AN 796: Cyclone® V and Arria® V SoC Device Design Guidelines

ID 683360
Date 3/30/2022
Document Table of Contents
Give Feedback

3.2. Design Considerations for Connecting Device I/O to HPS Peripherals and Memory

One of the most important considerations when configuring the HPS is to understand how the I/O is organized in the Cyclone® V/ Arria® V SoC devices. The HPS I/O is physically divided into:
  • HPS Column I/O: Contains the HPS Dedicated Function Pins and HPS Dedicated I/O with loaner capability
  • HPS Row I/O: Contains the HPS External Memory Interface (EMIF) I/O and HPS General Purpose Input (GPI) pins
Figure 2. Example layout for HPS Column I/O and HPS Row I/O in Cyclone® V SX and ST device
Note: For more information regarding the I/O pin layout, refer to the appropriate "I/O Features" chapter in the Cyclone® V or Arria® V Device Handbook, Volume 1: Device Interfaces and Integration.
Table 6.  HPS I/O Pin Type Summary
Pin Type Purpose
HPS Dedicated Function Pins Each I/O has only one function and cannot be used for other purposes.
HPS Dedicated I/O with loaner capability These I/Os are primarily used by the HPS, but can be used on an individual basis by the FPGA if the HPS is not using them.
HPS External Memory Interface (EMIF) I/O These I/Os are used for connecting to the HPS external memory interface (EMIF). Refer to the "External Memory Interface in Cyclone® V Devices" or "External Memory Interface in Arria® V Devices" chapter in the respective device handbook for more information regarding the layout of these I/O pins.
HPS General Purpose Input (GPI) Pins These pins are also known as HLGPI pins. These input-only pins are located in the same bank as the HPS EMIF I/O. Note that the smallest Cyclone V SoC package U19 (484 pins) does not have any HPS GPI pins.
FPGA I/O These are general purpose I/O that can be used for FPGA logic and FPGA External Memory Interfaces.

The table below summarizes the characteristics of each I/O type.

Table 7.  I/O Types
  HPS Dedicated Function Pins HPS Dedicated I/O with loaner capability HPS External Memory Interface HPS General Purpose Input FPGA I/O
Number of Available I/O 11 Up to 67 ( Cyclone® V SoC) and 94 ( Arria® V SoC) Up to 86 14 (except for Cyclone® V SoC U19 package ) Up to 288 ( Cyclone® V SoC) and Up to 592 ( Arria® V SoC)
Voltages Supported 3.3V, 3.0V, 2.5V, 1.8V, 1.5V 3.3V, 3.0V, 2.5V, 1.8V, 1.5V LVDS I/O for DDR3, DDR2 and LPDDR2 protocols Same as the I/O bank voltage used for HPS EMIF 3.3V, 3.0V, 2.5V, 1.8V, 1.5V, 1.2V
Purpose Clock, Reset, HPS JTAG Boot source, High speed HPS peripherals Connect to SDRAM General Purpose Input General Purpose I/O
Timing Constraints Fixed Fixed Fixed for legal combinations Fixed User defined
Recommended Peripherals JTAG QSPI, NANDx8, eMMC, SD/MMC, UART, USB, EMAC DDR3, DDR2 and LPDDR2 SDRAM GPI Slow speed peripherals (I2C, SPI, EMAC-MII)
Note: You can access the timing information to perform off-​chip analysis by reviewing the HPS timing in the Cyclone® V Device Datasheet or Arria® V Device Datasheet.