
Quartus® Prime Design
Assistant to check design reliability.
In a synchronous design, a clock signal triggers all events. When all of the registers’
timing requirements are met, a synchronous design behaves in a predictable and reliable manner
for all process, voltage, and temperature (PVT) conditions. You can easily target synchronous
designs to different device families or speed grades.
Problems with asynchronous design techniques include reliance on propagation delays in a
device, incomplete timing analysis, and possible glitches. Pay particular attention to your
clock signals, because they have a large effect on your design’s timing accuracy, performance,
and reliability. Problems with clock signals can cause functional and timing problems in your
design. Use dedicated clock pins and clock routing for best results. For clock inversion,
multiplication, and division, use the device PLLs. For clock multiplexing and gating, use the
dedicated clock control block or PLL clock switchover feature instead of combinational logic.
If you must use internally generated clock signals, register the output of any combinational
logic used as a clock signal to reduce glitches. For example, if you divide a clock using
combinational logic, clock the final stage with the clock signal that was used to clock the
The Design Assistant in the
Quartus® Prime software is a
design-rule checking tool that enables you to check for design issues early in the design
flow. The Design Assistant checks your design for adherence to Intel recommended design guidelines or design rules. To run the Design
Assistant, on the Processing menu, point to Start and click
Start Design Assistant. To set the Design Assistant to run
automatically during compilation, turn on Run Design Assistant during
compilation in the Settings dialog box. You can also use
third-party “lint” tools to check your coding styles.
Using IP Cores
Table 53. Using IP Cores Checklist
Use IP cores with the parameter editor.
Intel provides parameterizable IP cores that are
optimized for Intel device architectures. You can
save design time by using IP cores instead of coding your own logic. Additionally, the
Intel-provided IP cores can offer more efficient
logic synthesis and device implementation. You can scale the IP core’s size and set various
options with parameters. IP cores include the library of parameterized modules (LPM) and
Intel device-specific IP cores. You can also take
advantage of Intel and third-party IP cores and
reference designs to save design time. The
Quartus® Prime IP
catalog provides a user interface to customize IP cores. You should build or change IP core
parameters using the parameter editor to ensure you set all ports and parameters
Recommended HDL Coding Styles
Table 54. Recommended HDL Coding Styles Checklist
Follow recommended coding styles, especially for inferring device
dedicated logic such as memory and DSP blocks.
HDL coding styles can have a significant effect on the quality of results for programmable
logic designs. Use Intel’s recommended coding styles
to achieve optimal synthesis results. When designing memory and digital system processing
(DSP) functions, understand the device architecture so you can take advantage of the dedicated
logic block sizes and configurations.
Register Power-Up Levels and Control Signals
Table 55. Register Power-Up Levels and Control Signals Checklist
Enable the chip-wide reset to clear all registers if
Consider resources available for register power-up and control
signals. Do not apply both reset and preset signals to a register.
Cyclone 10 LP devices support an optional chip-wide reset
that enables you to override all clears on all device registers, including the registers of
the memory blocks (but not the memory contents itself). When this DEV_CLRn
pin is driven low, all registers are cleared or reset to 0. If synthesis performs an
optimization called NOT-gate-push back due to register control signals, the affected registers
behave as though they are preset to a high value when DEV_CLRn is driven low.
When the DEV_CLRn pin is driven high, all registers behave as programmed. To
use this chip-wide reset, turn on Enable device-wide reset (DEV_CLRn)
Quartus® Prime software on the
General category of the Device and Pin Options
dialog box before compiling your design.
Each Cyclone 10 LP logic array block (LAB)
also contains dedicated logic for driving register control signals to its LEs. Register
control signals restrict how registers are packed into LABs because signals are shared within
the LAB. It is important that control signals use the dedicated control signals in the device
architecture, so in some cases you might be required to limit the number of different control
signals used in your design.
If the clock signal is not available when reset is asserted, an asynchronous reset is
typically used to reset the logic. The recommended reset architecture allows the reset signal
to be asserted asynchronously and de-asserted synchronously. The source of the reset signal is
then connected to the asynchronous port of the registers, which can be directly connected to
global routing resources. The synchronous de-assertion allows all state machines and registers
to start at the same time. It also avoids the possibility that an asynchronous reset signal is
released at or near the active clock edge of a flipflop, in which case the output of the
flipflop could go to a metastable unknown state.
By default, the
Quartus® Prime integrated synthesis enables the
logic option called Power-Up Don’t Care, which assumes your design does
not depend on the power-up state of the device architecture and allows the software to remove
registers that become stuck high. Other synthesis tools might use similar assumptions.
Designers typically use an explicit reset signal for the design that forces all registers
into their appropriate values after reset but not necessarily at power-up. You can create your
design such that the asynchronous reset allows the board to operate in a safe condition. You
can then bring up the design with the reset active. Thus, you do not have to depend on the
power-up conditions of the device.
If you force a particular power-up condition for your design, use the synthesis options
available in your synthesis tool.
Some synthesis tools can also read the default or initial values for registered signals in
your source code and implement this behavior in the device. For example, the
Quartus® Prime integrated synthesis converts HDL default and initial
values for registered signals into Power-Up Level settings. That way,
the synthesized behavior matches the power-up state of the HDL code during a functional
Registers in the device core always power up to a low (0) logic level in the physical device
architecture. If you specify a high power-up level or a non-zero reset value (often called a
preset signal), synthesis tools typically use the clear signals available on the registers and
perform an optimization referred to as NOT-gate push back.
If you assign a high power-up level to a register that is reset low, or assign a low power-up
value to a register that is preset high, synthesis tools cannot use the NOT-gate push back
optimization technique and might ignore the power-up conditions.
To implement a reset and preset signal on the same register, synthesis tools emulate the
controls with logic and latches that can be prone to glitches because of the different delays
between the different paths to the register. In addition, the power-up value is undefined for
Design Implementation, Analysis, Optimization, and Verification
After you create your design source code and apply constraints including the device selection
and timing requirements, your synthesis tool processes the code and maps it to elements of the
device architecture. The
Quartus® Prime Fitter then performs
placement and routing to implement the design elements in specific device resources. If
required, you can use the
Quartus® Prime software to optimize the
design’s resource utilization and achieve timing closure, preserve the performance of
unchanged design blocks, and reduce compilation time for future iterations. You can also
verify the design functionality with simulation or formal verification. This section provides
guidelines for these stages of the compilation flow.
Selecting a Synthesis Tool
Table 56. Selecting a Synthesis Tool Checklist
Specify your synthesis tool and use the correct supported
Quartus® Prime software includes advanced and easy-to-use
integrated synthesis that fully supports Verilog HDL and VHDL, as well as the Intel hardware description language (AHDL) and schematic
design entry. You can also use industry-leading third-party EDA synthesis tools to synthesize
your Verilog HDL or VHDL design, and then compile the resulting output netlist file in the
Quartus® Prime software. Specify a third-party synthesis tool
in the New Project Wizard or the EDA Tools Settings page of the
Settings dialog box to use the correct Library Mapping File
(.lmf) for your synthesis netlist.
Intel recommends using the most recent version of
third-party synthesis tools, because tool vendors are continuously adding new features, fixing
tool issues, and enhancing performance for Intel
Different synthesis tools can give different results. If you want to select the
best-performing tool for your application, you can experiment by synthesizing typical designs
for your application and coding style and comparing the results. Be sure to perform placement
and routing in the
Quartus® Prime software to get accurate timing
analysis and logic utilization results.
Your synthesis tool might offer the capability to create a
Quartus® Prime project and pass constraints such as the EDA tool setting, device
selection, and timing requirements that you specified in your synthesis project. You can use
this capability to save time when setting up your
project for placement and routing.
Review resource utilization reports after compilation.
After compilation in the
Quartus® Prime software, review the
device resource utilization information to determine whether the future addition of extra
logic or other design changes introduce fitting difficulties. If your compilation results in a
no-fit error, resource utilization information is important so you can analyze the fitting
problems in your design.
To determine resource usage, refer to the Flow Summary section of the
Compilation Report for a percentage representing the total logic utilization, which includes
an estimation of resources that cannot be used due to existing connections or logic use.
More detailed resource information is available by viewing the reports under
Resource Section in the Fitter section of the Compilation Report. The Fitter Resource Usage Summary report breaks down the logic utilization information and
indicates the usage of LEs, and provides other resource information including the number of
bits in each type of memory block. There are also reports that describe some of the
optimizations that occurred during compilation. For example, if you use the
Quartus® Prime integrated synthesis, the reports under the Optimization Results folder in the Analysis & Synthesis section provide information, including registers that
were removed during synthesis. Use this report to estimate device resource utilization for a
partial design to ensure that registers were not removed due to missing connections with other
parts of the design.
Quartus Prime Messages
Quartus® Prime Messages Checklist
Quartus® Prime messages,
especially warning or error messages.
Each stage of the compilation flow generates messages, including informational notes,
warnings, and critical warnings. Review these messages to check for any design problems.
Ensure that you understand the significance of any warning messages, and make changes to the
design or settings if required. In the
Quartus® Prime user
interface, you can use the Message window tabs to look at only certain
types of messages, and you can suppress messages if you have determined that they do not
require any action from you.
Timing Constraints and Analysis
Table 59. Design Specifications Checklist
Ensure timing constraints are complete and accurate, including
all clock signals and I/O delays.
Review the TimeQuest Timing Analyzer reports after compilation to
ensure there are no timing violations.
Ensure that the input I/O times are not violated when data is
provided to the Cyclone 10 LP device.
In an FPGA design flow, accurate timing constraints allow timing-driven synthesis software
and place-and-route software to obtain optimal results. Timing constraints are critical to
ensure designs meet their timing requirements, which represent actual design requirements that
must be met for the device to operate correctly. The
Quartus® Prime software optimizes and analyzes your design using different timing models for each device
speed grade, so you must perform timing analysis for the correct speed grade. The final
programmed device might not operate as expected if the timing paths are not fully constrained,
analyzed, and verified to meet requirements.
Quartus® Prime software includes the
Quartus® Prime TimeQuest Timing Analyzer, a powerful ASIC-style timing
analysis tool that validates the timing performance of all logic in your design. It supports
the industry standard Synopsys Design Constraints (SDC) format timing constraints, and has an
easy-to-use GUI with interactive timing reports. It is ideal for constraining high-speed
source-synchronous interfaces and clock multiplexing design structures.
The software also supports static timing analysis in the industry-standard Synopsys Primetime
software. Specify the tool in the New Project Wizard or the EDA Tools
Settings page of the Settings dialog box to generate the
required timing netlist.
A comprehensive static timing analysis includes analysis of register to register, I/O, and
asynchronous reset paths. It is important to specify the frequencies and relationships for all
clocks in your design. Use input and output delay constraints to specify external device or
board timing parameters. Specify accurate timing requirements for external interfacing
components to reflect the exact system intent.
The TimeQuest Timing Analyzer performs static timing analysis on the entire system, using
data required times, data arrival times, and clock arrival times to verify circuit performance
and detect possible timing violations. It determines the timing relationships that must be met
for the design to correctly function.
You can use the report_datasheet command to generate a datasheet report that
summarizes the I/O timing characteristics of the entire design.
Recommended Timing Optimization and Analysis Assignments
Table 60. Recommended Timing Optimization and Analysis Assignments
Turn on Optimize multi-corner timing on
the Fitter Settings page in the Settings
Use create_clock and
create_generated_clock to specify the frequencies and relationships
for all clocks in your design.
Use set_input_delay and
set_output_delay to specify the external device or board timing
Use derive_pll_clocks to create generated clocks
for all PLL outputs, according to the settings in the PLL IP cores. Specify multicycle
relationships for LVDS transmitters or receiver deserialization factors.
Use derive_clock_uncertainty to automatically
apply inter-clock, intra-clock, and I/O interface uncertainties.
Use check_timing to generate a report on any
problem with the design or applied constraints, including missing constraints.
These assignments and settings are important for large designs such as those
in Cyclone 10 LP devices.
When you turn on the Optimize multi-corner
timing option, the design is optimized to meet its timing requirements at all
timing process corners and operating conditions. Therefore, turning on this option helps
create a design implementation that is more robust across PVT variations.
In your TimeQuest Timing Analyzer .sdc constraints file, apply the
recommended constraints to your design.
Area and Timing Optimization
Table 61. Area and Timing Optimization Checklist
Perform Early Timing Estimation if you want timing estimates
before running a full compilation.
Quartus® Prime optimization
features to achieve timing closure or improve the resource utilization.
Use the Timing and Area Optimization Advisors to suggest
This section highlights some of the features offered in the
Quartus® Prime software to help optimize area (or resource utilization) and timing
performance. If the timing analysis reports that your design requirements were not met, you
must make changes to your design or settings and recompile the design to achieve timing
closure. If your compilation results in no-fit messages, you must make changes to get
successful placement and routing.
You can use the Early Timing Estimation feature to estimate your design’s timing results
before the software performs full placement and routing. On the Processing menu, point to
Start and click Start Early Timing Estimate to
generate initial compilation results after you have run analysis and synthesis.
Physical synthesis optimizations make placement-specific changes to the netlist that improve
results for a specific Intel device. You can optimize
for performance and fitting in the Physical Synthesis Optimizations
page of the Settings dialog box. The options in the Physical
Synthesis Optimizations page typically increase compilation time significantly
but can provide significant improvements to the quality of results with push-button
optimizations. If you turn on these options, ensure that they do improve the results for your
design. If you do not require these options to meet your design timing requirements, turn off
the options to reduce the compilation time.
The Design Space Explorer (DSE) is a utility that automates the process of finding the
optimal collection of the
Quartus® Prime software settings for
your design. The Search for Best Performance and Search for
Best Area options under Exploration Settings use a
predefined exploration space to target design performance or area improvements with multiple
compilations. You can also set the Optimization Goal to
Optimize for Speed or Optimize for Area using
the Advanced tab in the DSE window.
The Optimization Advisors provide guidance in making settings that optimize your design. On
the Tools menu, point to Advisors and click Resource
Optimization Advisor or Timing Optimization Advisor.
Evaluate the options and choose the settings that best suit your requirements.
Preserving Performance and Reducing Compilation Time
Table 62. Preserving Performance and Reducing Compilation Time Checklist
Use incremental compilation to preserve performance for unchanged
blocks in your design and to reduce compilation times.
Ensure parallel compilation is enabled if you have multiple
processors available for compilation.
Use the Compilation Time Advisor to suggest settings that reduce
Use the incremental compilation feature to preserve logic in unchanged parts of your design,
preserve timing performance, and reach timing closure more efficiently. You can speed up
design iteration time by an average of 60% when making changes to the design with the
incremental compilation feature.
Quartus® Prime software can run some algorithms in parallel
to take advantage of multiple processors and reduce compilation time when more than one
processor is available to compile the design. Set the Parallel
compilation option on the Compilation Process Settings
page of the Settings dialog box, or change the default setting in the
Options dialog box in the Processing page from
the Tools menu.
The Compilation Time Advisor provides guidance in making settings that reduce your design
compilation time. On the Tools menu, point to Advisors and click
Compilation Time Advisor. Using some of these techniques to reduce
compilation time can reduce the overall quality of results.
Table 63. Simulation Checklist
Specify your simulation tool, and use the correct supported
version and simulation models.
Quartus® Prime software supports both RTL
and gate level functional simulations. Perform functional simulation at the beginning of your
design flow to check the design functionality or logical behavior of each design block. You do
not have to fully compile your design; you can generate a functional simulation netlist that
does not contain timing information.
Intel provides the ModelSim® - Intel
FPGA Starter Edition and offers the higher-performance ModelSim® - Intel FPGA Edition, which enable
you to take advantage of advanced testbench capabilities and other features. In addition, the
Quartus® Prime EDA Netlist Writer can generate timing netlist
files to support other third-party simulation tools such as Synopsys VCS, Cadence NC-Sim, and
Aldec Active-HDL. Specify your simulation tool in the EDA Tools
Settings page of the Settings dialog box to
generate the appropriate output simulation netlist. The software can also generate scripts to
help you setup libraries in your tool with NativeLink integration.
If you use a third-party simulation tool, use the software version that is supported with
Quartus® Prime software version. The
Quartus® Prime Software Release Notes list the version of each
simulation tool that is officially supported with that particular version of the
Quartus® Prime software. Use the model libraries provided with your
Quartus® Prime software version, because libraries can change
between versions, which might cause a mismatch with your simulation netlist. To create a
testbench, on the Processing menu, point to Start and click
Start Testbench Template Writer.
Table 64. Power Analysis Checklist
After compilation, analyze power consumption and heat dissipation
in the Power Analyzer.
Provide accurate signal activities, preferably with a gate-level
simulation .vcd, to get accurate power analysis
Specify the correct operating conditions for power
Before design completion, estimate power consumption using the EPE
spreadsheet. After compiling your design, analyze the power consumption and heat dissipation
Quartus® Prime Power Analyzer to ensure the design has
not violated power supply and thermal budgets.
You must compile a design (to provide information about design resources,
placement and routing, and I/O standards) and provide signal activity data (toggle rates and
static probabilities) to use the Power Analyzer. You can derive signal activity data from
simulation results or a user-defined default toggle rate and vectorless estimation. The signal
activities used for analysis must be representative of the actual operating behavior. For the
most accurate power estimation, use gate-level simulation results with a .vcd output file from a third-party simulation tool. The
simulation activity should include typical input vectors over a realistic time period and not
the corner cases often used during functional verification. Use the recommended simulator
settings (such as glitch filtering) to ensure good results.
You must also specify operating conditions, including the core voltage, device power
characteristics, ambient and junction temperature, cooling solution, and the board thermal
model. Select the appropriate settings on the Operating Settings and
Conditions page in the Settings dialog box.
To calculate the dynamic, static, and I/O thermal power consumption, on the
Processing menu, click Power Analyzer Tool. The tool
also provides a summary of the signal activities used for analysis and a confidence metric
that reflects the overall quality of the data sources for signal activities.
The report is a power estimate based on the data provided, and is not a power specification.
Always refer to the datasheet for the power specification of your device.
Cyclone 10 LP devices use architectural
power reduction techniques to minimize power and deliver high performance. To reduce dynamic
power consumption in Cyclone 10 LP devices, you can use
various design and software techniques to optimize your design.
Power optimization in the
Quartus® Prime software depends on
accurate power analysis results. Use the guidelines in the previous section to ensure the
software optimizes the power utilization correctly for the design’s operating behavior and
Device and Design Power Optimization Techniques
Table 65. Device and Design Power Optimization Techniques Checklist
Use recommended design techniques and
Quartus® Prime options to optimize your design for power consumption, if
Use the Power Optimization Advisor to suggest optimization
Clock Power Management
Table 66. Clock Power Management Checklist
Optimize the clock power management.
Clocks represent a significant portion of dynamic power consumption, because
of their high switching activity and long paths. The
Quartus® Prime software automatically optimizes clock routing power by enabling only the portions of a
clock network that are required to feed downstream registers. You can also use clock control
features to dynamically enable or disable the clock network. When a clock network is powered
down, all the logic fed by that clock network does not toggle, thereby reducing the overall
power consumption of the device.
To reduce LAB-wide clock power consumption without disabling the entire clock tree, use the
LAB-wide clock enable signal to gate the LAB-wide clock. The
Quartus® Prime software automatically promotes register-level clock enable signals to
the LAB level.
Memory Power Reduction
Table 67. Memory Power Reduction Checklist
Reduce the number of memory clocking events.
Reduce the number of memory clocking events to reduce memory power consumption. You can use
clock gating or the clock enable signals in the memory ports.
I/O Power Guidelines
Table 68. I/O Power Guidelines Checklist
Review the I/O power guidelines.
The dynamic power consumed in the I/O buffer is proportional to the total load capacitance;
therefore, lower capacitance reduces power consumption.
Non-terminated I/O standards such as LVTTL and LVCMOS have a rail to-rail output swing equal
to the VCCIO supply voltage. Because dynamic power is proportional to the square of
the voltage, use lower voltage I/O standards to reduce dynamic power. These I/O standards
consume little static power.
Because dynamic power is also proportional to the output transition frequency, use
resistively-terminated I/O standards such as SSTL for high-frequency applications. The output
load voltage swings by an amount smaller than the VCCIO around a bias point;
therefore, dynamic power is lower than for non-terminated I/O under similar conditions.
Resistively-terminated I/O standards dissipate significant static power because current is
constantly driven into the termination network. Use the lowest drive strength that meets your
speed and waveform requirements to minimize static power when using resistively terminated I/O
The power used by external devices is not included in the EPE calculations,
so be sure to include it separately in your system power calculations.
Quartus Prime Power Optimization Techniques
Quartus® Prime Power Optimization
Review recommended design techniques and
Quartus® Prime options to optimize power consumption.
Use the Power Optimization Advisor to suggest optimization settings.
Quartus® Prime software offers
power-optimized synthesis and fitting to reduce core dynamic power.
Optimizing your design for area saves power because fewer logic blocks are
used; therefore typically less switching activity. You can use the DSE and Power Optimization
Advisor to provide additional suggestions to reduce power.
Quartus® Prime software includes the Power
Optimization Advisor, which provides specific power optimization advice and recommendations
based on the current design project settings and assignments. On the Tools menu, point to
Advisors and click Power
Optimization Advisor. After making any of the recommended changes, recompile
your design and run the Power Analyzer to check the change in your power results.