[WiP] Support for I2S microphones like SPH0645 (fixes #70)

examples/I2SInputEchoTest/I2SInputEchoTest.ino

@@ -0,0 +1,39 @@
+#include <Arduino.h>
+
+#ifdef ESP32
+    #include <WiFi.h>
+#else
+    #include <ESP8266WiFi.h>
+#endif
+
+#include "AudioInputI2S.h"
+#include "AudioOutputI2S.h"
+#include "AudioOutputBuffer.h"
+
+AudioInputI2S *in;
+AudioOutputI2S *out;
+AudioOutputBuffer *outbuf;
+
+void setup()
+{
+  WiFi.mode(WIFI_OFF);
+  Serial.begin(115200);
+  out = new AudioOutputI2S(0);
+  in = new AudioInputI2S(1);
+  out->SetPinout(26, 25, 22);
+  in->SetPinout(23, 18, 5);
+  //out->SetGain(0.02);
+  //in->SetGain(0.1);
+
+  outbuf = new AudioOutputBuffer(0.7*44100, out);
+  in->begin(NULL, outbuf);
+  Serial.printf("starting\n");
+}
+
+void loop()
+{
+  if (in->isRunning()) {
+    if (!in->loop()) in->stop();
+  }
+  delay(5);
+}

keywords.txt

@@ -25,3 +25,4 @@ AudioOutputSerialWAV	KEYWORD1
 AudioOutputSPIFFSWAV	KEYWORD1
 AudioOutputMixer	KEYWORD1
 AudioOutputMixerStub	KEYWORD1
+AudioInputI2S	KEYWORD1

src/AudioInputI2S.cpp

@@ -0,0 +1,215 @@
+/*
+  AudioInputI2S
+  I2S audio source
+
+*/
+
+#include <Arduino.h>
+#ifdef ESP32
+  #include "driver/i2s.h"
+#else
+  #include <i2s.h>
+#endif
+#include "AudioInputI2S.h"
+
+AudioInputI2S::AudioInputI2S(int port, int dma_buf_count, int use_apll)
+{
+  this->portNo = port;
+  this->running = false;
+  this->hertz = 44100;
+
+  buffLen = dma_buf_count*64;
+  buff = (uint8_t*)malloc(buffLen);
+
+#ifdef ESP32
+  if (!running) {
+    if (use_apll == APLL_AUTO) {
+      // don't use audio pll on buggy rev0 chips
+      use_apll = APLL_DISABLE;
+      esp_chip_info_t out_info;
+      esp_chip_info(&out_info);
+      if(out_info.revision > 0) {
+        use_apll = APLL_ENABLE;
+      }
+    }
+
+    i2s_config_t i2s_config_adc = {
+      .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX),
+      .sample_rate = hertz,
+      .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
+      .channel_format = I2S_CHANNEL_FMT_ONLY_RIGHT,
+      .communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S),
+      .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1, // high interrupt priority
+      .dma_buf_count = dma_buf_count,
+      .dma_buf_len = 64,
+      .use_apll = use_apll // Use audio PLL
+    };
+    Serial.printf("+%d %p\n", portNo, &i2s_config_adc);
+    if (i2s_driver_install((i2s_port_t)portNo, &i2s_config_adc, 0, NULL) != ESP_OK) {
+      Serial.println("ERROR: Unable to install I2S drives\n");
+    }
+    //SetPinout(21, 25, 19); // be careful not to overwrite the other i2s channel
+
+    i2s_zero_dma_buffer((i2s_port_t)portNo);
+  } 
+#else
+  (void) use_apll;
+  if (!running) {
+    i2s_begin();
+  }
+#endif
+  running = true;
+  bps = 32;
+  channels = 1;
+  gain_shift = 0;
+}
+
+AudioInputI2S::~AudioInputI2S()
+{
+#ifdef ESP32
+  if (running) {
+    Serial.printf("UNINSTALL I2S\n");
+    i2s_driver_uninstall((i2s_port_t)portNo); //stop & destroy i2s driver
+  }
+#else
+  if (running) i2s_end();
+#endif
+running = false;
+free(buff);
+}
+
+uint32_t AudioInputI2S::GetSample()
+{
+  if (!running) return 0;
+
+  uint32_t sampleIn=0;
+#ifdef ESP32
+  i2s_pop_sample((i2s_port_t)portNo, (char*)&sampleIn, portMAX_DELAY);
+  return sampleIn>>(14+gain_shift);
+#else
+  i2s_read_sample(&lastSample[LEFTCHANNEL], &lastSample[RIGHTCHANNEL], true);
+  return (lastSample[RIGHTCHANNEL] << 16) | (lastSample[LEFTCHANNEL] & 0xffff);
+#endif
+}
+
+uint32_t AudioInputI2S::read(void* data, size_t len_bytes)
+{
+  if (!running) return 0;
+  size_t bytes_read = 0;
+  //bytes_read = i2s_read_bytes((i2s_port_t)portNo, (char*)data, (size_t)len, portMAX_DELAY);
+#ifdef ESP32
+  esp_err_t err = i2s_read((i2s_port_t)portNo, data, len_bytes, &bytes_read, 0);
+#else
+  uint16_t* data16 = reinterpret_cast<uint16_t*>(data);
+  for (int i = 0; (i < len_bytes/(2*sizeof(int16_t))) && (i2s_rx_available()) > 0; i++) {
+    i2s_read_sample(&lastSample[LEFTCHANNEL], &lastSample[RIGHTCHANNEL], false);
+    data16[i+RIGHTCHANNEL] = lastSample[RIGHTCHANNEL];
+    data16[i+LEFTCHANNEL] = lastSample[LEFTCHANNEL];
+  }
+#endif
+  return bytes_read;
+}
+
+bool AudioInputI2S::SetPinout(int bclk, int wclk, int din)
+{
+#ifdef ESP32
+  i2s_pin_config_t pin_config = {
+    .bck_io_num = bclk,
+    .ws_io_num = wclk,
+    .data_out_num = I2S_PIN_NO_CHANGE,
+    .data_in_num = din
+  };
+  i2s_set_pin((i2s_port_t)portNo, &pin_config);
+  return true;
+#else
+  (void) bclk;
+  (void) wclk;
+  (void) din;
+  return false;
+#endif
+}
+
+bool AudioInputI2S::SetRate(int hz)
+{
+  // TODO - have a list of allowable rates from constructor, check them
+  this->hertz = hz;
+#ifdef ESP32
+  i2s_set_sample_rates((i2s_port_t)portNo, hz); 
+#else
+  i2s_set_rate(hz);
+#endif
+  return true;
+}
+
+bool AudioInputI2S::SetBitsPerSample(int bits)
+{
+  if ( (bits != 32) && (bits != 16) && (bits != 8) ) return false;
+  this->bps = bits;
+  return true;
+}
+
+bool AudioInputI2S::SetGain(float f)
+{
+  if (f < 0.33) this->gain_shift = 2;
+  else if (f < 0.66) this->gain_shift = 1;
+  else this->gain_shift = 0;
+  return true;
+}
+
+bool AudioInputI2S::stop() {
+  running = false;
+  output->stop();
+#ifdef ESP32
+  esp_err_t err = i2s_stop((i2s_port_t)portNo);
+  return (err == ESP_OK);
+#else
+  i2s_rxtx_begin(false, false);
+  return true;
+#endif
+}
+
+bool AudioInputI2S::isRunning() {
+  return running;
+}
+
+bool AudioInputI2S::loop() {
+  if (!running) return false;
+
+  uint32_t* buff32 = reinterpret_cast<uint32_t*>(buff);
+
+  while (validSamples) {
+    int32_t sample = buff32[curSample]>>(14+gain_shift);
+    lastSample[0] = sample;
+    lastSample[1] = sample;
+    if (!output->ConsumeSample(lastSample)) {
+      output->loop();
+      yield();
+      return true;
+    }
+    validSamples--;
+    curSample++;
+  }
+
+  validSamples = read(buff, buffLen) / sizeof(uint32_t);
+  curSample = 0;
+
+  output->loop();
+}
+
+bool AudioInputI2S::begin(AudioFileSource *source, AudioOutput *output) {
+  if (!output) return false;
+  if (!running) {
+#ifdef ESP32
+    esp_err_t err = i2s_start((i2s_port_t)portNo);
+    if (err != ESP_OK) return false;
+#else
+    i2s_rxtx_begin(true, false);
+#endif
+    running = true;
+  }
+  this->output = output;
+  output->begin();
+  output->SetBitsPerSample(bps);
+  output->SetRate(hertz);
+  return true;
+}

src/AudioInputI2S.h

@@ -0,0 +1,45 @@
+/*
+  AudioInputI2S
+  I2S audio source
+
+*/
+
+#ifndef _AUDIOINPUTI2S_H
+#define _AUDIOINPUTI2S_H
+
+#include <Arduino.h>
+#include "AudioGenerator.h"
+
+class AudioInputI2S : public AudioGenerator
+{
+  public:
+    AudioInputI2S(int port=0, int dma_buf_count = 8, int use_apll=APLL_DISABLE);
+    virtual ~AudioInputI2S() override;
+    bool SetPinout(int bclkPin, int wclkPin, int dinPin);
+    virtual bool begin(AudioFileSource *source, AudioOutput *output) override;
+    virtual bool loop() override;
+    virtual bool stop() override;
+    virtual bool isRunning() override;
+    virtual bool SetRate(int hz);
+    virtual bool SetBitsPerSample(int bits);
+    virtual bool SetGain(float f);
+    uint32_t GetSample(void);
+    virtual uint32_t read(void* data, size_t len_bytes);
+
+    enum : int { LEFTCHANNEL=0, RIGHTCHANNEL=1 };
+    enum : int { APLL_AUTO = -1, APLL_ENABLE = 1, APLL_DISABLE = 0 };
+  private:
+  protected:
+    uint8_t portNo;
+    uint16_t hertz;
+    uint8_t bps;
+    uint8_t channels;
+    AudioOutput *output;
+    int16_t buffLen;
+    uint8_t *buff;
+    int16_t validSamples;
+    int16_t curSample;
+    int gain_shift;
+};
+
+#endif // _AUDIOINPUTI2S_H