Updated API

examples/hello_pdm/main.c

@@ -13,21 +13,20 @@
 #include "tusb.h"
 
 struct pdm_microphone_config config = {
+    .gpio_clk = 2,
+    .gpio_data = 3,
     .pio = pio0,
     .pio_sm = 0,
     .sample_rate = 8000,
-    .gpio_clk = 2,
-    .gpio_data = 3,
+    .sample_buffer_size = 256,
 };
 
 int16_t sample_buffer[256];
 volatile int samples_read = 0;
 
-void on_pdm_data(int16_t* samples, uint num_samples)
+void on_pdm_samples_ready()
 {
-    memcpy(sample_buffer, samples, num_samples * sizeof(samples[0]));
-
-    samples_read = num_samples;
+  samples_read = pdm_microphone_read(sample_buffer, 256);
 }
 
 int main( void )
@@ -38,21 +37,31 @@ int main( void )
         tight_loop_contents();
     }
 
-    // printf("hello PDM microphone\n");
-
-    pdm_microphone_init(&config);
-    pdm_microphone_start(on_pdm_data);
+    printf("hello PDM microphone\n");
 
-    while (1) {
-        while (samples_read == 0) {
+    if (pdm_microphone_init(&config) < 0) {
+        printf("PDM microphone initialization failed!\n");
+        while (1) {
             tight_loop_contents();
         }
+    }
 
-        for (int i = 0; i < samples_read; i++) {
-            printf("%d\n", sample_buffer[i]);
+    pdm_microphone_set_samples_ready_handler(on_pdm_samples_ready);
+
+    if (pdm_microphone_start() < 0) {
+        printf("PDM microphone start failed!\n");
+        while (1) {
+            tight_loop_contents();
         }
+    }
 
+    while (1) {
+        int sample_count = samples_read;
         samples_read = 0;
+
+        for (int i = 0; i < sample_count; i++) {
+            printf("%d\n", sample_buffer[i]);
+        }
     }
 
     return 0;

examples/usb_microphone/main.c

@@ -67,19 +67,19 @@ void led_blinking_task(void);
 void audio_task(void);
 
 struct pdm_microphone_config config = {
-    .pio = pio0,
-    .pio_sm = 0,
-    .sample_rate = 16000,
-    .gpio_clk = 2,
-    .gpio_data = 3,
+  .gpio_clk = 2,
+  .gpio_data = 3,
+  .pio = pio0,
+  .pio_sm = 0,
+  .sample_rate = 16000,
+  .sample_buffer_size = CFG_TUD_AUDIO_TX_FIFO_SIZE/2,
 };
 
-void on_pdm_data(int16_t* samples, uint num_samples)
+void on_pdm_samples_ready()
 {
-  memcpy(test_buffer_audio, samples, num_samples * sizeof(samples[0]));
+  pdm_microphone_read(test_buffer_audio, CFG_TUD_AUDIO_TX_FIFO_SIZE/2);
 }
 
-
 /*------------- MAIN -------------*/
 int main(void)
 {
@@ -97,7 +97,8 @@ int main(void)
   sampleFreqRng.subrange[0].bRes = 0;
 
   pdm_microphone_init(&config);
-  pdm_microphone_start(on_pdm_data);
+  pdm_microphone_set_samples_ready_handler(on_pdm_samples_ready);
+  pdm_microphone_start();
 
   while (1)
   {

src/include/pico/microphone/pdm.h

@@ -10,18 +10,28 @@
 
 #include "hardware/pio.h"
 
-typedef void (*pdm_data_handler_t)(int16_t*, uint);
+typedef void (*pdm_samples_ready_handler_t)(void);
 
 struct pdm_microphone_config {
+    uint gpio_clk;
+    uint gpio_data;
     PIO pio;
     uint pio_sm;
     uint sample_rate;
-    uint gpio_clk;
-    uint gpio_data;
-    // TODO: pass in buffer???
+    uint sample_buffer_size;
 };
 
 int pdm_microphone_init(const struct pdm_microphone_config* config);
-int pdm_microphone_start(pdm_data_handler_t handler);
+void pdm_microphone_deinit();
+
+int pdm_microphone_start();
+void pdm_microphone_stop();
+
+void pdm_microphone_set_samples_ready_handler(pdm_samples_ready_handler_t handler);
+void pdm_microphone_set_filter_max_volume(uint8_t max_volume);
+void pdm_microphone_set_filter_gain(uint8_t gain);
+void pdm_microphone_set_filter_volume(uint16_t volume);
+
+int pdm_microphone_read(int16_t* buffer, size_t samples);
 
 #endif