External Memory Interfaces Agilex™ 7 M-Series FPGA IP Design Example User Guide

ID 772632
Date 7/08/2024
Public

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2.3.1. Example: DQ Pin Swizzling Within DQS group for x32 DDR4 interface

Example: DQ Pin Swizzling Within DQS group for x32 DDR4 interface

This example uses the lane placement of the following table, using a memory device of x8 width.

Table 5.  Lane Placement for a x32 DDR4 Interface
Lane Number BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
Default placement DQ[0] AC0 AC1 AC2 DQ[1] DQ[2] DQ[3] GPIO
Table 6.  Example of Swizzling DQ pin in BL0 ( DQS group 0)
Lane Pin Index DDR4 x32 (Default Placement) After Swizzling / Swapping
BL0 11 MEM_DQ[7] MEM_DQ[6]
10 MEM_DQ[6] MEM_DQ[5]
9 MEM_DQ[5] MEM_DQ[7]
8 MEM_DQ[4] MEM_DQ[4]
7    
6 MEM_DM_N[0] MEM_DM_N[0]
5 MEM_DQS_C[0] MEM_DQS_C[0]
4 MEM_DQS_T[0] MEM_DQS_T[0]
3 MEM_DQ[3] MEM_DQ[0]
2 MEM_DQ[2] MEM_DQ[2]
1 MEM_DQ[1] MEM_DQ[1]
0 MEM_DQ[0] MEM_DQ[3]

To achieve this swizzling in DQS group 0, you must enter PIN_SWIZZLE_CH0_DQS0=3,1,2,0,4,7,5,6; in the User Extra Parameters field of the Additional Parameters tab in the Advanced Parameters section of the General IP Parameters tab in the External Memory Interfaces IP parameter editor.

Figure 26. Entering a PIN_SWIZZLE Specification
Table 7.  Example of Swizzling DQ pin in BL5 ( DQS group 2)
Lane Pin Index DDR4 x32 (from table) After Swizzling / Swapping
BL5 71 MEM_DQ[23] MEM_DQ[17]
70 MEM_DQ[22] MEM_DQ[22]
69 MEM_DQ[21] MEM_DQ[21]
68 MEM_DQ[20] MEM_DQ[20]
67    
66 MEM_DM_N[2] MEM_DM_N[2]
65 MEM_DQS_C[2] MEM_DQS_C[2]
64 MEM_DQS_T[2] MEM_DQS_T[2]
63 MEM_DQ[19] MEM_DQ[19]
62 MEM_DQ[18] MEM_DQ[18]
61 MEM_DQ[17] MEM_DQ[23]
60 MEM_DQ[16] MEM_DQ[16]

To achieve this swizzling in DQS Group 2, you must enter PIN_SWIZZLE_CH0_DQS2=16,23,18,19,20,21,22,17; in the User Extra Parameters field of the Additional Parameters tab in the Advanced Parameters section of the General IP Parameters tab in the External Memory Interfaces IP parameter editor.

Figure 27. Entering a PIN_SWIZZLE Specification

You can enter multiple specifications in the User Extra Parameters field, each separated by a comma.

Figure 28. Entering Multiple PIN_SWIZZLE Specifications