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Graduate II
July 10, 2024
Question

STM32H750VBT6 DCMI USART

  • July 10, 2024
  • 3 replies
  • 1775 views

With DCMI (with DMA) and USART only 1.5FPS, why is the frame rate really low?

The output is set to QVGA and formatted as JPEG.

Shiina_0-1720607635646.png

Shiina_1-1720607659868.png

Shiina_2-1720607674883.png

 

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    3 replies

    Graduate II
    July 10, 2024

    Probably because the bandwidth of.the UART is very low?

    ShiinaAuthor
    Graduate II
    July 10, 2024

    I set the baudrate to 912600, and the camera output is JPEG, so I don't think USART is too slow.

    Graduate II
    July 10, 2024

    Depends on image size and efficiency. Frame rate suggests images about 60KB

    Technical Moderator
    July 10, 2024

    Hello @Shiina ,

    Which camera sensor are you using? Are you encountering the same behavior with RGB? 

    Please take a look at How to improve DCMI frame rate: An example using a ov5640 camera module may help you to increase the DCMI frame rate.

    Thank you.

    Kaouthar

    ShiinaAuthor
    Graduate II
    July 11, 2024

    Thanks, I'm using ov2640, which outputs the jpeg directly.

    Technical Moderator
    July 11, 2024

    Hello @Shiina ,

     

    I advise you to take a look at JPEG data capture section in AN5020 may help you to check the DCMI configuration.

    Do you have the same issue with a different mode and image size?

     

    Thank you.

    Kaouthar

    ShiinaAuthor
    Graduate II
    July 11, 2024

    Thank you. I haven't tested anything else yet.