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AR# 41706 MIG 7 Series - Can FPGA banks be shared among memory interfaces?

Is it possible to share an FPGA bank between two MIG interfaces? In other words, if a bank containing one memory interface contains unused T* byte groups, can these unused byte groups be assigned to a different memory controller?

No, FPGA banks cannot be shared between multiple memory controllers.

DDR3 SDRAM Bank Sharing

For DDR3 SDRAM, each interface requires a unique PHY Control Block in all interface banks. The PHY Control Block is dedicated logic that controls the FIFOs and Phasers within the bank. Both Address/Control and Data Byte Groups use the PHY Control Block within the bank and only one PHY Control Block exists in an FPGA bank. Therefore, it is not possible to share a bank between two DDR3 SDRAM interfaces. This is documented in the Design Guidelines section of the 7 Series FPGAs Memory Interface Solutions User Guide (UG586).
http://www.xilinx.com/support/documentation/ip_documentation/ug586_7Series_MIS.pdf

QDRII+/RLDRAMII Bank Sharing

While QDRII+/RLDRAMII only use the PHY Control Block on the outbound (write) path, Xilinx currently only supports unique FPGA banks for all memory interfaces in 7 series. If this were supported, it would have to be for interfaces operating at the same frequency. Xilinx is currently determining the feasibility of a bank sharing solution. If it is found to be feasible, a schedule for development would need to be set. Until this is complete, anything outside of a unique bank placement for each controller cannot be recommended.

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
51317 Xilinx MIG Solution Center, MIG 7 Series Design Assistant - Verify pin-out/banking requirements are met N/A N/A
51676 MIG 7 Series Solution DDR2/DDR3 - Supported Features N/A N/A
AR# 41706
Date Created 08/16/2012
Last Updated 02/26/2013
Status Active
Type General Article
Devices
  • Kintex-7
  • Virtex-7
IP
  • MIG
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