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PDM: Unload pio program when end method is called #315

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Merged
merged 2 commits into from
Sep 13, 2021
Merged

PDM: Unload pio program when end method is called #315

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c996ed7
Set decimation and rawBufferIndex to their default value
pennam Sep 2, 2021
2913b42
Add pio_remove_program function to PDM end method
pennam Sep 2, 2021
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Add pio_remove_program function to PDM end method
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@pennam
pennam committed Sep 2, 2021
commit 2913b4248355aa527d035b05079555b90ab265b7
14 changes: 12 additions & 2 deletions libraries/PDM/src/rp2040/PDM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,9 @@ uint dmaChannel = 0;
PIO pio = pio0;
uint sm = 0;

// PIO program offset
static uint offset;

// raw buffers contain PDM data
#define RAW_BUFFER_SIZE 512 // should be a multiple of (decimation / 8)
uint8_t rawBuffer0[RAW_BUFFER_SIZE];
Expand Down Expand Up @@ -103,8 +106,13 @@ int PDMClass::begin(int channels, int sampleRate)

// Configure PIO state machine
float clkDiv = (float)clock_get_hz(clk_sys) / sampleRate / decimation / 2;
uint offset = pio_add_program(pio, &pdm_pio_program);
pdm_pio_program_init(pio, sm, offset, _clkPin, _dinPin, clkDiv);
if(pio_can_add_program(pio, &pdm_pio_program)) {
offset = pio_add_program(pio, &pdm_pio_program);
pdm_pio_program_init(pio, sm, offset, _clkPin, _dinPin, clkDiv);
} else {
mbed_error_printf("Cannot load pio program\n");
mbed_die();
}

// Wait for microphone
delay(100);
Expand Down Expand Up @@ -137,10 +145,12 @@ int PDMClass::begin(int channels, int sampleRate)

void PDMClass::end()
{
pio_remove_program(pio, &pdm_pio_program, offset);
dma_channel_abort(dmaChannel);
pinMode(_clkPin, INPUT);
decimation = 128;
rawBufferIndex = 0;
offset = 0;
}

int PDMClass::available()
Expand Down