I am working on an STM32F401 MC for audio acquisition and I am trying to send the audio data(384 bytes exactly) from ISR to a task using queues. The frequency of the ISR is too high and hence I believe some data is dropped due to the queue being full. The audio recorded from running the code is noisy. Is there any easier way to send large amounts of data from an ISR to a task?
The RTOS used is FreeRTOS and the ISR is the DMA callback from the I2S mic peripheral.
CodePudding user response：
The general approach in these cases is:
- Down-sample the raw data received in the ISR (e.g., save only 1 out of 4 samples)
- Accumulate a certain number of samples before sending them in a message to the task
CodePudding user response：
If the thread receiving the data is called at periodic intervals, the queue should be sized sufficiently to hold all data that may be received in that interval. It would probably be a good idea to make sure the queue is large enough to hold data for at least two intervals.
If the thread receiving the data is simply unable to keep up with the incoming data, then one could consider increasing its priority.
There is some overhead processing associated with each push to and pull from the queue, since FreeRTOS will check to determine whether a higher priority task should wake up in response to the action. When writing or reading multiple items to or from the queue at the same time, it may help to suspend the scheduler while the transfer is taking place.
Another solution would be to implement a circular buffer and place it into shared memory. This will basically perform the same function as a queue, but without the extra overhead. You may need to use a mutex to block simultaneous access to the buffer, depending on how the circular buffer is implemented.