From 52a9be72381b884cfe27b7fd76c690c37dedadf9 Mon Sep 17 00:00:00 2001
From: Phil Schatzmann <phil.schatzmann@gmail.com>
Date: Fri, 10 Mar 2023 15:09:02 +0100
Subject: [PATCH 01/10] Feature esp32 input (#1)

* DRAFT read

* ESP32 Input Corrections

* Mode In Correctioins

* Remove intrernal ADC

* Final Cleanup
---
 AudioConfigESP32.h       |  55 +++++++++++--
 AudioOutput.h            |   4 +
 MozziGuts.cpp            |   2 +-
 MozziGuts_impl_ESP32.hpp | 173 +++++++++++++++++++++++++++------------
 mozzi_config.h           |   8 ++
 5 files changed, 183 insertions(+), 59 deletions(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index fd3fcba76..0c8d1ca15 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -1,6 +1,9 @@
 #ifndef AUDIOCONFIGESP32_H
 #define AUDIOCONFIGESP32_H
 
+#include <driver/i2s.h>
+#include <soc/adc_channel.h>
+
 #if not IS_ESP32()
 #error This header should be included for ESP32 architecture, only
 #endif
@@ -9,27 +12,42 @@
 #error HIFI mode is not available for this CPU architecture (but check ESP32_AUDIO_OUT_MODE, and PDM_RESOLUTION)
 #endif
 
-// Audio output options
+// Audio IO options
 #define INTERNAL_DAC 1 // output using internal DAC via I2S, output on pin 26
-#define PT8211_DAC 2 // output using an external PT8211 DAC via I2S
-#define PDM_VIA_I2S 3 // output PDM coded sample on the I2S data pin (pin 33, by default, configurable, below)
+#define PT8211_DAC 2   // OBSOLETE: use PT8211_DAC instead
+#define PDM_VIA_I2S 3  // output PDM coded sample on the I2S data pin (pin 33, by default, configurable, below)
+#define I2S_DAC_AND_I2S_ADC 4  // output using an external DAC , input with exteran ADC - both via I2S
 
-// Set output mode
+// Set output & input mode
 #define ESP32_AUDIO_OUT_MODE INTERNAL_DAC
 
 // For external I2S output, only: I2S_PINS
 #define ESP32_I2S_BCK_PIN 26
 #define ESP32_I2S_WS_PIN 25
 #define ESP32_I2S_DATA_PIN 33
+#define ESP32_I2S_DATA_PIN_IN 32  // relevant with I2S_ADC
 
-#include <driver/i2s.h>
+
+// Preferred I2S port: note that this might be taken into consideration if there is a choice
+// The Internal ADC and DAC only work on port 0 and can not be used at the same time!
 const i2s_port_t i2s_num = I2S_NUM_0;
+
+
+// Select the data range of the ADC
+//#define ADC_VALUE(in) (in) // no scaling
+#define ADC_VALUE(in) ((in + 32768)*0.015625) // scale to 0 to 1023
+
+// Optionally select a higher Sample Rate
+//#define ESP32_AUDIO_RATE 8000
+
+
 /// User config end. Do not modify below this line
+///--------------------------------------------------------------------------------------------------------
 
-#if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
+#if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC || ESP32_AUDIO_OUT_MODE == INTERNAL_DAC_AND_I2S_ADC )
 #define AUDIO_BITS 8
 #define PDM_RESOLUTION 1
-#elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC)
+#elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC || ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_INTERNAL_ADC || ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_I2S_ADC)
 #define AUDIO_BITS 16
 #define PDM_RESOLUTION 1
 #elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
@@ -39,7 +57,30 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 #error Invalid output mode configured in AudioConfigESP32.h
 #endif
 
+/// Activate Analog Input
+#if (ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_INTERNAL_ADC || ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_I2S_ADC || ESP32_AUDIO_OUT_MODE == INTERNAL_DAC_AND_I2S_ADC)
+#  define MOZZI_FAST_ANALOG_IMPLEMENTED // not yet
+#endif
+
+/// Logic for Output Buffer
+#define IS_INTERNAL_DAC() (ESP32_AUDIO_OUT_MODE==INTERNAL_DAC || ESP32_AUDIO_OUT_MODE==INTERNAL_DAC_AND_I2S_ADC)
+#define IS_I2S_DAC() (ESP32_AUDIO_OUT_MODE==I2S_DAC || ESP32_AUDIO_OUT_MODE==I2S_DAC_AND_INTERNAL_ADC||ESP32_AUDIO_OUT_MODE==I2S_DAC_AND_I2S_ADC)
+#define IS_PDM() (ESP32_AUDIO_OUT_MODE==PDM_VIA_I2S) 
+
 #define AUDIO_BIAS ((uint16_t) 1<<(AUDIO_BITS-1))
 #define BYPASS_MOZZI_OUTPUT_BUFFER true
 
+// Use defined rate as new AUDIO_RATE_PLATFORM_DEFAULT
+#ifdef ESP32_AUDIO_RATE
+#  undef AUDIO_RATE_PLATFORM_DEFAULT 
+#  define AUDIO_RATE_PLATFORM_DEFAULT ESP32_AUDIO_RATE
+#endif
+
+// If ADC is available we support getAudioInput()
+#if ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC
+int getAudioInput();
+#endif
+
+
+
 #endif        //  #ifndef AUDIOCONFIGESP_H
diff --git a/AudioOutput.h b/AudioOutput.h
index 8ad297844..fc2a28374 100644
--- a/AudioOutput.h
+++ b/AudioOutput.h
@@ -216,4 +216,8 @@ inline uint32_t pdmCode32(uint16_t sample) {
 #warning "Mozzi is configured to use an external void 'audioOutput(const AudioOutput f)' function. Please define one in your sketch"
 #endif
 
+#if (EXTERNAL_AUDIO_INPUT == true)
+#warning "Mozzi is configured to use an external int 'audioRead()' function. Please define one in your sketch"
+#endif
+
 #endif
diff --git a/MozziGuts.cpp b/MozziGuts.cpp
index 82077d9d3..87a82d495 100644
--- a/MozziGuts.cpp
+++ b/MozziGuts.cpp
@@ -117,7 +117,7 @@ int mozziAnalogRead(uint8_t pin) {
 #endif
 }
 
-#if (USE_AUDIO_INPUT == true)
+#if (USE_AUDIO_INPUT == true && !defined(USE_CUSTOM_AUDIO_INPUT) && !EXTERNAL_AUDIO_INPUT)
 // ring buffer for audio input
 CircularBuffer<unsigned int> input_buffer; // fixed size 256
 
diff --git a/MozziGuts_impl_ESP32.hpp b/MozziGuts_impl_ESP32.hpp
index 7657eb62c..67c54c7b7 100644
--- a/MozziGuts_impl_ESP32.hpp
+++ b/MozziGuts_impl_ESP32.hpp
@@ -9,59 +9,109 @@
  * Attribution-NonCommercial-ShareAlike 4.0 International License.
  *
  */
-
 #if !(IS_ESP32())
 #  error "Wrong implementation included for this platform"
 #endif
+#include "AudioConfigESP32.h"
+#include <driver/i2s.h>
+#include <soc/adc_channel.h>
+
+static const char module[]="Mozzi-ESP32";
+
+/// Make sure that we provide a supported port
+int getWritePort(){
+  switch (ESP32_AUDIO_OUT_MODE){
+    case INTERNAL_DAC: 
+      return 0;
+    case PDM_VIA_I2S:  
+      return 0;
+    case PT8211_DAC:     
+     return i2s_num;
+    case I2S_DAC_AND_I2S_ADC:  
+      return i2s_num;
+  }
+  ESP_LOGE(module, "%s - %s", __func__, "ESP32_AUDIO_OUT_MODE invalid");
+  return -1;
+}
+
+
+/// Determine the I2S Output Mode (and input mode if on same port)
+int getI2SModeOut(){
+  switch (ESP32_AUDIO_OUT_MODE){
+    case INTERNAL_DAC: 
+      return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN;
+    case PDM_VIA_I2S:  
+      return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_PDM;
+    case PT8211_DAC:     
+      return I2S_MODE_MASTER | I2S_MODE_TX;
+    case I2S_DAC_AND_I2S_ADC:  
+      return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_RX;
+  }
+   ESP_LOGE(module, "%s - %s", __func__, "ESP32_AUDIO_OUT_MODE invalid");
+ return -1;
+}
+
+
+// We provide a custom implementation of getAudioInput() avoiding the complex standard handling
+#define USE_CUSTOM_AUDIO_INPUT
+
+/// @brief  Reads a sample from the I2S buffer. I2S is stereo, so we combine the result to one single sample
+int getAudioInput() {
+  static const int i2s_port = getWritePort();
+  if (i2s_port==-1) return 0;
+
+  int16_t tmp[2];
+  size_t result;
+  esp_err_t rc = i2s_read((i2s_port_t)i2s_port, tmp, sizeof(tmp), &result, portMAX_DELAY);
+  return ADC_VALUE((tmp[0]+tmp[1]) / 2);
+}
+
+
+// ////// BEGIN analog input code ////////
+#define getADCReading() 0;
 
-////// BEGIN analog input code ////////
-//#define MOZZI_FAST_ANALOG_IMPLEMENTED // not yet
-#define getADCReading() 0
 #define channelNumToIndex(channel) channel
 uint8_t adcPinToChannelNum(uint8_t pin) {
   return pin;
 }
 void adcStartConversion(uint8_t channel) {
-#warning Fast analog read not implemented on this platform
+//    ESP_LOGD(module, "%s", __func__);
 }
 void startSecondADCReadOnCurrentChannel() {
-#warning Fast analog read not implemented on this platform
+//    ESP_LOGD(module, "%s", __func__);
 }
 void setupFastAnalogRead(int8_t speed) {
-#warning Fast analog read not implemented on this platform
+//    ESP_LOGD(module, "%s", __func__);
 }
 void setupMozziADC(int8_t speed) {
-#warning Fast analog read not implemented on this platform
+//   ESP_LOGD(module, "%s: %d", __func__, speed);
 }
 ////// END analog input code ////////
 
 
-
-
 //// BEGIN AUDIO OUTPUT code ///////
 #include <driver/i2s.h>   // for I2S-based output modes
 #include <driver/timer.h> // for EXTERNAL_AUDIO_OUTPUT
 
 #if (EXTERNAL_AUDIO_OUTPUT != true)
-#  include "AudioConfigESP32.h"
 // On ESP32 we cannot test wether the DMA buffer has room. Instead, we have to use a one-sample mini buffer. In each iteration we
 // _try_ to write that sample to the DMA buffer, and if successful, we can buffer the next sample. Somewhat cumbersome, but works.
 // TODO: Should ESP32 gain an implemenation of i2s_available(), we should switch to using that, instead.
 static bool _esp32_can_buffer_next = true;
-#  if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
+#  if (IS_INTERNAL_DAC())
 static uint16_t _esp32_prev_sample[2];
-#    define ESP_SAMPLE_SIZE (2*sizeof(uint16_t))
-#  elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC)
+#  elif (IS_I2S_DAC())
 static int16_t _esp32_prev_sample[2];
-#    define ESP_SAMPLE_SIZE (2*sizeof(int16_t))
-#  elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
+#  elif (IS_PDM())
 static uint32_t _esp32_prev_sample[PDM_RESOLUTION];
-#    define ESP_SAMPLE_SIZE (PDM_RESOLUTION*sizeof(uint32_t))
 #  endif
 
 inline bool esp32_tryWriteSample() {
+  static i2s_port_t port = (i2s_port_t) getWritePort();
   size_t bytes_written;
-  i2s_write(i2s_num, &_esp32_prev_sample, ESP_SAMPLE_SIZE, &bytes_written, 0);
+  int write_len = sizeof(_esp32_prev_sample);
+  i2s_write(port, &_esp32_prev_sample, write_len, &bytes_written, 0);
+  //ESP_LOGD(module, "%s port:%d, len: %d, written: %d, value: %d", __func__, port, write_len, bytes_written, _esp32_prev_sample[0]);
   return (bytes_written != 0);
 }
 
@@ -101,8 +151,54 @@ void CACHED_FUNCTION_ATTR timer0_audio_output_isr(void *) {
 }
 #endif
 
-static void startAudio() {
+
+static void startI2SAudio(i2s_port_t port, int mode){
+  ESP_LOGI(module, "%s: port=%d, mode=0x%x, rate=%d", __func__, port, mode, AUDIO_RATE * PDM_RESOLUTION);
+
+  static i2s_config_t i2s_config = {
+    .mode = (i2s_mode_t)mode,
+    .sample_rate = AUDIO_RATE * PDM_RESOLUTION,
+    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,  // only the top 8 bits will actually be used by the internal DAC, but using 8 bits straight away seems buggy
+    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,  // always use stereo output. mono seems to be buggy, and the overhead is insignifcant on the ESP32
+    .communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_STAND_I2S),  // this appears to be the correct setting for internal DAC and PT8211, but not for other dacs
+    .intr_alloc_flags = 0, // default interrupt priority
+    .dma_buf_count = 8,    // 8*128 bytes of buffer corresponds to 256 samples (2 channels, see above, 2 bytes per sample per channel)
+    .dma_buf_len = 128,
+    .use_apll = false,
+  };
+
+  // install i2s driver
+  if (i2s_driver_install(port, &i2s_config, 0, NULL)!=ESP_OK){
+    ESP_LOGE(module, "%s - %s : %d", __func__, "i2s_driver_install", port);
+  }
+
+  // Internal DAC
+  if (mode & I2S_MODE_DAC_BUILT_IN){
+    if (i2s_set_pin(port, NULL)!=ESP_OK) {
+        ESP_LOGE(module, "%s - %s", __func__, "i2s_set_pin");
+    }
+    if (i2s_set_dac_mode(I2S_DAC_CHANNEL_BOTH_EN)!=ESP_OK) {
+        ESP_LOGE(module, "%s - %s", __func__, "i2s_set_dac_mode");
+    }
+  // Regular I2S
+  } else {
+    static const i2s_pin_config_t pin_config = {
+      .bck_io_num = ESP32_I2S_BCK_PIN,
+      .ws_io_num = ESP32_I2S_WS_PIN,
+      .data_out_num = ESP32_I2S_DATA_PIN,
+      .data_in_num = ESP32_I2S_DATA_PIN_IN,
+    };
+    if (i2s_set_pin(port, &pin_config)!=ESP_OK) {
+      ESP_LOGE(module, "%s - %s", __func__, "i2s_set_pin");
+    }
+  }
+  i2s_zero_dma_buffer(port);
+}
+
+
 #if (BYPASS_MOZZI_OUTPUT_BUFFER != true)  // for external audio output, set up a timer running a audio rate
+
+static void startAudio() {
   static intr_handle_t s_timer_handle;
   const int div = 2;
   timer_config_t config = {
@@ -120,43 +216,18 @@ static void startAudio() {
   timer_enable_intr(TIMER_GROUP_0, TIMER_0);
   timer_isr_register(TIMER_GROUP_0, TIMER_0, &timer0_audio_output_isr, nullptr, 0, &s_timer_handle);
   timer_start(TIMER_GROUP_0, TIMER_0);
-
+}
 #else
-  static const i2s_config_t i2s_config = {
-#  if (ESP32_AUDIO_OUT_MODE == PT8211_DAC) || (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
-    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX),
-#  elif (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
-    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN),
-#  endif
-    .sample_rate = AUDIO_RATE * PDM_RESOLUTION,
-    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,  // only the top 8 bits will actually be used by the internal DAC, but using 8 bits straight away seems buggy
-    .channel_format = I2S_CHANNEL_FMT_RIGHT_LEFT,  // always use stereo output. mono seems to be buggy, and the overhead is insignifcant on the ESP32
-    .communication_format = (i2s_comm_format_t)(I2S_COMM_FORMAT_I2S | I2S_COMM_FORMAT_I2S_LSB),  // this appears to be the correct setting for internal DAC and PT8211, but not for other dacs
-    .intr_alloc_flags = 0, // default interrupt priority
-    .dma_buf_count = 8,    // 8*128 bytes of buffer corresponds to 256 samples (2 channels, see above, 2 bytes per sample per channel)
-    .dma_buf_len = 128,
-    .use_apll = false
-  };
 
-  i2s_driver_install(i2s_num, &i2s_config, 0, NULL);
-#  if (ESP32_AUDIO_OUT_MODE == PT8211_DAC) || (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
-  static const i2s_pin_config_t pin_config = {
-    .bck_io_num = ESP32_I2S_BCK_PIN,
-    .ws_io_num = ESP32_I2S_WS_PIN,
-    .data_out_num = ESP32_I2S_DATA_PIN,
-    .data_in_num = -1
-  };
-  i2s_set_pin((i2s_port_t)i2s_num, &pin_config);
-#  elif (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
-  i2s_set_pin((i2s_port_t)i2s_num, NULL);
-  i2s_set_dac_mode(I2S_DAC_CHANNEL_BOTH_EN);
-#  endif
-  i2s_zero_dma_buffer((i2s_port_t)i2s_num);
+/// Use I2S for the Output and Input
+static void startAudio() {
+  // start output
+  startI2SAudio((i2s_port_t)getWritePort(), getI2SModeOut());
+}
 
 #endif
-}
 
 void stopMozzi() {
-  // TODO: implement me
+  i2s_driver_uninstall((i2s_port_t)getWritePort());
 }
 //// END AUDIO OUTPUT code ///////
diff --git a/mozzi_config.h b/mozzi_config.h
index 1881e2de9..03412dbef 100644
--- a/mozzi_config.h
+++ b/mozzi_config.h
@@ -112,4 +112,12 @@ Only used when EXTERNAL_AUDIO_OUTPUT is set to true: The resolution to use for a
 output resolution of your DAC. 16 is the default value, here. Note that 16 bits is also the maximum currently supported on AVR. */
 //#define EXTERNAL_AUDIO_BITS 16
 
+/** @ingroup core
+Defining this option as true in mozzi_config.h allows to completely customize the audio input, e.g. for connecting from an external DACs.
+For more detail, @see AudioInput .
+*/
+#define EXTERNAL_AUDIO_INPUT false
+//#define EXTERNAL_AUDIO_INPUT true
+
+
 #endif        //  #ifndef MOZZI_CONFIG_H

From e523259d05da37520c11a025bcb5cbcbff9a74bc Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Fri, 10 Mar 2023 15:23:04 +0100
Subject: [PATCH 02/10] Remove EXTERNAL_AUDIO_INPUT

---
 AudioConfigESP32.h | 6 +++---
 AudioOutput.h      | 4 ----
 MozziGuts.cpp      | 2 +-
 mozzi_config.h     | 6 ------
 4 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index 0c8d1ca15..760b46210 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -44,10 +44,10 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 /// User config end. Do not modify below this line
 ///--------------------------------------------------------------------------------------------------------
 
-#if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC || ESP32_AUDIO_OUT_MODE == INTERNAL_DAC_AND_I2S_ADC )
+#if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
 #define AUDIO_BITS 8
 #define PDM_RESOLUTION 1
-#elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC || ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_INTERNAL_ADC || ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_I2S_ADC)
+#elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC  || ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC)
 #define AUDIO_BITS 16
 #define PDM_RESOLUTION 1
 #elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
@@ -58,7 +58,7 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 #endif
 
 /// Activate Analog Input
-#if (ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_INTERNAL_ADC || ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_I2S_ADC || ESP32_AUDIO_OUT_MODE == INTERNAL_DAC_AND_I2S_ADC)
+#if (ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_INTERNAL_ADC || ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC || ESP32_AUDIO_OUT_MODE == INTERNAL_DAC_AND_I2S_ADC)
 #  define MOZZI_FAST_ANALOG_IMPLEMENTED // not yet
 #endif
 
diff --git a/AudioOutput.h b/AudioOutput.h
index fc2a28374..8ad297844 100644
--- a/AudioOutput.h
+++ b/AudioOutput.h
@@ -216,8 +216,4 @@ inline uint32_t pdmCode32(uint16_t sample) {
 #warning "Mozzi is configured to use an external void 'audioOutput(const AudioOutput f)' function. Please define one in your sketch"
 #endif
 
-#if (EXTERNAL_AUDIO_INPUT == true)
-#warning "Mozzi is configured to use an external int 'audioRead()' function. Please define one in your sketch"
-#endif
-
 #endif
diff --git a/MozziGuts.cpp b/MozziGuts.cpp
index 87a82d495..adc9d357c 100644
--- a/MozziGuts.cpp
+++ b/MozziGuts.cpp
@@ -117,7 +117,7 @@ int mozziAnalogRead(uint8_t pin) {
 #endif
 }
 
-#if (USE_AUDIO_INPUT == true && !defined(USE_CUSTOM_AUDIO_INPUT) && !EXTERNAL_AUDIO_INPUT)
+#if (USE_AUDIO_INPUT == true && !defined(USE_CUSTOM_AUDIO_INPUT))
 // ring buffer for audio input
 CircularBuffer<unsigned int> input_buffer; // fixed size 256
 
diff --git a/mozzi_config.h b/mozzi_config.h
index 03412dbef..25b2ee6ba 100644
--- a/mozzi_config.h
+++ b/mozzi_config.h
@@ -112,12 +112,6 @@ Only used when EXTERNAL_AUDIO_OUTPUT is set to true: The resolution to use for a
 output resolution of your DAC. 16 is the default value, here. Note that 16 bits is also the maximum currently supported on AVR. */
 //#define EXTERNAL_AUDIO_BITS 16
 
-/** @ingroup core
-Defining this option as true in mozzi_config.h allows to completely customize the audio input, e.g. for connecting from an external DACs.
-For more detail, @see AudioInput .
-*/
-#define EXTERNAL_AUDIO_INPUT false
-//#define EXTERNAL_AUDIO_INPUT true
 
 
 #endif        //  #ifndef MOZZI_CONFIG_H

From 3816fc619521050dfab7de946dd30faf94f2ed66 Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Fri, 10 Mar 2023 15:30:55 +0100
Subject: [PATCH 03/10] README.md

---
 README.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/README.md b/README.md
index 7e495b4dc..c47815a0f 100644
--- a/README.md
+++ b/README.md
@@ -277,6 +277,9 @@ port by Dieter Vandoren and Thomas Friedrichsmeier
     - Output (DATA) pin can be configured in AudioConfigESP32.h. Default 33. Note that the BCK and WS pins are also used in this mode.
     - The PDM_RESOLUTION parameter can be used to reduce noise at the cost of more CPU power.
     - Mono, only.
+  - I2S_DAC_AND_I2S_ADC: Output is sent via I2S in a format, Input is read from I2S in douplex mode.
+    - 16 bits resolution, mono or stereo. Remember to shift your audio accordingly.
+    - I2S ins can be configured in AudioConfigESP32.h. Default is BCK: 26, WS: 15, DATA: 33, DATA_IN: 32.
 - "HIFI_MODE" is not currently implemented, but could conceivably be realized for the INTERNAL_DAC mode. Patches welcome.
 - WIFI-activity not yet tested, but likely the same notes as for ESP8266 apply. Consider turning off WIFI.
 - The implementation of audioTicks() may be slightly inaccurate on this platform.

From 785f1c1c6a6fe36b31253fe52a3dc41b7c72086c Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 08:36:58 +0100
Subject: [PATCH 04/10] ADC scaling

---
 AudioConfigESP32.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index 760b46210..67e8cde0a 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -35,7 +35,7 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 
 // Select the data range of the ADC
 //#define ADC_VALUE(in) (in) // no scaling
-#define ADC_VALUE(in) ((in + 32768)*0.015625) // scale to 0 to 1023
+#define ADC_VALUE(in) (0.015625*(in + 32768)) // scale to 0 to 1023
 
 // Optionally select a higher Sample Rate
 //#define ESP32_AUDIO_RATE 8000

From e9665bf8387a7b6d8837e7f1805378a94babf85f Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 09:12:24 +0100
Subject: [PATCH 05/10] Cleanup

---
 AudioConfigESP32.h       | 17 +++++------------
 MozziGuts_impl_ESP32.hpp | 24 ++++++++++--------------
 2 files changed, 15 insertions(+), 26 deletions(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index 67e8cde0a..118edfac6 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -14,7 +14,7 @@
 
 // Audio IO options
 #define INTERNAL_DAC 1 // output using internal DAC via I2S, output on pin 26
-#define PT8211_DAC 2   // OBSOLETE: use PT8211_DAC instead
+#define PT8211_DAC 2 // output using an external PT8211 DAC via I2S
 #define PDM_VIA_I2S 3  // output PDM coded sample on the I2S data pin (pin 33, by default, configurable, below)
 #define I2S_DAC_AND_I2S_ADC 4  // output using an external DAC , input with exteran ADC - both via I2S
 
@@ -25,7 +25,7 @@
 #define ESP32_I2S_BCK_PIN 26
 #define ESP32_I2S_WS_PIN 25
 #define ESP32_I2S_DATA_PIN 33
-#define ESP32_I2S_DATA_PIN_IN 32  // relevant with I2S_ADC
+#define ESP32_I2S_DATA_PIN_IN 32  
 
 
 // Preferred I2S port: note that this might be taken into consideration if there is a choice
@@ -47,26 +47,19 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 #if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
 #define AUDIO_BITS 8
 #define PDM_RESOLUTION 1
+#define IS_INTERNAL_DAC
 #elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC  || ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC)
 #define AUDIO_BITS 16
 #define PDM_RESOLUTION 1
+#define IS_I2S_DAC
 #elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
 #define AUDIO_BITS 16
 #define PDM_RESOLUTION 4
+#define IS_PDM
 #else
 #error Invalid output mode configured in AudioConfigESP32.h
 #endif
 
-/// Activate Analog Input
-#if (ESP32_AUDIO_OUT_MODE == PT8211_DAC_AND_INTERNAL_ADC || ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC || ESP32_AUDIO_OUT_MODE == INTERNAL_DAC_AND_I2S_ADC)
-#  define MOZZI_FAST_ANALOG_IMPLEMENTED // not yet
-#endif
-
-/// Logic for Output Buffer
-#define IS_INTERNAL_DAC() (ESP32_AUDIO_OUT_MODE==INTERNAL_DAC || ESP32_AUDIO_OUT_MODE==INTERNAL_DAC_AND_I2S_ADC)
-#define IS_I2S_DAC() (ESP32_AUDIO_OUT_MODE==I2S_DAC || ESP32_AUDIO_OUT_MODE==I2S_DAC_AND_INTERNAL_ADC||ESP32_AUDIO_OUT_MODE==I2S_DAC_AND_I2S_ADC)
-#define IS_PDM() (ESP32_AUDIO_OUT_MODE==PDM_VIA_I2S) 
-
 #define AUDIO_BIAS ((uint16_t) 1<<(AUDIO_BITS-1))
 #define BYPASS_MOZZI_OUTPUT_BUFFER true
 
diff --git a/MozziGuts_impl_ESP32.hpp b/MozziGuts_impl_ESP32.hpp
index 67c54c7b7..d70673769 100644
--- a/MozziGuts_impl_ESP32.hpp
+++ b/MozziGuts_impl_ESP32.hpp
@@ -13,8 +13,8 @@
 #  error "Wrong implementation included for this platform"
 #endif
 #include "AudioConfigESP32.h"
-#include <driver/i2s.h>
-#include <soc/adc_channel.h>
+#include <driver/i2s.h>   // for I2S-based output modes
+#include <driver/timer.h> // for EXTERNAL_AUDIO_OUTPUT
 
 static const char module[]="Mozzi-ESP32";
 
@@ -26,7 +26,7 @@ int getWritePort(){
     case PDM_VIA_I2S:  
       return 0;
     case PT8211_DAC:     
-     return i2s_num;
+      return i2s_num;
     case I2S_DAC_AND_I2S_ADC:  
       return i2s_num;
   }
@@ -36,7 +36,7 @@ int getWritePort(){
 
 
 /// Determine the I2S Output Mode (and input mode if on same port)
-int getI2SModeOut(){
+int getI2SMode(){
   switch (ESP32_AUDIO_OUT_MODE){
     case INTERNAL_DAC: 
       return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN;
@@ -89,20 +89,16 @@ void setupMozziADC(int8_t speed) {
 ////// END analog input code ////////
 
 
-//// BEGIN AUDIO OUTPUT code ///////
-#include <driver/i2s.h>   // for I2S-based output modes
-#include <driver/timer.h> // for EXTERNAL_AUDIO_OUTPUT
-
 #if (EXTERNAL_AUDIO_OUTPUT != true)
 // On ESP32 we cannot test wether the DMA buffer has room. Instead, we have to use a one-sample mini buffer. In each iteration we
 // _try_ to write that sample to the DMA buffer, and if successful, we can buffer the next sample. Somewhat cumbersome, but works.
 // TODO: Should ESP32 gain an implemenation of i2s_available(), we should switch to using that, instead.
 static bool _esp32_can_buffer_next = true;
-#  if (IS_INTERNAL_DAC())
+#  if defined(IS_INTERNAL_DAC)
 static uint16_t _esp32_prev_sample[2];
-#  elif (IS_I2S_DAC())
+#  elif defined(IS_I2S_DAC)
 static int16_t _esp32_prev_sample[2];
-#  elif (IS_PDM())
+#  elif defined(IS_PDM)
 static uint32_t _esp32_prev_sample[PDM_RESOLUTION];
 #  endif
 
@@ -122,7 +118,7 @@ inline bool canBufferAudioOutput() {
 }
 
 inline void audioOutput(const AudioOutput f) {
-#  if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
+#  if defined(IS_INTERNAL_DAC)
   _esp32_prev_sample[0] = (f.l() + AUDIO_BIAS) << 8;
 #    if (AUDIO_CHANNELS > 1)
   _esp32_prev_sample[1] = (f.r() + AUDIO_BIAS) << 8;
@@ -130,7 +126,7 @@ inline void audioOutput(const AudioOutput f) {
   // For simplicity of code, even in mono, we're writing stereo samples
   _esp32_prev_sample[1] = _esp32_prev_sample[0];
 #    endif
-#  elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
+#  elif defined(IS_PDM)
   for (uint8_t i=0; i<PDM_RESOLUTION; ++i) {
     _esp32_prev_sample[i] = pdmCode32(f.l() + AUDIO_BIAS);
   }
@@ -222,7 +218,7 @@ static void startAudio() {
 /// Use I2S for the Output and Input
 static void startAudio() {
   // start output
-  startI2SAudio((i2s_port_t)getWritePort(), getI2SModeOut());
+  startI2SAudio((i2s_port_t)getWritePort(), getI2SMode());
 }
 
 #endif

From 94ea47d8685812a4f5512591f5508b8b0fbb44fa Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 09:18:30 +0100
Subject: [PATCH 06/10] Cleanup USE_CUSTOM_AUDIO_INPUT

---
 AudioConfigESP32.h       | 3 +--
 MozziGuts_impl_ESP32.hpp | 4 ----
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index 118edfac6..08ceeab50 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -71,9 +71,8 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 
 // If ADC is available we support getAudioInput()
 #if ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC
+#  define USE_CUSTOM_AUDIO_INPUT
 int getAudioInput();
 #endif
 
-
-
 #endif        //  #ifndef AUDIOCONFIGESP_H
diff --git a/MozziGuts_impl_ESP32.hpp b/MozziGuts_impl_ESP32.hpp
index d70673769..e6509874d 100644
--- a/MozziGuts_impl_ESP32.hpp
+++ b/MozziGuts_impl_ESP32.hpp
@@ -51,10 +51,6 @@ int getI2SMode(){
  return -1;
 }
 
-
-// We provide a custom implementation of getAudioInput() avoiding the complex standard handling
-#define USE_CUSTOM_AUDIO_INPUT
-
 /// @brief  Reads a sample from the I2S buffer. I2S is stereo, so we combine the result to one single sample
 int getAudioInput() {
   static const int i2s_port = getWritePort();

From 5ad8be21ed3f46be43f56e6ebf27326f4dde8de7 Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 09:43:16 +0100
Subject: [PATCH 07/10] Cleanup mozzi_config.h

---
 mozzi_config.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mozzi_config.h b/mozzi_config.h
index 25b2ee6ba..1881e2de9 100644
--- a/mozzi_config.h
+++ b/mozzi_config.h
@@ -112,6 +112,4 @@ Only used when EXTERNAL_AUDIO_OUTPUT is set to true: The resolution to use for a
 output resolution of your DAC. 16 is the default value, here. Note that 16 bits is also the maximum currently supported on AVR. */
 //#define EXTERNAL_AUDIO_BITS 16
 
-
-
 #endif        //  #ifndef MOZZI_CONFIG_H

From 58c714f7753f64291f4b8dfc07524ece5add4a6b Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 10:05:51 +0100
Subject: [PATCH 08/10] Add original warnings for ADC

---
 MozziGuts_impl_ESP32.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/MozziGuts_impl_ESP32.hpp b/MozziGuts_impl_ESP32.hpp
index e6509874d..48fdf958e 100644
--- a/MozziGuts_impl_ESP32.hpp
+++ b/MozziGuts_impl_ESP32.hpp
@@ -71,16 +71,16 @@ uint8_t adcPinToChannelNum(uint8_t pin) {
   return pin;
 }
 void adcStartConversion(uint8_t channel) {
-//    ESP_LOGD(module, "%s", __func__);
+#warning Fast analog read not implemented on this platform
 }
 void startSecondADCReadOnCurrentChannel() {
-//    ESP_LOGD(module, "%s", __func__);
+#warning Fast analog read not implemented on this platform
 }
 void setupFastAnalogRead(int8_t speed) {
-//    ESP_LOGD(module, "%s", __func__);
+#warning Fast analog read not implemented on this platform
 }
 void setupMozziADC(int8_t speed) {
-//   ESP_LOGD(module, "%s: %d", __func__, speed);
+#warning Fast analog read not implemented on this platform
 }
 ////// END analog input code ////////
 

From 96b1110883320cd3b1d8e18cfb69d96dba14a8ba Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 10:52:23 +0100
Subject: [PATCH 09/10] Support External ouput

---
 AudioConfigESP32.h       |  3 ++-
 MozziGuts_impl_ESP32.hpp | 10 +++++-----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index 08ceeab50..8965e6310 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -41,6 +41,7 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 //#define ESP32_AUDIO_RATE 8000
 
 
+///--------------------------------------------------------------------------------------------------------
 /// User config end. Do not modify below this line
 ///--------------------------------------------------------------------------------------------------------
 
@@ -61,7 +62,7 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 #endif
 
 #define AUDIO_BIAS ((uint16_t) 1<<(AUDIO_BITS-1))
-#define BYPASS_MOZZI_OUTPUT_BUFFER true
+#define BYPASS_MOZZI_OUTPUT_BUFFER !EXTERNAL_AUDIO_OUTPUT
 
 // Use defined rate as new AUDIO_RATE_PLATFORM_DEFAULT
 #ifdef ESP32_AUDIO_RATE
diff --git a/MozziGuts_impl_ESP32.hpp b/MozziGuts_impl_ESP32.hpp
index 48fdf958e..a700996f6 100644
--- a/MozziGuts_impl_ESP32.hpp
+++ b/MozziGuts_impl_ESP32.hpp
@@ -19,7 +19,7 @@
 static const char module[]="Mozzi-ESP32";
 
 /// Make sure that we provide a supported port
-int getWritePort(){
+int getI2SPort(){
   switch (ESP32_AUDIO_OUT_MODE){
     case INTERNAL_DAC: 
       return 0;
@@ -53,7 +53,7 @@ int getI2SMode(){
 
 /// @brief  Reads a sample from the I2S buffer. I2S is stereo, so we combine the result to one single sample
 int getAudioInput() {
-  static const int i2s_port = getWritePort();
+  static const int i2s_port = getI2SPort();
   if (i2s_port==-1) return 0;
 
   int16_t tmp[2];
@@ -99,7 +99,7 @@ static uint32_t _esp32_prev_sample[PDM_RESOLUTION];
 #  endif
 
 inline bool esp32_tryWriteSample() {
-  static i2s_port_t port = (i2s_port_t) getWritePort();
+  static i2s_port_t port = (i2s_port_t) getI2SPort();
   size_t bytes_written;
   int write_len = sizeof(_esp32_prev_sample);
   i2s_write(port, &_esp32_prev_sample, write_len, &bytes_written, 0);
@@ -214,12 +214,12 @@ static void startAudio() {
 /// Use I2S for the Output and Input
 static void startAudio() {
   // start output
-  startI2SAudio((i2s_port_t)getWritePort(), getI2SMode());
+  startI2SAudio((i2s_port_t)getI2SPort(), getI2SMode());
 }
 
 #endif
 
 void stopMozzi() {
-  i2s_driver_uninstall((i2s_port_t)getWritePort());
+  i2s_driver_uninstall((i2s_port_t)getI2SPort());
 }
 //// END AUDIO OUTPUT code ///////

From c49ecaafaf4f29c966f0708c3f8a48960fe12a1b Mon Sep 17 00:00:00 2001
From: pschatzmann <phil.schatzmann@gmail.com>
Date: Sat, 11 Mar 2023 12:42:16 +0100
Subject: [PATCH 10/10] Cleanup Logic

---
 AudioConfigESP32.h       |  51 +++++++------
 MozziGuts_impl_ESP32.hpp | 161 +++++++++++++++++++++------------------
 2 files changed, 112 insertions(+), 100 deletions(-)

diff --git a/AudioConfigESP32.h b/AudioConfigESP32.h
index 8965e6310..26d19476d 100644
--- a/AudioConfigESP32.h
+++ b/AudioConfigESP32.h
@@ -44,36 +44,37 @@ const i2s_port_t i2s_num = I2S_NUM_0;
 ///--------------------------------------------------------------------------------------------------------
 /// User config end. Do not modify below this line
 ///--------------------------------------------------------------------------------------------------------
-
-#if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
-#define AUDIO_BITS 8
-#define PDM_RESOLUTION 1
-#define IS_INTERNAL_DAC
-#elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC  || ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC)
-#define AUDIO_BITS 16
-#define PDM_RESOLUTION 1
-#define IS_I2S_DAC
-#elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
-#define AUDIO_BITS 16
-#define PDM_RESOLUTION 4
-#define IS_PDM
-#else
-#error Invalid output mode configured in AudioConfigESP32.h
-#endif
-
-#define AUDIO_BIAS ((uint16_t) 1<<(AUDIO_BITS-1))
-#define BYPASS_MOZZI_OUTPUT_BUFFER !EXTERNAL_AUDIO_OUTPUT
+#if !EXTERNAL_AUDIO_OUTPUT
+#  if (ESP32_AUDIO_OUT_MODE == INTERNAL_DAC)
+#    define AUDIO_BITS 8
+#    define PDM_RESOLUTION 1
+#    define IS_INTERNAL_DAC
+#  elif (ESP32_AUDIO_OUT_MODE == PT8211_DAC  || ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC)
+#    define AUDIO_BITS 16
+#    define PDM_RESOLUTION 1
+#    define IS_I2S_DAC
+#  elif (ESP32_AUDIO_OUT_MODE == PDM_VIA_I2S)
+#    define AUDIO_BITS 16
+#    define PDM_RESOLUTION 4
+#    define IS_PDM
+#  else
+#  error Invalid output mode configured in AudioConfigESP32.h
+#  endif
+
+#  define AUDIO_BIAS ((uint16_t) 1<<(AUDIO_BITS-1))
+#  define BYPASS_MOZZI_OUTPUT_BUFFER true
 
 // Use defined rate as new AUDIO_RATE_PLATFORM_DEFAULT
-#ifdef ESP32_AUDIO_RATE
-#  undef AUDIO_RATE_PLATFORM_DEFAULT 
-#  define AUDIO_RATE_PLATFORM_DEFAULT ESP32_AUDIO_RATE
-#endif
+#  ifdef ESP32_AUDIO_RATE
+#    undef AUDIO_RATE_PLATFORM_DEFAULT 
+#    define AUDIO_RATE_PLATFORM_DEFAULT ESP32_AUDIO_RATE
+#  endif
 
 // If ADC is available we support getAudioInput()
-#if ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC
-#  define USE_CUSTOM_AUDIO_INPUT
+#  if ESP32_AUDIO_OUT_MODE == I2S_DAC_AND_I2S_ADC
+#    define USE_CUSTOM_AUDIO_INPUT
 int getAudioInput();
+#  endif
 #endif
 
 #endif        //  #ifndef AUDIOCONFIGESP_H
diff --git a/MozziGuts_impl_ESP32.hpp b/MozziGuts_impl_ESP32.hpp
index a700996f6..a5cb72efd 100644
--- a/MozziGuts_impl_ESP32.hpp
+++ b/MozziGuts_impl_ESP32.hpp
@@ -18,6 +18,78 @@
 
 static const char module[]="Mozzi-ESP32";
 
+
+// ////// BEGIN analog input code ////////
+#define getADCReading() 0;
+
+#define channelNumToIndex(channel) channel
+uint8_t adcPinToChannelNum(uint8_t pin) {
+  return pin;
+}
+void adcStartConversion(uint8_t channel) {
+#warning Fast analog read not implemented on this platform
+}
+void startSecondADCReadOnCurrentChannel() {
+#warning Fast analog read not implemented on this platform
+}
+void setupFastAnalogRead(int8_t speed) {
+#warning Fast analog read not implemented on this platform
+}
+void setupMozziADC(int8_t speed) {
+#warning Fast analog read not implemented on this platform
+}
+////// END analog input code ////////
+
+
+#if (EXTERNAL_AUDIO_OUTPUT) // for external audio output, set up a timer running a audio rate
+
+void CACHED_FUNCTION_ATTR timer0_audio_output_isr(void *) {
+  TIMERG0.int_clr_timers.t0 = 1;
+  TIMERG0.hw_timer[0].config.alarm_en = 1;
+  defaultAudioOutput();
+}
+
+
+static void startAudio() {
+  static intr_handle_t s_timer_handle;
+  const int div = 2;
+  timer_config_t config = {
+    .alarm_en = (timer_alarm_t)true,
+    .counter_en = (timer_start_t)false,
+    .intr_type = (timer_intr_mode_t) TIMER_INTR_LEVEL,
+    .counter_dir = TIMER_COUNT_UP,
+    .auto_reload = (timer_autoreload_t) true,
+    .divider = div // For max available precision: The APB_CLK clock signal is running at 80 MHz, i.e. 2/80 uS per tick
+                 // Min acceptable value is 2
+  };
+  timer_init(TIMER_GROUP_0, TIMER_0, &config);
+  timer_set_counter_value(TIMER_GROUP_0, TIMER_0, 0);
+  timer_set_alarm_value(TIMER_GROUP_0, TIMER_0, 80000000UL / AUDIO_RATE / div);
+  timer_enable_intr(TIMER_GROUP_0, TIMER_0);
+  timer_isr_register(TIMER_GROUP_0, TIMER_0, &timer0_audio_output_isr, nullptr, 0, &s_timer_handle);
+  timer_start(TIMER_GROUP_0, TIMER_0);
+}
+
+void stopMozzi() {
+  timer_pause(TIMER_GROUP_0, TIMER_0);
+  timer_disable_intr(TIMER_GROUP_0, TIMER_0);
+}
+
+#else // I2S Output
+
+// On ESP32 we cannot test wether the DMA buffer has room. Instead, we have to use a one-sample mini buffer. In each iteration we
+// _try_ to write that sample to the DMA buffer, and if successful, we can buffer the next sample. Somewhat cumbersome, but works.
+// TODO: Should ESP32 gain an implemenation of i2s_available(), we should switch to using that, instead.
+static bool _esp32_can_buffer_next = true;
+#  if defined(IS_INTERNAL_DAC)
+static uint16_t _esp32_prev_sample[2];
+#  elif defined(IS_I2S_DAC)
+static int16_t _esp32_prev_sample[2];
+#  elif defined(IS_PDM)
+static uint32_t _esp32_prev_sample[PDM_RESOLUTION];
+#  endif
+
+
 /// Make sure that we provide a supported port
 int getI2SPort(){
   switch (ESP32_AUDIO_OUT_MODE){
@@ -39,15 +111,19 @@ int getI2SPort(){
 int getI2SMode(){
   switch (ESP32_AUDIO_OUT_MODE){
     case INTERNAL_DAC: 
+      ESP_LOGD(module, "%s: %s", __func__, "I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN");
       return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_DAC_BUILT_IN;
     case PDM_VIA_I2S:  
+      ESP_LOGD(module, "%s: %s", __func__, "I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_PDM");
       return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_PDM;
     case PT8211_DAC:     
+      ESP_LOGD(module, "%s: %s", __func__, "I2S_MODE_MASTER | I2S_MODE_TX");
       return I2S_MODE_MASTER | I2S_MODE_TX;
     case I2S_DAC_AND_I2S_ADC:  
+      ESP_LOGD(module, "%s: %s", __func__, "I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_RX");
       return I2S_MODE_MASTER | I2S_MODE_TX | I2S_MODE_RX;
   }
-   ESP_LOGE(module, "%s - %s", __func__, "ESP32_AUDIO_OUT_MODE invalid");
+   ESP_LOGE(module, "%s: %s", __func__, "ESP32_AUDIO_OUT_MODE invalid");
  return -1;
 }
 
@@ -63,41 +139,6 @@ int getAudioInput() {
 }
 
 
-// ////// BEGIN analog input code ////////
-#define getADCReading() 0;
-
-#define channelNumToIndex(channel) channel
-uint8_t adcPinToChannelNum(uint8_t pin) {
-  return pin;
-}
-void adcStartConversion(uint8_t channel) {
-#warning Fast analog read not implemented on this platform
-}
-void startSecondADCReadOnCurrentChannel() {
-#warning Fast analog read not implemented on this platform
-}
-void setupFastAnalogRead(int8_t speed) {
-#warning Fast analog read not implemented on this platform
-}
-void setupMozziADC(int8_t speed) {
-#warning Fast analog read not implemented on this platform
-}
-////// END analog input code ////////
-
-
-#if (EXTERNAL_AUDIO_OUTPUT != true)
-// On ESP32 we cannot test wether the DMA buffer has room. Instead, we have to use a one-sample mini buffer. In each iteration we
-// _try_ to write that sample to the DMA buffer, and if successful, we can buffer the next sample. Somewhat cumbersome, but works.
-// TODO: Should ESP32 gain an implemenation of i2s_available(), we should switch to using that, instead.
-static bool _esp32_can_buffer_next = true;
-#  if defined(IS_INTERNAL_DAC)
-static uint16_t _esp32_prev_sample[2];
-#  elif defined(IS_I2S_DAC)
-static int16_t _esp32_prev_sample[2];
-#  elif defined(IS_PDM)
-static uint32_t _esp32_prev_sample[PDM_RESOLUTION];
-#  endif
-
 inline bool esp32_tryWriteSample() {
   static i2s_port_t port = (i2s_port_t) getI2SPort();
   size_t bytes_written;
@@ -133,16 +174,6 @@ inline void audioOutput(const AudioOutput f) {
 #  endif
   _esp32_can_buffer_next = esp32_tryWriteSample();
 }
-#endif
-
-#if (BYPASS_MOZZI_OUTPUT_BUFFER != true)
-void CACHED_FUNCTION_ATTR timer0_audio_output_isr(void *) {
-  TIMERG0.int_clr_timers.t0 = 1;
-  TIMERG0.hw_timer[0].config.alarm_en = 1;
-  defaultAudioOutput();
-}
-#endif
-
 
 static void startI2SAudio(i2s_port_t port, int mode){
   ESP_LOGI(module, "%s: port=%d, mode=0x%x, rate=%d", __func__, port, mode, AUDIO_RATE * PDM_RESOLUTION);
@@ -165,7 +196,7 @@ static void startI2SAudio(i2s_port_t port, int mode){
   }
 
   // Internal DAC
-  if (mode & I2S_MODE_DAC_BUILT_IN){
+  if (ESP32_AUDIO_OUT_MODE==INTERNAL_DAC){
     if (i2s_set_pin(port, NULL)!=ESP_OK) {
         ESP_LOGE(module, "%s - %s", __func__, "i2s_set_pin");
     }
@@ -187,39 +218,19 @@ static void startI2SAudio(i2s_port_t port, int mode){
   i2s_zero_dma_buffer(port);
 }
 
-
-#if (BYPASS_MOZZI_OUTPUT_BUFFER != true)  // for external audio output, set up a timer running a audio rate
-
-static void startAudio() {
-  static intr_handle_t s_timer_handle;
-  const int div = 2;
-  timer_config_t config = {
-    .alarm_en = (timer_alarm_t)true,
-    .counter_en = (timer_start_t)false,
-    .intr_type = (timer_intr_mode_t) TIMER_INTR_LEVEL,
-    .counter_dir = TIMER_COUNT_UP,
-    .auto_reload = (timer_autoreload_t) true,
-    .divider = div // For max available precision: The APB_CLK clock signal is running at 80 MHz, i.e. 2/80 uS per tick
-                 // Min acceptable value is 2
-  };
-  timer_init(TIMER_GROUP_0, TIMER_0, &config);
-  timer_set_counter_value(TIMER_GROUP_0, TIMER_0, 0);
-  timer_set_alarm_value(TIMER_GROUP_0, TIMER_0, 80000000UL / AUDIO_RATE / div);
-  timer_enable_intr(TIMER_GROUP_0, TIMER_0);
-  timer_isr_register(TIMER_GROUP_0, TIMER_0, &timer0_audio_output_isr, nullptr, 0, &s_timer_handle);
-  timer_start(TIMER_GROUP_0, TIMER_0);
-}
-#else
-
 /// Use I2S for the Output and Input
 static void startAudio() {
   // start output
-  startI2SAudio((i2s_port_t)getI2SPort(), getI2SMode());
+  i2s_port_t port = (i2s_port_t)getI2SPort();
+  startI2SAudio(port, getI2SMode());
 }
 
-#endif
-
 void stopMozzi() {
-  i2s_driver_uninstall((i2s_port_t)getI2SPort());
+  i2s_port_t port = (i2s_port_t)getI2SPort();
+  i2s_stop(port);
+  i2s_driver_uninstall(port);
 }
+
+#endif
+
 //// END AUDIO OUTPUT code ///////