External Memory Interfaces (EMIF) IP User Guide: Agilex™ 5 FPGAs and SoCs

ID 817467
Date 11/18/2024
Public
Document Table of Contents

6.3.3.5. Specific Pin Connection Requirements

PLL

  • You must constrain the PLL reference clock to the address and command sub-bank only.
  • You must constrain differential reference clocks to pin indices 0 and 1 in lane AC2.
  • The sharing of PLL reference clocks across multiple interfaces is permitted; however, pin indices 0 and 1 of lane 2 of the address and command sub-bank for all slave EMIF interfaces can be used only for supplying reference clocks. Altera recommends that you consider connecting these clock input pins to a reference clock source to facilitate greater system implementation flexibility.
Note: Agilex™ 5 FPGAs do not support single-ended I/O PLL reference clocks for EMIF IP.

OCT

  • For DDR4, you must constrain the RZQ pin to pin index 2 in lane AC2.
  • Every EMIF instance requires its own dedicated RZQ pin.
  • The sharing of RZQ pins is not permitted.

Address and Command

  • For DDR4, you must constrain the ALERT_N pin to the address and command lanes only.
  • In three-lane address and command schemes, you can place the ALERT_N pin at pin index 8 in lane AC2 only.
  • In four-lane address and command schemes, you can place the ALERT_N pin at pin index 8 in lane AC2 or at pin index 8 in lane AC3. When you generate the IP, the resulting RTL specifies which connection to use.

DQS/DQ/DM

For DDR4 x8 DQS grouping, the following rules apply:

  • You may use pin indices 0, 1, 2, 3, 8, 9, 10, and 11 within a lane for DQ mode pins only.
  • You must use pin index 4 for the DQS_T pin only.
  • You must use pin index 5 for the DQS_C pin only.
  • You must ensure that pin index 7 remains unused. Pin index 7 is not available for use as a general purpose I/O.
  • You must use pin index 6 for the DM/DBI_N pin only.

For DDR4 x4 DQS grouping, the following rules apply:

  • You may use pin indices 0, 1, 2, and 3 within a lane for DQ mode pins for the lower nibble only. Pin rotation within this group is permitted.
  • You must use pin index 4 for the DQS_T pin only of the lower nibble.
  • You must use pin index 5 for the DQS_C pin only of the lower nibble.
  • You may use pin indices 8, 9, 10, and 11 within a lane for the DQ mode pins only for the upper nibble.
  • Pin rotation within this group is permitted.
  • You must use pin index 6 for the DQS_T pin only of the upper nibble.
  • You must use pin index 7 for the DQS_C pin only of the upper nibble.