External Memory Interfaces (EMIF) IP User Guide: Agilex™ 5 FPGAs and SoCs
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Visible to Intel only — GUID: reo1682726173632
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6.4.3. DDR4 Interface x8 Data Lane
For DDR4 interfaces composed of ×8 devices, two pins are reserved for DQS_T and DQS_C signals, one pin is reserved for the optional DM/DBI signal, one pin must be reserved, and the remaining eight pins are for DQ signals. One-byte data lane must be assigned for each byte lane, where the byte lane covers DQ [0:7], DQS_T/DQS_C and DBI_N. The following are EMIF I/O pin swapping restrictions applicable to a DDR4 interface with a ×8 data lane:
- DQS_T must go to pin 4 in IO12 pins.
- DQS_C must go to pin 5 in IO12 pins.
- DBI_N must go to pin 6 in IO12 pins. If the interface does not use the DBI_N pin, this pin 6 in IO12 lane must remain unconnected.
- Pin 7 in IO12 lane remains unconnected. Altera recommends that you connect this pin 7 to the TDQS dummy load of the memory component and route it as a differential trace along with DBI_N (pin 6). This facilitates ×4 or ×8 data interoperability in DIMMs configuration.
- You can connect data byte (DQ [0:7]) to any pins [0,1,2,3,8,9,10,11] in the byte lane. Any permutation within selected pins is permitted.
Pin Index Within Byte Lane | DDR4 x8 Data Lane Function | Swap Consideration |
---|---|---|
0 | DQ Pin | Swap group A |
1 | DQ Pin | Swap group A |
2 | DQ Pin | Swap group A |
3 | DQ Pin | Swap group A |
4 | DQS-T Pin | Fixed location (not swappable) |
5 | DQS-C Pin | Fixed location (not swappable) |
6 | DM/DBI Pin | Fixed location (not swappable) |
7 | Unused | Fixed location (not swappable) |
8 | DQ Pin | Swap group A |
9 | DQ Pin | Swap group A |
10 | DQ Pin | Swap group A |
11 | DQ Pin | Swap group A |