djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

certain odd-sized PDMIn record buffers would crash or not fill properly

Browse Source
This commit is contained in:
Dan Halbert 2017-12-23 00:15:16 -05:00 committed by Scott Shawcroft
parent 2d2735c9d4
commit 7918714043
1 changed files with 14 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
atmel-samd/common-hal/audiobusio/PDMIn.c
View File

@ -213,11 +213,15 @@ static void setup_dma(audiobusio_pdmin_obj_t* self, uint32_t length,
}
dma_descriptor_create(audio_dma.descriptor, &descriptor_config);
// Do we need more values than will fit in the first buffer?
// If so, set up a second buffer chained to be filled after the first buffer.
if (length * words_per_sample > words_per_buffer) {
block_transfer_count = words_per_buffer;
descriptor_config.next_descriptor_address = ((uint32_t)audio_dma.descriptor);
if (length * words_per_sample < 2 * words_per_buffer) {
block_transfer_count = 2 * words_per_buffer - length * words_per_sample;
// Length needed is more than one buffer but less than two.
// Subtract off the size of the first buffer, and what remains is the count we need.
block_transfer_count = length * words_per_sample - words_per_buffer;
descriptor_config.next_descriptor_address = 0;
}
descriptor_config.block_transfer_count = block_transfer_count;
@ -309,18 +313,21 @@ uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t* se
uint32_t remaining_samples_needed = output_buffer_length;
while (values_output < output_buffer_length) {
// Wait for the next buffer to fill
while (tc_get_count_value(MP_STATE_VM(audiodma_block_counter)) == buffers_processed) {
uint32_t block_counter;
while ((block_counter = tc_get_count_value(MP_STATE_VM(audiodma_block_counter))) == buffers_processed) {
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
if (tc_get_count_value(MP_STATE_VM(audiodma_block_counter)) != (buffers_processed + 1)) {
if (block_counter != (buffers_processed + 1)) {
// Looks like we aren't keeping up. We shouldn't skip a buffer.
break;
}
// The mic is running all the time, so we don't need to wait the usual 10msec or 100msec
// for it to start up.
// Flip back and forth between processing the first and second buffers.
uint32_t *buffer = first_buffer;
DmacDescriptor* descriptor = audio_dma.descriptor;
if (buffers_processed % 2 == 1) {
@ -342,15 +349,13 @@ uint32_t common_hal_audiobusio_pdmin_record_to_buffer(audiobusio_pdmin_obj_t* se
}
values_output++;
}
buffers_processed++;
// See if we need to transfer less than a full buffer for the remaining needed samples.
// We might need fewer than an entire of samples, but we won't try to alter the
// last DMA, which might already be in progress, so we'll just throw away some
// samples at the end.
remaining_samples_needed = output_buffer_length - values_output;
if (remaining_samples_needed > 0 && remaining_samples_needed < samples_per_buffer) {
descriptor->BTCNT.reg = remaining_samples_needed;
descriptor->DSTADDR.reg = ((uint32_t) buffer) + remaining_samples_needed * words_per_sample;
descriptor->DESCADDR.reg = 0;
}
}
stop_dma(self);