STM32 I2S

Author: pschatzmann

src/AudioI2S/I2SConfigStd.h

@@ -17,12 +17,7 @@ namespace audio_tools {
 class I2SConfigStd : public AudioInfo {
   public:
 
-    I2SConfigStd() {
-      channels = DEFAULT_CHANNELS;
-      sample_rate = DEFAULT_SAMPLE_RATE; 
-      bits_per_sample = DEFAULT_BITS_PER_SAMPLE;
-    }
-
+    I2SConfigStd() = default;
     /// Default Copy Constructor
     I2SConfigStd(const I2SConfigStd &cfg) = default;
 
@@ -32,6 +27,8 @@ class I2SConfigStd : public AudioInfo {
         sample_rate = DEFAULT_SAMPLE_RATE; 
         bits_per_sample = DEFAULT_BITS_PER_SAMPLE;
         rx_tx_mode = mode;
+
+#ifndef STM32
         switch(mode){
           case RX_MODE:
             pin_data = PIN_I2S_DATA_IN;
@@ -44,21 +41,23 @@ class I2SConfigStd : public AudioInfo {
             pin_data_rx = PIN_I2S_DATA_IN;
             break;
         }
+#endif
     }
 
     /// public settings
     RxTxMode rx_tx_mode = TX_MODE;
     bool is_master = true;
-    //int port_no = 0;  // processor dependent port
+    I2SFormat i2s_format = I2S_STD_FORMAT;
+    int buffer_count = I2S_BUFFER_COUNT;
+    int buffer_size = I2S_BUFFER_SIZE;
+
+#ifndef STM32
     int pin_ws = PIN_I2S_WS;
     int pin_bck = PIN_I2S_BCK;
     int pin_data; // rx or tx pin dependent on mode: tx pin for RXTX_MODE
     int pin_data_rx; // rx pin for RXTX_MODE
     int pin_mck = PIN_I2S_MCK;
-    I2SFormat i2s_format = I2S_STD_FORMAT;
-
-    int buffer_count = I2S_BUFFER_COUNT;
-    int buffer_size = I2S_BUFFER_SIZE;
+#endif
 
 #if defined(RP2040_HOWER)
     /// materclock multiplier for RP2040: must be multiple of 64
@@ -81,6 +80,8 @@ class I2SConfigStd : public AudioInfo {
       LOGI("i2s_format: %s", i2s_formats[i2s_format]);      
       LOGI("buffer_count:%d",buffer_count);
       LOGI("buffer_size:%d",buffer_size);
+
+#ifndef STM32
       if (pin_mck!=-1)
         LOGI("pin_mck: %d", pin_mck);
       if (pin_bck!=-1)
@@ -92,6 +93,7 @@ class I2SConfigStd : public AudioInfo {
       if (pin_data_rx!=-1 && rx_tx_mode==RXTX_MODE){
         LOGI("pin_data_rx: %d", pin_data_rx);
       }
+#endif
     }
 
 };

src/AudioI2S/I2SSTM32.h

@@ -68,14 +68,14 @@ class I2SDriverSTM32 {
   /// we assume the data is already available in the buffer
   int available() {
     if (!active) return 0;
-    if (use_dma) return p_rx_buffer == nullptr ? 0 : cfg.buffer_size;
+    if (use_dma && p_rx_buffer == nullptr) return 0;
     return cfg.buffer_size;
   }
 
   /// We limit the write size to the buffer size
   int availableForWrite() {
     if (!active) return 0;
-    if (use_dma) return p_tx_buffer == nullptr ? 0 : cfg.buffer_size;
+    if (use_dma && p_tx_buffer == nullptr) return 0;
     return cfg.buffer_size;
   }
 
@@ -150,22 +150,15 @@ class I2SDriverSTM32 {
     } else {
       // get data from buffer
       if (self->stm32_write_active) {
-        // if we risk an onderflow we force the execution of the loop
-        if (self->p_tx_buffer->available() < byteCount) {
-          loop();
-        }
         read = self->p_tx_buffer->readArray(buffer, byteCount);
-      } else {
-        // force execution of loop to fill buffer;
-        loop();
-      }
+      } 
     }
 
     // check for underflow
-    count++;
-    if (read != byteCount) {
-      LOGW("Buffer undeflow at %lu: %d for %d", count, read, byteCount);
-    }
+    // count++;
+    // if (read != byteCount) {
+    //   LOGW("Buffer undeflow at %lu: %d for %d", count, read, byteCount);
+    // }
   }
 
   /// Checks if timout has been activated and if so, if it is timed out
@@ -196,7 +189,7 @@ class I2SDriverSTM32 {
   bool result = true;
   BaseBuffer<uint8_t> *p_tx_buffer = nullptr;
   BaseBuffer<uint8_t> *p_rx_buffer = nullptr;
-  bool stm32_write_active = false;
+  volatile bool stm32_write_active = false;
   bool use_dma = true;
   Print *p_dma_out = nullptr;
   Stream *p_dma_in = nullptr;
@@ -211,7 +204,8 @@ class I2SDriverSTM32 {
       result += actual_written;
       open -= actual_written;
       if (open > 0) {
-        delay(10);
+        stm32_write_active = true;
+        delay(1);
       }
     }
 
@@ -220,6 +214,7 @@ class I2SDriverSTM32 {
       stm32_write_active = true;
       LOGI("Buffer is full->starting i2s output");
     }
+
     return size_bytes;
   }
 
@@ -259,31 +254,28 @@ class I2SDriverSTM32 {
     switch (cfg.rx_tx_mode) {
       case RX_MODE:
         if (use_dma && p_rx_buffer == nullptr)
-          p_rx_buffer = new NBuffer<uint8_t>(cfg.buffer_size, cfg.buffer_count);
+          p_rx_buffer = allocateBuffer();
         result = i2s.beginReadDMA(i2s_stm32, writeFromReceive);
         break;
       case TX_MODE:
         stm32_write_active = false;
         if (use_dma && p_tx_buffer == nullptr)
-          p_tx_buffer = new NBuffer<uint8_t>(cfg.buffer_size, cfg.buffer_count);
+          p_tx_buffer = allocateBuffer();
         result = i2s.beginWriteDMA(i2s_stm32, readToTransmit);
         break;
 
-#ifdef IS_READWRITE
       case RXTX_MODE:
         if (use_dma) {
           stm32_write_active = false;
           if (p_rx_buffer == nullptr)
-            p_rx_buffer =
-                new NBuffer<uint8_t>(cfg.buffer_size, cfg.buffer_count);
+            p_rx_buffer = allocateBuffer();
           if (p_tx_buffer == nullptr)
-            p_tx_buffer =
-                new NBuffer<uint8_t>(cfg.buffer_size, cfg.buffer_count);
+            p_tx_buffer = allocateBuffer();
         }
         result = i2s.beginReadWriteDMA(
             i2s_stm32, readToTransmit, writeFromReceive);
         break;
-#endif
+
       default:
         LOGE("Unsupported mode");
         return false;
@@ -319,11 +311,9 @@ class I2SDriverSTM32 {
     i2s_stm32.data_format = toDataFormat(cfg.bits_per_sample);
     i2s_stm32.mode = getMode(cfg);
     i2s_stm32.standard = getStandard(cfg);
-#ifdef I2S_FULLDUPLEXMODE_ENABLE
     i2s_stm32.fullduplexmode = cfg.rx_tx_mode == RXTX_MODE
                                    ? I2S_FULLDUPLEXMODE_ENABLE
                                    : I2S_FULLDUPLEXMODE_DISABLE;
-#endif
     i2s_stm32.hardware_config.buffer_size = cfg.buffer_size;
     // provide ourself as parameter to callback
     i2s_stm32.ref = this;
@@ -412,6 +402,10 @@ class I2SDriverSTM32 {
     LOGD("writeBytesExt: %u", result)
     return result;
   }
+
+  BaseBuffer<uint8_t>* allocateBuffer() {
+      return new RingBuffer<uint8_t>(cfg.buffer_size * cfg.buffer_count);
+  }
 };
 
 using I2SDriver = I2SDriverSTM32;

src/AudioTools/AudioSPDIF.h

@@ -165,9 +165,11 @@ class SPDIFOutput : public AudioStream {
     I2SConfig i2s_cfg;
     i2s_cfg.sample_rate = sample_rate;
     i2s_cfg.channels = cfg.channels;
+#ifndef STM32
     i2s_cfg.pin_ws = -1;
     i2s_cfg.pin_bck = -1;
     i2s_cfg.pin_data = cfg.pin_data;
+#endif
     i2s_cfg.buffer_count = cfg.buffer_count;
     i2s_cfg.buffer_size = cfg.buffer_size;
     i2s_cfg.bits_per_sample = I2S_BITS_PER_SAMPLE;