Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorSGDMA data transfer question.
Hi,
I did a memory transfer test from RAM to SDRAM using SGDMA, the speed test was evaluated using performance counter core, and it shows the transfer rate goes up to 370 MB/s with all content copied correctly, which is too good to be true! when i used the same code on RAM to SRAM, the transfer rate only goes up to 50MB/s !!! WHY? i thought SRAM should be faster than SDRAM? i was testing my code in DE2-115. Maybe the SRAM is slower than SDRAM in DE2-115 ?? PS: Both cases were running at 100MHz.(same clock speed with CPU) Rregards, Michael13 Replies
Altera_ForumThis kind of speed is possible with SDRAM if you are using bursts or consecutive accesses, which is usually the case when transferring from a DMA.
If you had random transfers, then asynchronous SRAM could become faster than SDRAM in some cases.- Altera_Forum
How about my SDRAM speed? is this even possible at 370MB/s ?? its probably having the same transfer rate as the RAM to RAM .
- Altera_Forum
If that's asynchronous SRAM (i.e. not SSRAM) then you will not be able to read/write to the SRAM every clock cycle. Look at the SRAM datasheet timing to see what I mean.
