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

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

A.1.5. Agilex™ 3 EMIF Architecture: Input DQS Clock Tree

The input DQS clock tree is a balanced clock network that distributes the read capture clock (such as QK/QK# which are free-running read clocks) and strobe (such as DQS_T/DQS_C) from the external memory device to the read capture registers inside the I/Os.

You can configure an input DQS clock tree in x4 mode, x8 mode, or x16 mode.

Within every bank, only certain physical pins at specific locations can drive the input DQS clock trees. The pin locations that can drive the input DQS clock trees vary, depending on the size of the group.

Table 62.  Pins Usable as Read Capture Clock / Strobe Pair
Group Size Index of Lanes Spanned by Clock Tree 1 Sub-Bank Index of Pins Usable as Read Capture Clock / Strobe Pair
DQS_T DQS_C
x8 0 Bottom 4 5
x8 1 16 17
x8 2 28 29
x8 3 40 41
x8 0 Top 52 53
x8 1 64 65
x8 2 76 77
x8 3 88 89