Hello everyone!
I'm developing a firmware to capture video frame from a thermal camera.I was using a F4 chip.But due to the resolution and fps , I had to migrate to H7 (STM32H745).And now I'm having strage problems with the dcmi.
The dcmi start sucessfully and capture every frame but sorpresively the buffer start and finish with zeros, the rest is ok .Strangely the first 12 bytes and the lastes 20 bytes. Even if I put the D0 directly to the 3.3V !.In this case the rest of data is resposive and I can see that the DCMI is capturing well D0 .
In the begining I thought that was a VSYNC , problem but that makes no sense if I'm always putting the data 0 in high and still getting zeros :(.
Thanks in advance !
Following is more information:
Camera Info:
- data is valid on high state of vsync and hsync
- data must be captured on rising edge of pxclk
- camera resolution is 80x80 , 6400 pixels => 12800 bytes
- camera sends the data in a port of 8bits D0-D7
- 1 pixel (14 bits) is composed by two contiguous capturing of two bytes (MSB first )
- PXCLK frequency is 745Khz by now , then I pretend to use 12Mhz
BSP Configuration:
... Clock enable
... GPIO configuration
hdma_handler.Init.Request = DMA_REQUEST_DCMI;
hdma_handler.Init.Direction = DMA_PERIPH_TO_MEMORY;
hdma_handler.Init.PeriphInc = DMA_PINC_DISABLE;
hdma_handler.Init.MemInc = DMA_MINC_ENABLE;
hdma_handler.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
hdma_handler.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;
hdma_handler.Init.Mode = DMA_NORMAL;
hdma_handler.Init.Priority = DMA_PRIORITY_HIGH;
hdma_handler.Init.FIFOMode = DMA_FIFOMODE_ENABLE;
hdma_handler.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL;
hdma_handler.Init.MemBurst = DMA_MBURST_SINGLE;
hdma_handler.Init.PeriphBurst = DMA_PBURST_SINGLE;
hdma_handler.Instance = DMA2_Stream3;
DCMI Init:
hdcmi.Instance = DCMI;
hdcmi.Init.SynchroMode = DCMI_SYNCHRO_HARDWARE;
hdcmi.Init.PCKPolarity = DCMI_PCKPOLARITY_FALLING;
hdcmi.Init.VSPolarity = DCMI_VSPOLARITY_LOW;
hdcmi.Init.HSPolarity = DCMI_HSPOLARITY_LOW;
hdcmi.Init.CaptureRate = DCMI_CR_ALL_FRAME;
hdcmi.Init.ExtendedDataMode = DCMI_EXTEND_DATA_8B;
hdcmi.Init.JPEGMode = DCMI_JPEG_DISABLE;
hdcmi.Init.ByteSelectMode = DCMI_BSM_ALL;
hdcmi.Init.ByteSelectStart = DCMI_OEBS_ODD;
hdcmi.Init.LineSelectMode = DCMI_LSM_ALL;
hdcmi.Init.LineSelectStart = DCMI_OELS_ODD;
And finally to start the capturing :
HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_CONTINUOUS,
(uint32_t) &frame_byte_buffer[0], (uint32_t) 3200)
I used 3200 ,suposing that the transferring is four by four byte
