tweaks to all steps

main/drivers/speaker.cpp

@@ -1,6 +1,6 @@
 #include "speaker.h"
 
-static i2s_chan_handle_t tx_chan;
+i2s_chan_handle_t tx_chan;
 
 static const char *TAG = "speaker_driver";
 
@@ -18,7 +18,11 @@ esp_err_t play_raw(const char *fp) {
   size_t bytes_read = 0;
   size_t bytes_written = 0;
 
-  ESP_ERROR_CHECK(i2s_channel_enable(tx_chan));
+  esp_err_t channel_enable_result = i2s_channel_enable(tx_chan);
+  ESP_ERROR_CHECK_WITHOUT_ABORT(channel_enable_result);
+  if (channel_enable_result != ESP_OK) {
+    return channel_enable_result;
+  }
 
   bytes_read = fread(read_buf, sizeof(uint8_t), AUDIO_BUFFER, fh);
   for (int i = 0; i < bytes_read; i++) {

main/drivers/speaker.h

@@ -17,6 +17,8 @@
 #define SAMPLE_RATE 44100
 #define AUDIO_BUFFER 2048
 
+extern i2s_chan_handle_t tx_chan;
+
 esp_err_t play_raw(const char *fp);
 void init_speaker(void);
 void play_example();