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

ID 772632
Date 12/04/2023
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2.3.5. Example: Byte Swizzling for Lockstep Configuration

In lockstep configuration, a DQ lane with a letter s prefix is used as RUSER/WUSER or ECC lane. This lane corresponds to the ECC lane in byte-swizzling notation; it cannot be swapped with other DQS lanes.

Case A: DDR4/DDR5 x40 with sDQ[0]

sDQ[0] maps to the RUSER/WUSER group. It corresponds to the ECC lane in byte-swizzling notation. Because the BYTE_SWIZZLE_CH0 specification can only accept 0,1,2,3,ECC and X, the group number for other DQS groups must be reduced by 1.

This example illustrates the swizzling of DQS group 3 (BL0) with DQS group 2 (BL1), and DQS group 1 (BL2) with DQS group 0 (BL3), respectively.

Table 12.  Byte Swizzling for Case A
Scheme BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
DDR4/5_AC_TOP DQ[4] DQ[3] DQ[2] DQ[1] AC1 Ac2 AC0 sDQ[0]
DQS group number in byte swizzling notation 3 2 1 0 X X X ECC
After Byte Swizzling 2 3 0 1 X X X ECC

To achieve the swizzling described in the above table, enter the following BYTE_SWIZZLE_CH0 specification in User Extra Parameters:

BYTE_SWIZZLE_CH0=2,3,0,1,X,X,X,ECC;

The method to swizzle the DQ pin within a group is the same for lockstep and non-lockstep configuration. Refer to the DQ Pin Swizzling Within DQS group for x32 DDR4 interface example for more information on how to configure DQ Pin Swizzling.

Case B: DDR4/DDR5 x40 with sDQ[4]

sDQ[4] maps to RUSER/WUSER group. It corresponds to the ECC lane in byte-swizzling notation.

Table 13.  Byte Swizzling for Case B
Scheme BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
DDR4/5_AC_BOT DQ[0] AC0 AC1 AC2 DQ[1] DQ[2] DQ[3] sDQ[4]
DQS group number in byte swizzling notation 0 X X X 1 2 3 ECC
After Byte Swizzling 1 X X X 0 3 2 ECC

This example illustrates the swizzling of DQS group 0 (BL0) with DQS group 1 (BL4), and DQS group 2 (BL5) with DQS group 3 (BL6), respectively.

To achieve this swizzling, enter the following BYTE SWIZZLE CH0 specification in User Extra Parameters:

BYTE_SWIZZLE_CH0=1,X,X,X,0,3,2,ECC;

The method to swizzle the DQ pin within a group is the same for lockstep and non-lockstep configurations. For more information on how to configure DQ pin swizzling, refer to the DQ Pin Swizzling Within DQS group for x32 DDR4 interface example.

Case C: DDR4 x72 Lockstep Implemented with AC Pri Top Sub-Bank / Sec DQ Bot

sDQ[0] maps to RUSER/WUSER group. It corresponds to the ECC lane in byte-swizzling notation.

Table 14.  Byte Swizzling for DDR4 x72 Implemented with AC Pri Top Sub-Bank / Sec DQ Bot
  BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
  Primary
Default Placement DQ[4] DQ[3] DQ[2] DQ[1] AC1 AC2 AC0 sDQ[0]
DQS group number in byte swizzling notation 3 2 1 0 X X X ECC
After Byte Swizzling 3 2 0 1 X X X ECC
  Secondary
Default Placement DQ[8] DQ[7] DQ[6] DQ[5] GPIO GPIO GPIO GPIO
DQS group number in byte swizzling notation 7 6 5 4 X X X X
After Byte Swizzling 6 7 4 5 X X X X

In the above table, the After Byte Swizzling rows denote the DQS group implemented in the lane after the swizzling. To achieve the swizzling, enter the following parameter in User Extra Parameters:

BYTE_SWIZZLE_PRI=3,2,0,1,X,X,X,ECC;
BYTE_SWIZZLE_SEC=6,7,4,5,X,X,X,X;

As this configuration is implemented using two IO96 banks, and the ECC lane is placed on the primary IO96 bank, specify the pin swizzling information for the ECC lane using PIN_SWIZZLE_PRI_ECC, if you want to swizzle the DQ pins within the ECC lane.

Case D: DDR4 x72 Lockstep Implemented with AC Pri Bot Sub-Bank / Sec DQ Bot

Table 15.  Byte Swizzling for DDR4 x72 Implemented with AC Pri Bot Sub-Bank / Sec DQ Bot
  BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
  Primary
Default Placement DQ[0] AC0 AC1 AC2 DQ[1] DQ[2] DQ[3] sDQ[4]
DQS group number in byte swizzling notation 0 X X X 1 2 3 ECC
After Byte Swizzling 0 X X X 1 3 2 ECC
  Secondary
Default Placement DQ8 DQ7 DQ6 DQ5 GPIO GPIO GPIO GPIO
DQS group number in byte swizzling notation 7 6 5 4 X X X X
After Byte Swizzling 7 6 4 5 X X X X

In the above table, the After Byte Swizzling rows denote the DQS group implemented in the lane after the swizzling. To achieve the swizzling, enter the following parameter in User Extra Parameters:

BYTE_SWIZZLE_PRI=0,X,X,X,1,3,2,ECC;
BYTE_SWIZZLE_SEC=7,6,4,5,X,X,X,X;

As this configuration is implemented using two IO96 banks, and the ECC lane is placed on the primary IO96 bank, specify the pin swizzling information for the ECC lane using PIN_SWIZZLE_PRI_ECC, if you want to swizzle the DQ pins within the ECC lane.

Case E: DDR4 x72 Lockstep Implemented with AC Pri Top Sub-Bank / Sec DQ Bot(m)

Table 16.  Byte Swizzling for DDR4 x72 Implemented with AC Pri Top Sub-Bank / Sec DQ Bot(m)
  BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
  Primary
Default Placement DQ[3] DQ[2] DQ[1] DQ[0] AC1 AC2 AC0 AC3
DQS group number in byte swizzling notation 3 2 1 0 X X X X
After Byte Swizzling 2 3 0 1 X X X X
  Secondary
Default Placement DQ[8] DQ[7] DQ[6] DQ[5] X X GPIO sDQ[4]
DQS group number in byte swizzling notation 7 6 5 4 X X X ECC
After Byte Swizzling 4 5 6 7 X X X ECC

In the above table, the After Byte Swizzling rows denote the DQS group implemented in the lane after the swizzling. To achieve the swizzling, enter the following parameter in User Extra Parameters:

BYTE_SWIZZLE_PRI=2,3,0,1,X,X,X,X;
BYTE_SWIZZLE_SEC=4,5,6,7,X,X,X,ECC;

As this configuration is implemented using two IO96 banks, and the ECC lane is placed on the secondary IO96 bank, specify the pin swizzling information for the ECC lane using PIN_SWIZZLE_SEC_ECC, if you want to swizzle the DQ pins within the ECC lane.

Case F: DDR4 x64 Lockstep SODIMM (with x4 Memory Component) Implemented with AC Pri Top Sub-Bank / Sec DQ Bot

Table 17.  Byte Swizzling for DDR4 x72 Implemented with AC Pri Top Sub-Bank / Sec DQ Bot(m)
  BL0 BL1 BL2 BL3 BL4 BL5 BL6 BL7
  Primary
Default Placement DQ0 DQ3 DQ2 DQ1 AC1 AC2 AC0 X
DQS bundle in byte swizzling notation 3 2 1 0 X X X X
After Byte Swizzling 2 3 0 1 X X X X
  Secondary
Default Placement DQ7 DQ6 DQ5 DQ4 X X X X
DQS bundle in byte swizzling notation 7 6 5 4 X X X X
After Byte Swizzling 7 6 5 4 X X X X

In the above table, the After Byte Swizzling rows denote the DQS bundle implemented in the lane after the swizzling. To achieve the swizzling in the primary IO96 bank, enter the following parameter in User Extra Parameters:

BYTE_SWIZZLE_PRI= 2,3,0,1,X,X,X,X;

For x4 device widths, the values in BYTE_SWIZZLE represent the bundles of 2 x4 DQS groups. The lower DQS group of the bundle is connected to the lower half of the byte lane, while the upper DQS group of the bundle is connected to the upper half of the byte lane.

The placement of each DQS bundle and DQS group in this example, after the byte swizzling, follows the pattern shown below:

  • CH0 Bundle 0 is placed on BL2 in the Primary IO96
    • CH0 DQS0 connected to lower half of BL2
    • CH0 DQS1 connected to upper half of BL2
  • CH0 Bundle 1 is placed on BL3 in the Primary IO96
    • CH0 DQS2 connected to lower half of BL3
    • CH0 DQS3 connected to upper half of BL3
  • CH0 Bundle 2 is placed on BL0 in the Primary IO96
    • CH0 DQS4 connected to lower half of BL0
    • CH0 DQS5 connected to upper half of BL0
  • CH0 Bundle 3 is placed on BL1 in the Primary IO96
    • CH0 DQS6 connected to lower half of BL1
    • CH0 DQS7 connected to upper half of BL1
  • CH0 Bundle 4 is placed on BL3 in the Secondary IO96
    • CH0 DQS8 connected to lower half of BL3
    • CH0 DQS9 connected to upper half of BL3

In this case, only four values are required to specify the pin swizzling information for a x4 DQS group.

Example:

  • PIN_SWIZZLE_PRI_DQS0=3,2,0,1;
  • PIN_SWIZZLE_PRI_DQS1=7,6,5,4;
  • PIN_SWIZZLE_PRI_DQS6=24,25,26,27;
  • PIN_SWIZZLE_PRI_DQS7=28,29,30,31;
  • PIN_SWIZZLE_SEC_DQS14=59,57,58,56;
  • PIN_SWIZZLE_SEC_DQS15=63,60,61,62;