Hello,
I'm slowly losing my sanity so I figure I'd make a post here. I set up SAI4 to interface with BDMA, hoping to retrieve data from the onboard MEMS microphone and store it in a buffer in RAM_D3. Ideally I'd like for that data to be processed by the CPU, but I can't even get the buffer to fill up.
The following code produces the output below:
audio_buffer[0] = 5;
audio_buffer[1] = 6;
audio_buffer[2] = 7;
audio_buffer[3] = 8;
// ...
// Inside main loop:
printf("SAI State: %d \r\n", HAL_SAI_GetState(&hsai_BlockA4));
printf("SAI Error: %lu \r\n", HAL_SAI_GetError(&hsai_BlockA4));
printf("SAI Buffer Address: 0x%08lx\r\n", SAI4_Block_A->DR);
printf("DMA State: %d \r\n", HAL_DMA_GetState(&hdma_sai4_a));
printf("DMA Error: %lu \r\n", HAL_DMA_GetError(&hdma_sai4_a));
printf("Pointer location: %p \r\n", audio_buffer);
printf("Audio Buffer Data:\r\n");
for (int i = 0; i < 10; i++) {
printf("[%d]: %d\r\n", i, audio_buffer[i]);
}
As you can see, SAI4 is in HAL_SAI_STATE_BUSY_RX and BDMA is in HAL_DMA_STATE_BUSY. However, audio_buffer is not being filled. It's worth mentioning that there doesn't even seem to be zeroes coming into the buffer, as the values I set manually are never changed.
Does anyone know what may be causing this? I'll drop my CubeMX configuration, in case it is useful:
Thanks in advance :(
I found a way to mux ~32.768 MHz (i.e. 16,000 * 2048) to the SAI4. With master clock division and oversampling disabled, I still get all zeroes. This is 16 bits per sample. If I probe the clock pin, I see 128kHz, which doesn't feel right either.
Thank you for the reply, I'll keep chipping away at this. The clock is a new lead. I'm just so lost on how to configure it properly (it looks like a lot of registers and formulas)
