Question: What are the changes required when the DMA channel buffer size is changed in the UVC example project of AN75779?
Make the two additional changes in the firmware to accommodate the new DMA buffer size:
- Change the LD_DATA_COUNT and LD_ADDR_COUNT values according to this equation:
Count = ((producer_buffer_size)/(data_bus_width))-1
producer_buffer_size = DMA_buf_size – header – footer
All values are in bytes.
- In the firmware, in the uvc.c file, change the last member of the glProbeCtrl and glProbeCtrl20 arrays to equal the buffer size from the default value of 16k.