Clear I2C status on short slave reads

Fixes #222

The HW needs to have the TXC_ABRT flag cleared when a slave transmission is
cut short by the master, or else it will effectively break the I2C bus and
never recover.

cores/rp2040/SerialUART.cpp

@@ -161,7 +161,7 @@ void SerialUART::flush() {
     if (!_running || !m) {
         return;
     }
-    uart_default_tx_wait_blocking();
+    uart_tx_wait_blocking(_uart);
 }
 
 size_t SerialUART::write(uint8_t c) {

libraries/PDM/examples/PDMSerialPlotter/PDMSerialPlotter.ino

@@ -0,0 +1,83 @@
+/*
+  This example reads audio data from the on-board PDM microphones, and prints
+  out the samples to the Serial console. The Serial Plotter built into the
+  Arduino IDE can be used to plot the audio data (Tools -> Serial Plotter)
+
+  Circuit:
+  - Arduino Nano 33 BLE board, or
+  - Arduino Nano RP2040 Connect, or
+  - Arduino Portenta H7 board plus Portenta Vision Shield
+
+  This example code is in the public domain.
+*/
+
+#include <PDM.h>
+
+// default number of output channels
+static const char channels = 1;
+
+// default PCM output frequency
+static const int frequency = 16000;
+
+// Buffer to read samples into, each sample is 16-bits
+short sampleBuffer[512];
+
+// Number of audio samples read
+volatile int samplesRead;
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial);
+
+  // Configure the data receive callback
+  PDM.onReceive(onPDMdata);
+
+  // Optionally set the gain
+  // Defaults to 20 on the BLE Sense and -10 on the Portenta Vision Shield
+  // PDM.setGain(30);
+
+  // Initialize PDM with:
+  // - one channel (mono mode)
+  // - a 16 kHz sample rate for the Arduino Nano 33 BLE Sense
+  // - a 32 kHz or 64 kHz sample rate for the Arduino Portenta Vision Shield
+  if (!PDM.begin(channels, frequency)) {
+    Serial.println("Failed to start PDM!");
+    while (1);
+  }
+}
+
+void loop() {
+  // Wait for samples to be read
+  if (samplesRead) {
+
+    // Print samples to the serial monitor or plotter
+    for (int i = 0; i < samplesRead; i++) {
+      if(channels == 2) {
+        Serial.print("L:");
+        Serial.print(sampleBuffer[i]);
+        Serial.print(" R:");
+        i++;
+      }
+      Serial.println(sampleBuffer[i]);
+    }
+
+    // Clear the read count
+    samplesRead = 0;
+  }
+}
+
+/**
+ * Callback function to process the data from the PDM microphone.
+ * NOTE: This callback is executed as part of an ISR.
+ * Therefore using `Serial` to print messages inside this function isn't supported.
+ * */
+void onPDMdata() {
+  // Query the number of available bytes
+  int bytesAvailable = PDM.available();
+
+  // Read into the sample buffer
+  PDM.read(sampleBuffer, bytesAvailable);
+
+  // 16-bit, 2 bytes per sample
+  samplesRead = bytesAvailable / 2;
+}

libraries/PDM/keywords.txt

@@ -0,0 +1,27 @@
+#######################################
+# Syntax Coloring Map PDM
+#######################################
+
+#######################################
+# Datatypes (KEYWORD1)
+#######################################
+
+PDM	KEYWORD1
+
+#######################################
+# Methods and Functions (KEYWORD2)
+#######################################
+begin	KEYWORD2
+end	KEYWORD2
+
+available	KEYWORD2
+read	KEYWORD2
+
+onReceive	KEYWORD2
+
+setGain	KEYWORD2
+setBufferSize	KEYWORD2
+
+#######################################
+# Constants (LITERAL1)
+#######################################

libraries/PDM/library.properties

@@ -0,0 +1,9 @@
+name=PDM
+version=1.0
+author=Arduino
+maintainer=Arduino <info@arduino.cc>
+sentence=Enables the communication with devices that use the PDM Bus. Specific implementation for nRF52.
+paragraph=
+category=Communication
+url=
+architectures=rp2040

libraries/PDM/src/PDM.h

@@ -0,0 +1,68 @@
+/*
+  Copyright (c) 2019 Arduino LLC.  All right reserved.
+
+  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef _PDM_H_INCLUDED
+#define _PDM_H_INCLUDED
+
+#include <Arduino.h>
+//#include <pinDefinitions.h>
+
+#include "utility/PDMDoubleBuffer.h"
+
+class PDMClass
+{
+public:
+  PDMClass(int dinPin, int clkPin, int pwrPin);
+  virtual ~PDMClass();
+
+  int begin(int channels, int sampleRate);
+  void end();
+
+  virtual int available();
+  virtual int read(void* buffer, size_t size);
+
+  void onReceive(void(*)(void));
+
+  //PORTENTA_H7 min -12 max 51
+  //NANO 33 BLE SENSe min 0 max 80
+  void setGain(int gain);
+  void setBufferSize(int bufferSize);
+  size_t getBufferSize();
+
+// private:
+  void IrqHandler(bool halftranfer);
+
+private:
+  int _dinPin;
+  int _clkPin;
+  int _pwrPin;
+
+  int _channels;
+  int _samplerate;
+
+  int _gain;
+  int _init;
+
+  PDMDoubleBuffer _doubleBuffer;
+
+  void (*_onReceive)(void);
+};
+#ifdef PIN_PDM_DIN
+extern PDMClass PDM;
+#endif
+#endif

libraries/PDM/src/rp2040/OpenPDMFilter.c

@@ -0,0 +1,313 @@
+/**
+ *******************************************************************************
+ * @file    OpenPDMFilter.c
+ * @author  CL
+ * @version V1.0.0
+ * @date    9-September-2015
+ * @brief   Open PDM audio software decoding Library.   
+ *          This Library is used to decode and reconstruct the audio signal
+ *          produced by ST MEMS microphone (MP45Dxxx, MP34Dxxx). 
+ *******************************************************************************
+ * @attention
+ *
+ * <h2><center>&copy; COPYRIGHT 2018 STMicroelectronics</center></h2>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************
+ */
+
+
+/* Includes ------------------------------------------------------------------*/
+
+#include "OpenPDMFilter.h"
+
+
+/* Variables -----------------------------------------------------------------*/
+
+uint32_t div_const = 0;
+int64_t sub_const = 0;
+uint32_t sinc[DECIMATION_MAX * SINCN];
+uint32_t sinc1[DECIMATION_MAX];
+uint32_t sinc2[DECIMATION_MAX * 2];
+uint32_t coef[SINCN][DECIMATION_MAX];
+#ifdef USE_LUT
+int32_t lut[256][DECIMATION_MAX / 8][SINCN];
+#endif
+
+
+/* Functions -----------------------------------------------------------------*/
+
+#ifdef USE_LUT
+int32_t filter_table_mono_64(uint8_t *data, uint8_t sincn)
+{
+  return (int32_t)
+    lut[data[0]][0][sincn] +
+    lut[data[1]][1][sincn] +
+    lut[data[2]][2][sincn] +
+    lut[data[3]][3][sincn] +
+    lut[data[4]][4][sincn] +
+    lut[data[5]][5][sincn] +
+    lut[data[6]][6][sincn] +
+    lut[data[7]][7][sincn];
+}
+int32_t filter_table_stereo_64(uint8_t *data, uint8_t sincn)
+{
+  return (int32_t)
+    lut[data[0]][0][sincn] +
+    lut[data[2]][1][sincn] +
+    lut[data[4]][2][sincn] +
+    lut[data[6]][3][sincn] +
+    lut[data[8]][4][sincn] +
+    lut[data[10]][5][sincn] +
+    lut[data[12]][6][sincn] +
+    lut[data[14]][7][sincn];
+}
+int32_t filter_table_mono_128(uint8_t *data, uint8_t sincn)
+{
+  return (int32_t)
+    lut[data[0]][0][sincn] +
+    lut[data[1]][1][sincn] +
+    lut[data[2]][2][sincn] +
+    lut[data[3]][3][sincn] +
+    lut[data[4]][4][sincn] +
+    lut[data[5]][5][sincn] +
+    lut[data[6]][6][sincn] +
+    lut[data[7]][7][sincn] +
+    lut[data[8]][8][sincn] +
+    lut[data[9]][9][sincn] +
+    lut[data[10]][10][sincn] +
+    lut[data[11]][11][sincn] +
+    lut[data[12]][12][sincn] +
+    lut[data[13]][13][sincn] +
+    lut[data[14]][14][sincn] +
+    lut[data[15]][15][sincn];
+}
+int32_t filter_table_stereo_128(uint8_t *data, uint8_t sincn)
+{
+  return (int32_t)
+    lut[data[0]][0][sincn] +
+    lut[data[2]][1][sincn] +
+    lut[data[4]][2][sincn] +
+    lut[data[6]][3][sincn] +
+    lut[data[8]][4][sincn] +
+    lut[data[10]][5][sincn] +
+    lut[data[12]][6][sincn] +
+    lut[data[14]][7][sincn] +
+    lut[data[16]][8][sincn] +
+    lut[data[18]][9][sincn] +
+    lut[data[20]][10][sincn] +
+    lut[data[22]][11][sincn] +
+    lut[data[24]][12][sincn] +
+    lut[data[26]][13][sincn] +
+    lut[data[28]][14][sincn] +
+    lut[data[30]][15][sincn];
+}
+int32_t (* filter_tables_64[2]) (uint8_t *data, uint8_t sincn) = {filter_table_mono_64, filter_table_stereo_64};
+int32_t (* filter_tables_128[2]) (uint8_t *data, uint8_t sincn) = {filter_table_mono_128, filter_table_stereo_128};
+#else
+int32_t filter_table(uint8_t *data, uint8_t sincn, TPDMFilter_InitStruct *param)
+{
+  uint8_t c, i;
+  uint16_t data_index = 0;
+  uint32_t *coef_p = &coef[sincn][0];
+  int32_t F = 0;
+  uint8_t decimation = param->Decimation;
+  uint8_t channels = param->In_MicChannels;
+
+  for (i = 0; i < decimation; i += 8) {
+    c = data[data_index];
+    F += ((c >> 7)       ) * coef_p[i    ] +
+         ((c >> 6) & 0x01) * coef_p[i + 1] +
+         ((c >> 5) & 0x01) * coef_p[i + 2] +
+         ((c >> 4) & 0x01) * coef_p[i + 3] +
+         ((c >> 3) & 0x01) * coef_p[i + 4] +
+         ((c >> 2) & 0x01) * coef_p[i + 5] +
+         ((c >> 1) & 0x01) * coef_p[i + 6] +
+         ((c     ) & 0x01) * coef_p[i + 7];
+    data_index += channels;
+  }
+  return F;
+}
+#endif
+
+void convolve(uint32_t Signal[/* SignalLen */], unsigned short SignalLen,
+              uint32_t Kernel[/* KernelLen */], unsigned short KernelLen,
+              uint32_t Result[/* SignalLen + KernelLen - 1 */])
+{
+  uint16_t n;
+
+  for (n = 0; n < SignalLen + KernelLen - 1; n++)
+  {
+    unsigned short kmin, kmax, k;
+    
+    Result[n] = 0;
+    
+    kmin = (n >= KernelLen - 1) ? n - (KernelLen - 1) : 0;
+    kmax = (n < SignalLen - 1) ? n : SignalLen - 1;
+    
+    for (k = kmin; k <= kmax; k++) {
+      Result[n] += Signal[k] * Kernel[n - k];
+    }
+  }
+}
+
+void Open_PDM_Filter_Init(TPDMFilter_InitStruct *Param)
+{
+  uint16_t i, j;
+  int64_t sum = 0;
+
+  uint8_t decimation = Param->Decimation;
+
+  for (i = 0; i < SINCN; i++) {
+    Param->Coef[i] = 0;
+    Param->bit[i] = 0;
+  }
+  for (i = 0; i < decimation; i++) {
+    sinc1[i] = 1;
+  }
+
+  Param->OldOut = Param->OldIn = Param->OldZ = 0;
+  Param->LP_ALFA = (Param->LP_HZ != 0 ? (uint16_t) (Param->LP_HZ * 256 / (Param->LP_HZ + Param->Fs / (2 * 3.14159))) : 0);
+  Param->HP_ALFA = (Param->HP_HZ != 0 ? (uint16_t) (Param->Fs * 256 / (2 * 3.14159 * Param->HP_HZ + Param->Fs)) : 0);
+
+  Param->FilterLen = decimation * SINCN;       
+  sinc[0] = 0;
+  sinc[decimation * SINCN - 1] = 0;      
+  convolve(sinc1, decimation, sinc1, decimation, sinc2);
+  convolve(sinc2, decimation * 2 - 1, sinc1, decimation, &sinc[1]);     
+  for(j = 0; j < SINCN; j++) {
+    for (i = 0; i < decimation; i++) {
+      coef[j][i] = sinc[j * decimation + i];
+      sum += sinc[j * decimation + i];
+    }
+  }
+
+  sub_const = sum >> 1;
+  div_const = sub_const * Param->MaxVolume / 32768 / Param->filterGain;
+  div_const = (div_const == 0 ? 1 : div_const);
+
+#ifdef USE_LUT
+  /* Look-Up Table. */
+  uint16_t c, d, s;
+  for (s = 0; s < SINCN; s++)
+  {
+    uint32_t *coef_p = &coef[s][0];
+    for (c = 0; c < 256; c++)
+      for (d = 0; d < decimation / 8; d++)
+        lut[c][d][s] = ((c >> 7)       ) * coef_p[d * 8    ] +
+                       ((c >> 6) & 0x01) * coef_p[d * 8 + 1] +
+                       ((c >> 5) & 0x01) * coef_p[d * 8 + 2] +
+                       ((c >> 4) & 0x01) * coef_p[d * 8 + 3] +
+                       ((c >> 3) & 0x01) * coef_p[d * 8 + 4] +
+                       ((c >> 2) & 0x01) * coef_p[d * 8 + 5] +
+                       ((c >> 1) & 0x01) * coef_p[d * 8 + 6] +
+                       ((c     ) & 0x01) * coef_p[d * 8 + 7];
+  }
+#endif
+}
+
+void Open_PDM_Filter_64(uint8_t* data, int16_t* dataOut, uint16_t volume, TPDMFilter_InitStruct *Param)
+{
+  uint8_t i, data_out_index;
+  uint8_t channels = Param->In_MicChannels;
+  uint8_t data_inc = ((DECIMATION_MAX >> 4) * channels);
+  int64_t Z, Z0, Z1, Z2;
+  int64_t OldOut, OldIn, OldZ;
+
+  OldOut = Param->OldOut;
+  OldIn = Param->OldIn;
+  OldZ = Param->OldZ;
+
+#ifdef USE_LUT
+  uint8_t j = channels - 1;
+#endif
+
+  for (i = 0, data_out_index = 0; i < Param->nSamples; i++, data_out_index += channels) {
+#ifdef USE_LUT
+    Z0 = filter_tables_64[j](data, 0);
+    Z1 = filter_tables_64[j](data, 1);
+    Z2 = filter_tables_64[j](data, 2);
+#else
+    Z0 = filter_table(data, 0, Param);
+    Z1 = filter_table(data, 1, Param);
+    Z2 = filter_table(data, 2, Param);
+#endif
+
+    Z = Param->Coef[1] + Z2 - sub_const;
+    Param->Coef[1] = Param->Coef[0] + Z1;
+    Param->Coef[0] = Z0;
+
+    OldOut = (Param->HP_ALFA * (OldOut + Z - OldIn)) >> 8;
+    OldIn = Z;
+    OldZ = ((256 - Param->LP_ALFA) * OldZ + Param->LP_ALFA * OldOut) >> 8;
+
+    Z = OldZ * volume;
+    Z = RoundDiv(Z, div_const);
+    Z = SaturaLH(Z, -32700, 32700);
+
+    dataOut[data_out_index] = Z;
+    data += data_inc;
+  }
+
+  Param->OldOut = OldOut;
+  Param->OldIn = OldIn;
+  Param->OldZ = OldZ;
+}
+
+void Open_PDM_Filter_128(uint8_t* data, int16_t* dataOut, uint16_t volume, TPDMFilter_InitStruct *Param)
+{
+  uint8_t i, data_out_index;
+  uint8_t channels = Param->In_MicChannels;
+  uint8_t data_inc = ((DECIMATION_MAX >> 3) * channels);
+  int64_t Z, Z0, Z1, Z2;
+  int64_t OldOut, OldIn, OldZ;
+
+  OldOut = Param->OldOut;
+  OldIn = Param->OldIn;
+  OldZ = Param->OldZ;
+
+#ifdef USE_LUT
+  uint8_t j = channels - 1;
+#endif
+
+  for (i = 0, data_out_index = 0; i < Param->nSamples; i++, data_out_index += channels) {
+#ifdef USE_LUT
+    Z0 = filter_tables_128[j](data, 0);
+    Z1 = filter_tables_128[j](data, 1);
+    Z2 = filter_tables_128[j](data, 2);
+#else
+    Z0 = filter_table(data, 0, Param);
+    Z1 = filter_table(data, 1, Param);
+    Z2 = filter_table(data, 2, Param);
+#endif
+
+    Z = Param->Coef[1] + Z2 - sub_const;
+    Param->Coef[1] = Param->Coef[0] + Z1;
+    Param->Coef[0] = Z0;
+
+    OldOut = (Param->HP_ALFA * (OldOut + Z - OldIn)) >> 8;
+    OldIn = Z;
+    OldZ = ((256 - Param->LP_ALFA) * OldZ + Param->LP_ALFA * OldOut) >> 8;
+
+    Z = OldZ * volume;
+    Z = RoundDiv(Z, div_const);
+    Z = SaturaLH(Z, -32700, 32700);
+
+    dataOut[data_out_index] = Z;
+    data += data_inc;
+  }
+
+  Param->OldOut = OldOut;
+  Param->OldIn = OldIn;
+  Param->OldZ = OldZ;
+}

libraries/PDM/src/rp2040/OpenPDMFilter.h

@@ -0,0 +1,99 @@
+/**
+ *******************************************************************************
+ * @file    OpenPDMFilter.h
+ * @author  CL
+ * @version V1.0.0
+ * @date    9-September-2015
+ * @brief   Header file for Open PDM audio software decoding Library.   
+ *          This Library is used to decode and reconstruct the audio signal
+ *          produced by ST MEMS microphone (MP45Dxxx, MP34Dxxx). 
+ *******************************************************************************
+ * @attention
+ *
+ * <h2><center>&copy; COPYRIGHT 2018 STMicroelectronics</center></h2>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *******************************************************************************
+ */
+
+
+/* Define to prevent recursive inclusion -------------------------------------*/
+
+#ifndef __OPENPDMFILTER_H
+#define __OPENPDMFILTER_H
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+
+
+/* Includes ------------------------------------------------------------------*/
+
+#include <stdint.h>
+
+
+/* Definitions ---------------------------------------------------------------*/
+
+/*
+ * Enable to use a Look-Up Table to improve performances while using more FLASH
+ * and RAM memory.
+ * Note: Without Look-Up Table up to stereo@16KHz configuration is supported.
+ */
+#define USE_LUT
+
+#define SINCN            3
+#define DECIMATION_MAX 128
+
+#define HTONS(A) ((((uint16_t)(A) & 0xff00) >> 8) | \
+                 (((uint16_t)(A) & 0x00ff) << 8))
+#define RoundDiv(a, b)    (((a)>0)?(((a)+(b)/2)/(b)):(((a)-(b)/2)/(b)))
+#define SaturaLH(N, L, H) (((N)<(L))?(L):(((N)>(H))?(H):(N)))
+
+
+/* Types ---------------------------------------------------------------------*/
+
+typedef struct {
+  /* Public */
+  float LP_HZ;
+  float HP_HZ;
+  uint16_t Fs;
+  unsigned int nSamples;
+  uint8_t In_MicChannels;
+  uint8_t Out_MicChannels;
+  uint8_t Decimation;
+  uint8_t MaxVolume;
+  /* Private */
+  uint32_t Coef[SINCN];
+  uint16_t FilterLen;
+  int64_t OldOut, OldIn, OldZ;
+  uint16_t LP_ALFA;
+  uint16_t HP_ALFA;
+  uint16_t bit[5];
+  uint16_t byte;
+  uint16_t filterGain;
+} TPDMFilter_InitStruct;
+
+
+/* Exported functions ------------------------------------------------------- */
+
+void Open_PDM_Filter_Init(TPDMFilter_InitStruct *init_struct);
+void Open_PDM_Filter_64(uint8_t* data, int16_t* data_out, uint16_t mic_gain, TPDMFilter_InitStruct *init_struct);
+void Open_PDM_Filter_128(uint8_t* data, int16_t* data_out, uint16_t mic_gain, TPDMFilter_InitStruct *init_struct);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __OPENPDMFILTER_H
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

libraries/PDM/src/rp2040/PDM.cpp

@@ -0,0 +1,205 @@
+
+
+#include "Arduino.h"
+#include "PDM.h"
+#include "OpenPDMFilter.h"
+
+extern "C" {
+#include "hardware/pio.h"
+#include "hardware/dma.h"
+#include "hardware/clocks.h"
+}
+#include "hardware/sync.h" 
+#include "pdm.pio.h"
+
+// Hardware peripherals used
+uint dmaChannel = 0;
+PIO pio = pio0;
+uint sm = 0;
+
+// raw buffers contain PDM data
+#define RAW_BUFFER_SIZE 512 // should be a multiple of (decimation / 8)
+uint8_t rawBuffer0[RAW_BUFFER_SIZE];
+uint8_t rawBuffer1[RAW_BUFFER_SIZE];
+uint8_t* rawBuffer[2] = {rawBuffer0, rawBuffer1};
+volatile int rawBufferIndex = 0; 
+
+int decimation = 64;
+
+// final buffer is the one to be filled with PCM data
+int16_t* volatile finalBuffer;
+
+// OpenPDM filter used to convert PDM into PCM
+#define FILTER_GAIN     16
+TPDMFilter_InitStruct filter;
+
+extern "C" {
+  __attribute__((__used__)) void dmaHandler(void)
+  {
+    PDM.IrqHandler(true);
+  }
+}
+
+
+PDMClass::PDMClass(int dinPin, int clkPin, int pwrPin) :
+  _dinPin(dinPin),
+  _clkPin(clkPin),
+  _pwrPin(pwrPin),
+  _onReceive(NULL),
+  _gain(-1),
+  _channels(-1),
+  _samplerate(-1),
+  _init(-1)
+{
+}
+
+PDMClass::~PDMClass()
+{
+}
+
+int PDMClass::begin(int channels, int sampleRate)
+{
+  //_channels = channels; // only one channel available
+
+  // clear the final buffers
+  _doubleBuffer.reset();
+  finalBuffer = (int16_t*)_doubleBuffer.data();
+  int finalBufferLength = _doubleBuffer.availableForWrite() / sizeof(int16_t);
+  _doubleBuffer.swap(0);
+
+  int rawBufferLength = RAW_BUFFER_SIZE / (decimation / 8);
+  // Saturate number of samples. Remaining bytes are dropped.
+  if (rawBufferLength > finalBufferLength) {
+    rawBufferLength = finalBufferLength;
+  }
+
+  /* Initialize Open PDM library */
+  filter.Fs = sampleRate;
+  filter.nSamples = rawBufferLength;
+  filter.LP_HZ = sampleRate/2;
+  filter.HP_HZ = 10;
+  filter.In_MicChannels = 1;
+  filter.Out_MicChannels = 1;
+  filter.Decimation = decimation;
+  if(_gain == -1) {
+    _gain = FILTER_GAIN;
+  }
+  filter.filterGain = _gain;
+  Open_PDM_Filter_Init(&filter);
+
+  // Configure PIO state machine
+  float clkDiv = (float)clock_get_hz(clk_sys) / sampleRate / decimation / 2; 
+  uint offset = pio_add_program(pio, &pdm_pio_program);
+  pdm_pio_program_init(pio, sm, offset, _clkPin, _dinPin, clkDiv);
+
+  // Wait for microphone 
+  delay(100);
+
+  // Configure DMA for transferring PIO rx buffer to raw buffers
+  dma_channel_config c = dma_channel_get_default_config(dmaChannel);
+  channel_config_set_read_increment(&c, false);
+  channel_config_set_write_increment(&c, true);
+  channel_config_set_dreq(&c, pio_get_dreq(pio, sm, false));
+  channel_config_set_transfer_data_size(&c, DMA_SIZE_8);
+
+  // Clear DMA interrupts
+  dma_hw->ints0 = 1u << dmaChannel; 
+  // Enable DMA interrupts
+  dma_channel_set_irq0_enabled(dmaChannel, true);
+  irq_set_exclusive_handler(DMA_IRQ_0, dmaHandler);
+  irq_set_enabled(DMA_IRQ_0, true);
+
+  dma_channel_configure(dmaChannel, &c,
+    rawBuffer[rawBufferIndex],        // Destinatinon pointer
+    &pio->rxf[sm],      // Source pointer
+    RAW_BUFFER_SIZE, // Number of transfers
+    true                // Start immediately
+  );
+
+  _init = 1;
+
+  return 1;
+}
+
+void PDMClass::end()
+{
+  dma_channel_abort(dmaChannel);
+  pinMode(_clkPin, INPUT);
+}
+
+int PDMClass::available()
+{
+  //NVIC_DisableIRQ(DMA_IRQ_0n);
+  //uint32_t interrupts = save_and_disable_interrupts();
+	irq_set_enabled(DMA_IRQ_0, false);
+  size_t avail = _doubleBuffer.available();
+  irq_set_enabled(DMA_IRQ_0, true);
+  //restore_interrupts(interrupts);
+  //NVIC_EnableIRQ(DMA_IRQ_0n);
+  return avail;
+}
+
+int PDMClass::read(void* buffer, size_t size)
+{
+	irq_set_enabled(DMA_IRQ_0, false);
+  int read = _doubleBuffer.read(buffer, size);
+  irq_set_enabled(DMA_IRQ_0, true);
+  return read;
+}
+
+void PDMClass::onReceive(void(*function)(void))
+{
+  _onReceive = function;
+}
+
+void PDMClass::setGain(int gain)
+{
+  _gain = gain;
+  if(_init == 1) {
+    filter.filterGain = _gain;
+    Open_PDM_Filter_Init(&filter);
+  }
+}
+
+void PDMClass::setBufferSize(int bufferSize)
+{
+  _doubleBuffer.setSize(bufferSize);
+}
+
+void PDMClass::IrqHandler(bool halftranfer)
+{
+  static int cutSamples = 100;
+
+  // Clear the interrupt request.
+  dma_hw->ints0 = 1u << dmaChannel; 
+  // Restart dma pointing to the other buffer 
+  int shadowIndex = rawBufferIndex ^ 1;
+  dma_channel_set_write_addr(dmaChannel, rawBuffer[shadowIndex], true);
+
+  if (_doubleBuffer.available()) {
+    // buffer overflow, stop
+    return end();
+  }
+
+  // fill final buffer with PCM samples
+  Open_PDM_Filter_64(rawBuffer[rawBufferIndex], finalBuffer, 1, &filter);
+
+  if (cutSamples) {
+    memset(finalBuffer, 0, cutSamples);
+    cutSamples = 0;
+  }
+
+  // swap final buffer and raw buffers' indexes
+  finalBuffer = (int16_t*)_doubleBuffer.data();
+  _doubleBuffer.swap(filter.nSamples * sizeof(int16_t));
+  rawBufferIndex = shadowIndex;
+
+  if (_onReceive) {
+    _onReceive();
+  }
+}
+#ifdef PIN_PDM_DIN
+PDMClass PDM(PIN_PDM_DIN, PIN_PDM_CLK, -1);
+#endif // PIN_PDM_DIN
+
+

libraries/PDM/src/rp2040/pdm.pio

@@ -0,0 +1,41 @@
+
+.program pdm_pio
+.side_set 1
+.wrap_target
+
+  ; prova a cambiare edge
+
+  ;sample on falling edge
+  push iffull noblock  side 1 
+  ;nop  side 1 
+  ;nop  side 0 
+  in pins, 1  side 0 
+  ;nop side 0
+  
+.wrap
+
+% c-sdk {
+#include "hardware/gpio.h"
+
+static inline void pdm_pio_program_init(PIO pio, uint sm, uint offset, uint clkPin, uint dataPin, float clkDiv) {
+  pio_sm_config c = pdm_pio_program_get_default_config(offset);
+  sm_config_set_sideset(&c, 1, false, false);
+  //sm_config_set_in_shift(&c, false, true, 8);
+  sm_config_set_in_shift(&c, false, false, 8);
+
+  sm_config_set_in_pins(&c, dataPin);
+  sm_config_set_sideset_pins(&c, clkPin);
+  sm_config_set_clkdiv(&c, clkDiv);
+
+  pio_sm_set_consecutive_pindirs(pio, sm, dataPin, 1, false);
+  pio_sm_set_consecutive_pindirs(pio, sm, clkPin, 1, true);
+  pio_sm_set_pins_with_mask(pio, sm, 0, (1u << clkPin) );
+  //pio_gpio_init(pio, dataPin);
+  pio_gpio_init(pio, clkPin);
+
+  pio_sm_init(pio, sm, offset, &c);
+  pio_sm_set_enabled(pio, sm, true);
+}
+
+
+%}

libraries/PDM/src/rp2040/pdm.pio.h

@@ -0,0 +1,56 @@
+// -------------------------------------------------- //
+// This file is autogenerated by pioasm; do not edit! //
+// -------------------------------------------------- //
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// ------- //
+// pdm_pio //
+// ------- //
+
+#define pdm_pio_wrap_target 0
+#define pdm_pio_wrap 1
+
+static const uint16_t pdm_pio_program_instructions[] = {
+            //     .wrap_target
+    0x9040, //  0: push   iffull noblock  side 1     
+    0x4001, //  1: in     pins, 1         side 0     
+            //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program pdm_pio_program = {
+    .instructions = pdm_pio_program_instructions,
+    .length = 2,
+    .origin = -1,
+};
+
+static inline pio_sm_config pdm_pio_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + pdm_pio_wrap_target, offset + pdm_pio_wrap);
+    sm_config_set_sideset(&c, 1, false, false);
+    return c;
+}
+
+#include "hardware/gpio.h"
+static inline void pdm_pio_program_init(PIO pio, uint sm, uint offset, uint clkPin, uint dataPin, float clkDiv) {
+  pio_sm_config c = pdm_pio_program_get_default_config(offset);
+  sm_config_set_sideset(&c, 1, false, false);
+  //sm_config_set_in_shift(&c, false, true, 8);
+  sm_config_set_in_shift(&c, false, false, 8);
+  sm_config_set_in_pins(&c, dataPin);
+  sm_config_set_sideset_pins(&c, clkPin);
+  sm_config_set_clkdiv(&c, clkDiv);
+  pio_sm_set_consecutive_pindirs(pio, sm, dataPin, 1, false);
+  pio_sm_set_consecutive_pindirs(pio, sm, clkPin, 1, true);
+  pio_sm_set_pins_with_mask(pio, sm, 0, (1u << clkPin) );
+  //pio_gpio_init(pio, dataPin);
+  pio_gpio_init(pio, clkPin);
+  pio_sm_init(pio, sm, offset, &c);
+  pio_sm_set_enabled(pio, sm, true);
+}
+
+#endif
+

libraries/PDM/src/utility/PDMDoubleBuffer.cpp

@@ -0,0 +1,139 @@
+/*
+  Copyright (c) 2016 Arduino LLC.  All right reserved.
+
+  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "PDMDoubleBuffer.h"
+
+PDMDoubleBuffer::PDMDoubleBuffer() :
+  _size(DEFAULT_PDM_BUFFER_SIZE)
+{
+  reset();
+}
+
+PDMDoubleBuffer::~PDMDoubleBuffer()
+{
+}
+
+void PDMDoubleBuffer::setSize(int size)
+{
+  _size = size;
+  reset();
+}
+
+size_t PDMDoubleBuffer::getSize()
+{
+  return _size;
+}
+
+void PDMDoubleBuffer::reset()
+{
+  _buffer[0] = (uint8_t*)realloc(_buffer[0], _size);
+  _buffer[1] = (uint8_t*)realloc(_buffer[1], _size);
+
+  memset(_buffer[0], 0x00, _size);
+  memset(_buffer[1], 0x00, _size);
+
+  _index = 0;
+  _length[0] = 0;
+  _length[1] = 0;
+  _readOffset[0] = 0;
+  _readOffset[1] = 0;
+}
+
+size_t PDMDoubleBuffer::availableForWrite()
+{
+  return (_size - (_length[_index] - _readOffset[_index]));
+}
+
+size_t PDMDoubleBuffer::write(const void *buffer, size_t size)
+{
+  size_t space = availableForWrite();
+
+  if (size > space) {
+    size = space;
+  }
+
+  if (size == 0) {
+    return 0;
+  }
+
+  memcpy(&_buffer[_index][_length[_index]], buffer, size);
+
+  _length[_index] += size;
+
+  return size;
+}
+
+size_t PDMDoubleBuffer::read(void *buffer, size_t size)
+{
+  size_t avail = available();
+
+  if (size > avail) {
+    size = avail;
+  }
+
+  if (size == 0) {
+    return 0;
+  }
+
+  memcpy(buffer, &_buffer[_index][_readOffset[_index]], size);
+  _readOffset[_index] += size;
+
+  return size;
+}
+
+size_t PDMDoubleBuffer::peek(void *buffer, size_t size)
+{
+  size_t avail = available();
+
+  if (size > avail) {
+    size = avail;
+  }
+
+  if (size == 0) {
+    return 0;
+  }
+
+  memcpy(buffer, &_buffer[_index][_readOffset[_index]], size);
+
+  return size;
+}
+
+void* PDMDoubleBuffer::data()
+{
+  return (void*)_buffer[_index];
+}
+
+size_t PDMDoubleBuffer::available()
+{
+  return _length[_index] - _readOffset[_index];
+}
+
+void PDMDoubleBuffer::swap(int length)
+{
+  if (_index == 0) {
+    _index = 1;
+  } else {
+    _index = 0;
+  }
+
+  _length[_index] = length;
+  _readOffset[_index] = 0;
+}

libraries/PDM/src/utility/PDMDoubleBuffer.h

@@ -0,0 +1,54 @@
+/*
+  Copyright (c) 2016 Arduino LLC.  All right reserved.
+
+  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef _PDM_DOUBLE_BUFFER_H_INCLUDED
+#define _PDM_DOUBLE_BUFFER_H_INCLUDED
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define DEFAULT_PDM_BUFFER_SIZE 512
+
+class PDMDoubleBuffer
+{
+public:
+  PDMDoubleBuffer();
+  virtual ~PDMDoubleBuffer();
+
+  void setSize(int size);
+  size_t getSize();
+
+  void reset();
+
+  size_t availableForWrite();
+  size_t write(const void *buffer, size_t size);
+  size_t read(void *buffer, size_t size);
+  size_t peek(void *buffer, size_t size);
+  void* data();
+  size_t available();
+  void swap(int length = 0);
+
+private:
+  uint8_t* _buffer[2] __attribute__((aligned (16)));
+  int _size;
+  volatile int _length[2];
+  volatile int _readOffset[2];
+  volatile int _index; 
+};
+
+#endif

libraries/SDFS/src/SDFS.h

@@ -234,8 +234,8 @@ protected:
     }
 
 
-    static uint8_t _getFlags(OpenMode openMode, AccessMode accessMode) {
-        uint8_t mode = 0;
+    static int _getFlags(OpenMode openMode, AccessMode accessMode) {
+        int mode = 0;
         if (openMode & OM_CREATE) {
             mode |= O_CREAT;
         }

libraries/Wire/Wire.cpp

@@ -123,7 +123,7 @@ void TwoWire::begin(uint8_t addr) {
     i2c_set_slave_mode(_i2c, true, addr);
 
     // Our callback IRQ
-    _i2c->hw->intr_mask = (1 << 10) | (1 << 9) | (1 << 5) | (1 << 2);
+    _i2c->hw->intr_mask = (1 << 10) | (1 << 9) | (1 << 6) | (1 << 5) | (1 << 2);
 
     int irqNo = I2C0_IRQ + i2c_hw_index(_i2c);
     irq_set_exclusive_handler(irqNo, i2c_hw_index(_i2c) == 0 ? _handler0 : _handler1);
@@ -139,6 +139,7 @@ void TwoWire::begin(uint8_t addr) {
 }
 
 void TwoWire::onIRQ() {
+    Serial.printf("Wire.IRQ=%08x\n", _i2c->hw->intr_stat);
     if (_i2c->hw->intr_stat & (1 << 10)) {
         _buffLen = 0;
         _buffOff = 0;
@@ -154,6 +155,10 @@ void TwoWire::onIRQ() {
         _slaveStartDet = false;
         _i2c->hw->clr_stop_det;
     }
+    if (_i2c->hw->intr_stat & (1 << 6)) {
+        // TX_ABRT
+        _i2c->hw->clr_tx_abrt;
+    }
     if (_i2c->hw->intr_stat & (1 << 5)) {
         // RD_REQ
         if (_onRequestCallback) {

tests/common.sh

@@ -26,6 +26,7 @@ function skip_ino()
 /p08_DigitalHourglass/
 /p13_TouchSensorLamp/
 /StringComparisonOperators/
+/PDMSerialPlotter/
 EOL
     echo $ino | grep -q -F "$skiplist"
     echo $(( 1 - $? ))

variants/arduino_nano_connect/pins_arduino.h

@@ -102,6 +102,11 @@ static const uint8_t SCK = PIN_SPI0_SCK;
 #define SPIWIFI_RESET	(NINA_RESETN)
 #define SPIWIFI 		(SPI1)
 
+// PDM Interfaces
+// ---------------
+#define PIN_PDM_CLK	 (D23)
+#define PIN_PDM_DIN	 (D22)
+
 //Cose copiate a caso
 
 #define SERIAL_PORT_USBVIRTUAL      SerialUSB