External Memory Interface Handbook Volume 2: Design Guidelines

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ID 683385
Date 5/08/2017
Public
Document Table of Contents

1.4.2.2. Rules to Combine Groups

For devices that do not have four ×16/×18 groups in a single side of the device to form two ×36 groups for read and write data, you can form one ×36 group on one side of the device, and another ×36 group on the other side of the device. All the read groups have to be on the same edge (column I/O or row I/O) and all write groups have to be on the same type of edge (column I/O or row I/O), so you can have an interface with the read group in column I/O and the write group in row I/O. The only restriction is that you cannot combine an ×18 group from column I/O with an ×18 group from row IO to form a x36-emulated group.

For vertical migration with the ×36 emulation implementation, check if migration is possible and enable device migration in the Quartus Prime software.

Note: I/O bank 1C in both Stratix III and Stratix IV devices has dual-function configuration pins. Some of the DQS pins may not be available for memory interfaces if these are used for device configuration purposes.

Each side of the device in these packages has four remaining ×8/×9 groups. You can combine four of the remaining for the write side (only) if you want to keep the ×36 QDR II and QDR II+ SRAM interface on one side of the device, by changing the Memory Interface Data Group default assignment, from the default 18 to 9.

For more information about rules to combine groups for your target device, refer to the External Memory Interfaces chapter in the respective device handbooks.

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