T-Echo Card audio support initial stages - codec2 attempts

2026-08-04 15:52:42 +02:00 · 2026-05-07 05:47:18 +10:00
parent 4b734f1bac
commit 708b96e0e8
109 changed files with 87144 additions and 24 deletions
@@ -0,0 +1,261 @@
+/*
+  PDM.cpp - library to interface with nRF52840 PDM peripheral
+  Part of Arduino - http://www.arduino.cc/
+
+  Copyright (c) 2019 Arduino SA
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General
+  Public License along with this library; if not, write to the
+  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+  Boston, MA  02111-1307  USA
+*/
+
+#include "PDM.h"
+#include <hal/nrf_pdm.h>
+
+#include <Adafruit_TinyUSB.h> // for Serial
+
+#define DEFAULT_PDM_GAIN     20
+#define PDM_IRQ_PRIORITY     7
+
+#define NRF_PDM_FREQ_1280K  (nrf_pdm_freq_t)(0x0A000000UL)               ///< PDM_CLK= 1.280 MHz (32 MHz / 25) => Fs= 20000 Hz
+#define NRF_PDM_FREQ_2000K  (nrf_pdm_freq_t)(0x10000000UL)               ///< PDM_CLK= 2.000 MHz (32 MHz / 16) => Fs= 31250 Hz
+#define NRF_PDM_FREQ_2667K  (nrf_pdm_freq_t)(0x15000000UL)               ///< PDM_CLK= 2.667 MHz (32 MHz / 12) => Fs= 41667 Hz
+#define NRF_PDM_FREQ_3200K  (nrf_pdm_freq_t)(0x19000000UL)               ///< PDM_CLK= 3.200 MHz (32 MHz / 10) => Fs= 50000 Hz
+#define NRF_PDM_FREQ_4000K  (nrf_pdm_freq_t)(0x20000000UL)               ///< PDM_CLK= 4.000 MHz (32 MHz /  8) => Fs= 62500 Hz
+
+PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
+  _dinPin(dinPin),
+  _clkPin(clkPin),
+  _pwrPin(pwrPin),
+  _onReceive(NULL)
+{
+}
+
+PDMClass::~PDMClass()
+{
+}
+
+void PDMClass::setPins(int dataPin, int clkPin, int pwrPin)
+{
+  _dinPin = dataPin;
+  _clkPin = clkPin;
+  _pwrPin = pwrPin;
+}
+
+int PDMClass::begin(int channels, long sampleRate)
+{
+  _channels = channels;
+
+  // Enable high frequency oscillator if not already enabled
+  uint8_t sd_en = 0;
+  sd_softdevice_is_enabled(&sd_en);
+
+  if (sd_en)
+  {
+    uint32_t is_running;
+    sd_clock_hfclk_is_running(&is_running);
+
+    if (!is_running) {
+      sd_clock_hfclk_request();
+
+      while(!is_running) {
+        yield();
+        sd_clock_hfclk_is_running(&is_running);
+      }
+    }
+  }
+  else
+  {
+    if (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) {
+      NRF_CLOCK->TASKS_HFCLKSTART    = 1;
+      while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) yield();
+    }
+  }
+
+  // configure the sample rate and channels
+  switch (sampleRate) {
+    case 16000:
+      #ifndef NRF52832_XXAA
+      NRF_PDM->RATIO = ((PDM_RATIO_RATIO_Ratio80 << PDM_RATIO_RATIO_Pos) & PDM_RATIO_RATIO_Msk);
+      #endif
+      nrf_pdm_clock_set(NRF_PDM, NRF_PDM_FREQ_1280K);
+      break;
+    case 41667:
+      nrf_pdm_clock_set(NRF_PDM, NRF_PDM_FREQ_2667K);
+      break;
+    default:
+      return 0; // unsupported
+  }
+
+  switch (channels) {
+    case 2:
+      nrf_pdm_mode_set(NRF_PDM, NRF_PDM_MODE_STEREO, NRF_PDM_EDGE_LEFTFALLING);
+      break;
+
+    case 1:
+      nrf_pdm_mode_set(NRF_PDM, NRF_PDM_MODE_MONO, NRF_PDM_EDGE_LEFTFALLING);
+      break;
+
+    default:
+      return 0; // unsupported
+  }
+
+  setGain(DEFAULT_PDM_GAIN);  
+
+  // configure the I/O and mux
+  pinMode(_clkPin, OUTPUT);
+  digitalWrite(_clkPin, LOW);
+
+  pinMode(_dinPin, INPUT);
+
+  nrf_pdm_psel_connect(NRF_PDM, digitalPinToPinName(_clkPin), digitalPinToPinName(_dinPin));
+
+  // clear events and enable PDM interrupts
+  nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_STARTED);
+  nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_END);
+  nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_STOPPED);
+  nrf_pdm_int_enable(NRF_PDM, NRF_PDM_INT_STARTED | NRF_PDM_INT_STOPPED);
+
+  if (_pwrPin > -1) {
+    // power the mic on
+    pinMode(_pwrPin, OUTPUT);
+    digitalWrite(_pwrPin, HIGH);
+  }
+
+  // clear the buffer
+  _doubleBuffer.reset();
+
+  // set the PDM IRQ priority and enable
+  NVIC_SetPriority(PDM_IRQn, PDM_IRQ_PRIORITY);
+  NVIC_ClearPendingIRQ(PDM_IRQn);
+  NVIC_EnableIRQ(PDM_IRQn);
+
+  // set the buffer for transfer
+  // nrf_pdm_buffer_set((uint32_t*)_doubleBuffer.data(), _doubleBuffer.availableForWrite() / (sizeof(int16_t) * _channels));
+  // _doubleBuffer.swap();
+  
+  // enable and trigger start task
+  nrf_pdm_enable(NRF_PDM);
+  nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_STARTED);
+  nrf_pdm_task_trigger(NRF_PDM, NRF_PDM_TASK_START);
+
+  return 1;
+}
+
+void PDMClass::end()
+{
+  // disable PDM and IRQ
+  nrf_pdm_disable(NRF_PDM);
+
+  NVIC_DisableIRQ(PDM_IRQn);
+
+  if (_pwrPin > -1) {
+    // power the mic off
+    digitalWrite(_pwrPin, LOW);
+    pinMode(_pwrPin, INPUT);
+  }
+
+  // Don't disable high frequency oscillator since it could be in use by RADIO
+
+  // unconfigure the I/O and un-mux
+  nrf_pdm_psel_disconnect(NRF_PDM);
+
+  pinMode(_clkPin, INPUT);
+}
+
+int PDMClass::available()
+{
+  NVIC_DisableIRQ(PDM_IRQn);
+
+  size_t avail = _doubleBuffer.available();
+
+  NVIC_EnableIRQ(PDM_IRQn);
+
+  return avail;
+}
+
+int PDMClass::read(void* buffer, size_t size)
+{
+  NVIC_DisableIRQ(PDM_IRQn);
+
+  int read = _doubleBuffer.read(buffer, size);
+
+  NVIC_EnableIRQ(PDM_IRQn);
+
+  return read;
+}
+
+void PDMClass::onReceive(void(*function)(void))
+{
+  _onReceive = function;
+}
+
+void PDMClass::setGain(int gain)
+{
+  nrf_pdm_gain_set(NRF_PDM, gain, gain);
+}
+
+void PDMClass::setBufferSize(int bufferSize)
+{
+  _doubleBuffer.setSize(bufferSize);
+}
+
+void PDMClass::IrqHandler()
+{
+  if (nrf_pdm_event_check(NRF_PDM, NRF_PDM_EVENT_STARTED)) {
+    nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_STARTED);
+
+    if (_doubleBuffer.available() == 0) {
+      // switch to the next buffer
+      nrf_pdm_buffer_set(NRF_PDM, (uint32_t*)_doubleBuffer.data(), _doubleBuffer.availableForWrite() / (sizeof(int16_t) * _channels));
+
+      // make the current one available for reading
+      _doubleBuffer.swap(_doubleBuffer.availableForWrite());
+
+      // call receive callback if provided
+      if (_onReceive) {
+        _onReceive();
+      }
+    } else {
+      // buffer overflow, stop
+      nrf_pdm_disable(NRF_PDM);
+    }
+  } else if (nrf_pdm_event_check(NRF_PDM, NRF_PDM_EVENT_STOPPED)) {
+    nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_STOPPED);
+  } else if (nrf_pdm_event_check(NRF_PDM, NRF_PDM_EVENT_END)) {
+    nrf_pdm_event_clear(NRF_PDM, NRF_PDM_EVENT_END);
+  }
+}
+
+extern "C"
+{
+  void PDM_IRQHandler(void)
+  {
+    PDM.IrqHandler();
+  }
+}
+
+#ifndef PIN_PDM_DIN
+#define PIN_PDM_DIN -1
+#endif
+
+#ifndef PIN_PDM_CLK
+#define PIN_PDM_CLK -1
+#endif
+
+#ifndef PIN_PDM_PWR
+#define PIN_PDM_PWR -1
+#endif
+
+PDMClass PDM(PIN_PDM_DIN, PIN_PDM_CLK, PIN_PDM_PWR);