DCMI to SD card with DMA on STM32H7

[PNare]

Greetings,

Is it possible to 'stream' camera image data from DCMI peripheral to the SD card with DMA without using any intermediate external memory? This will reduce the need for another chip.

Also would hardware JPEG encoding be possible in real time before sending the data to the SD card with DMA?

Thanks, this will help in evaluating this platform.

Cheers, Prithvi

[Tesla DeLorean]

>>Is it possible to 'stream' camera image data from DCMI peripheral to the SD card with DMA without using any intermediate external memory? This will reduce the need for another chip.

You can't pipe it directly to SD card, it has to transit through a holding buffer in memory. I can write data at 15 MBps, but depends on the card, and what else your system is doing.

You have 512KB of memory at 0x24000000, which would be more than enough to provide for multiple buffers, and queue them up for writing to the SD card.

I haven't played with the JPEG encoder, but here you're look at creating a bucket-brigade like pipeline of buffers, you want writes to the SD card to be aligned to the block size for optimum through-put, 32KB buffer likely to hit a sweet spot. I would make the software flexible so I could tune the buffer sizes.