Does STM32H750 support mem2mem DMA (ChatGPT said it doesn't)?

[yah1003]

Hi Dear friends,

I am trying to configure H750 to transfer data between internal SRAM and external SDRAM, I got everything setup OK but with some problems (also monitor data bus with logic analyzer). So I checked with ChatGPT, surprisingly, ChatGPT said H750 (actually it said the same thing about H74x)  does not officially support memory-to-memory transfer, ChatGPR said use MDMA instead. Before I jump into MDMA, just want to make sure what ChatGPT said is true?

Thanks.

[TDK]

What does the Reference Manual say?

[Pavel A.]

Hi,

For H750 please see the bus matrix picture in RM0433

The full story is a bit complicated. Chatgpt can elaborate more.

[yah1003]

Hi,

Reference Manual does not say any thing about this (at least not that I could find), it just gives a general description not specifically for SDRAM<->SRAM 

[yah1003]

Yes, I already checked the reference manual for the DMA, but don't know what I should look for, I've spent a whole day trying it on real hardware and it seems DMA between SDRAM and SRAM works, but that is just for very limited test I've done! Could you elaborate more?

[mƎALLEm · Accepted solution]

Hello,

From the reference manual / table 3:

So you can do transfers from/to SRAM1/SRAM2/SRAM3 <-> FMC. you cannot do that transfer to from DTCM/ITCM. You need MDMA for that.

BDMA could not do that kind of transfer.

[Pavel A.]

Please see RM0433: bus matrix Figure 1 (pg. 105) and 22.5.  Your external SDRAM likely is connected thru the FMC.

Look for information about DMA controllers that can connect FMC and other memories.