What DMA settings should I use for DCMI for STM32 if I'm using OV7670 camera without FIFO?

[DMårt]

What DMA settings should I use for DCMI for STM32 if I'm using OV7670 camera without FIFO?

[Sara BEN HADJ YAHYA]

Hello @Daniel Mårtensson​ ,

Thanks for your feedback,

The only DMA request available for DCMI is DCMI_PSSI.

After selecting it in CubeMX, The following three lines will be generated in HAL_DCMI_MspInit() function.

A specific comment is added to inform that only one LINK will be useful.

* Several peripheral DMA handle pointers point to the same DMA handle. Be aware that there is only one channel to perform all the requested DMAs. */
 __HAL_LINKDMA(hpssi,DMA_Handle,hdma_dcmi_pssi);
 __HAL_LINKDMA(hpssi,hdmarx,hdma_dcmi_pssi);
 __HAL_LINKDMA(hpssi,hdmatx,hdma_dcmi_pssi);

__HAL_LINKDMA(hpssi,DMA_Handle,hdma_dcmi_pssi) request should be kept and the others should be commented.

Please make sure to comment the unneeded lines each time you re-generate the code.

I hope this helps :smiling_face_with_smiling_eyes:

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Sara.

[DMårt]

Hello @Sara BEN HADJ YAHYA​ 

Yes. But how about the rest of the settings such as FIFO settings, memory? Should it be Word, or Half word?

[waclawek.jan]

Which STM32?

> FIFO settings,

You mean DMA FIFO? Yes, make the best use of it, this is a high-bandwidth peripheral.

> memory

RAM.

> Should it be Word, or Half word?

 

JW