External Memory Interfaces (EMIF) IP User Guide: Agilex™ 3 FPGAs and SoCs

ID 847458
Date 4/24/2025
Public
Document Table of Contents

3.3.1. Configuring DQ Pin Swizzling

It is important to strictly follow the pin placement for a given memory topology when assigning pin locations for your EMIF IP.

Do not change the location for the EMIF pin using a .qsf assignment or the pin planner if you need to swap the DQ pins within a DQS group or the DQS group to simplify board design. For example, if you implement a x32 LPDDR4 interface, the EMIF pin location must adhere to the x32 column in the LPDDR4 Pin Placement table in the Agilex 3 FPGA EMIF IP Pin and Resource Planning chapter. There is no flexibility to swap the address command pin location.

The following tables summarize the parameters for pin swizzling and byte swizzling, respectively.

Table 14.  Parameters for Pin Swizzling
Parameter Description
PIN_SWIZZLE_CH<m>_DQS<n>

Used for swizzling DQ pin within DQS group <n> for channel <m>.

For LPDDR4 device widths of x16, you can swizzle each DQ pin within the lower byte and upper byte respectively. You cannot swizzle DQ pin for the lower byte to upper byte and vice versa.

Table 15.  Parameters for Byte Swizzling
Parameter Description
BYTE_SWIZZLE_CH<m>

Used for swizzling DQS group for CH<m> of the interface.