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

DMårt
Lead

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

STM32MP151AAC3 custom board with STM32-OS as operating system: https://github.com/DanielMartensson/STM32-Computer
1 ACCEPTED SOLUTION

Accepted Solutions

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?

0693W00000NpnaqQAB.png 

JW

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3 REPLIES 3
Sara BEN HADJ YAHYA
ST Employee

Hello @Daniel Mårtensson​ ,

Thanks for your feedback,

The only DMA request available for DCMI is DCMI_PSSI.

0693W00000NpiFYQAZ.pngAfter 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:

If your issue is solved, please close this post by clicking the "Select as Best" button. This will help other members of the community find this response more quickly :)

Sara.

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?

STM32MP151AAC3 custom board with STM32-OS as operating system: https://github.com/DanielMartensson/STM32-Computer

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?

0693W00000NpnaqQAB.png 

JW