AN 829: PCI Express* Avalon® -MM DMA Reference Design

ID 683554
Date 6/11/2018

1.3.3. Throughput Differences for On-Chip and External Memory

This reference design provides a choice between on-chip memory implemented in the FPGA fabric and external memory available on the PCB. The on-chip memory supports separate read and write ports. Consequently, this memory supports simultaneous read and the write DMAs.

The external memory supports a single port. Consequently, the external memory does not support simultaneous read DMA and write DMA accesses. In addition, the latency of external memory is higher than the latency of on-chip memory. These two differences between the on-chip and external memory result in lower throughput for the external memory implementation.

To compare the throughput for on-chip and external memory, select command 7 for consecutive runs to switch between on-chip and external memory.

Did you find the information on this page useful?

Characters remaining:

Feedback Message