dma for image processing

[johnmalkovich]

Posted on June 01, 2009 at 03:09

dma for image processing

[johnmalkovich]

Posted on May 17, 2011 at 13:13

Hello.

I have camera sensor with 8 bit parallel video output. Average frequency is 30 MHz. Is it possible to store a frame to external SRAM using processor's DMA? The same question is about external FLASH.

[johnmalkovich]

Posted on May 17, 2011 at 13:13

Quote:

No DMA on GPIO.

That is the answer. I read in datasheet about TIM channel of DMA and thought that there is a way of DMA on GPIO.

Quote:

Better for external H/W to write the external RAM then hand it off to your STM32.

Yes, I asked about DMA to avoid using external hardware. It seems that will use FIFO-like memory or emulate it with some hard logic.

Quote:

You have asked about I/O bandwidtn. You also need interal compute crunch processing power as well.

No processing during DMA is expected. After data is loaded into RAM I'm going to just switch off camera and start slow processing (JPEG encoding) with STM32, using the same RAM.

[picguy]

Posted on May 17, 2011 at 13:13

No DMA on GPIO. Perhaps the FSMC might be fast enough. But you are pushing the limit hard. 16 bits @15MHz would work better. H/W should be simple.

Oh wait, you want external static RAM. Better for external H/W to write the external RAM then hand it off to your STM32. Dual port RAM would help but a simple handoff would save on h/w cost. Streaming at that rate would be pushing current STM32's to the wall. How much internal processing will you need? You have asked about I/O bandwidtn. You also need interal compute crunch processing power as well.