Diff: Adafruit_APDS9960.cpp

Revision:

0:5d88688340fc

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Adafruit_APDS9960.cpp	Mon Jun 22 14:16:28 2020 +0000
@@ -0,0 +1,768 @@
+/*!
+ *  @file Adafruit_APDS9960.cpp
+ *
+ *  @mainpage Adafruit APDS9960 Proximity, Light, RGB, and Gesture Sensor
+ *
+ *  @section author Author
+ *
+ *  Ladyada, Dean Miller (Adafruit Industries)
+ *
+ *  @section license License
+ *
+ *  Software License Agreement (BSD License)
+ *
+ *  Copyright (c) 2017, Adafruit Industries
+ *  All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are met:
+ *  1. Redistributions of source code must retain the above copyright
+ *  notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *  notice, this list of conditions and the following disclaimer in the
+ *  documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the copyright holders nor the
+ *  names of its contributors may be used to endorse or promote products
+ *  derived from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
+ *  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
+ *  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ *  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef __AVR
+#include <avr/pgmspace.h>
+#elif defined(ESP8266)
+#include <pgmspace.h>
+#endif
+#include <math.h>
+#include <stdlib.h>
+
+#include "Adafruit_APDS9960.h"
+
+/*!
+ *  @brief  Implements missing powf function
+ *  @param  x
+ *          Base number
+ *  @param  y
+ *          Exponent
+ *  @return x raised to the power of y
+ */
+ /*
+float powf(const float x, const float y) {
+  return (float)(pow((double)x, (double)y));
+}
+*/
+
+/*!
+ *  @brief  Enables the device
+ *          Disables the device (putting it in lower power sleep mode)
+ *  @param  en
+ *          Enable (True/False)
+ */
+void Adafruit_APDS9960::enable(boolean en) {
+  _enable.PON = en;
+  this->write8(APDS9960_ENABLE, _enable.get());
+}
+
+/*!
+ *  @brief  Initializes I2C and configures the sensor
+ *  @param  iTimeMS
+ *          Integration time
+ *  @param  aGain
+ *          Gain
+ *  @param  addr
+ *          I2C address
+ *  @param  *theWire
+ *          Wire object
+ *  @return True if initialization was successful, otherwise false.
+ */
+boolean Adafruit_APDS9960::begin(I2C *theWire, uint16_t iTimeMS, apds9960AGain_t aGain,
+                                 uint8_t addr) {
+  _wire = theWire;
+  _i2c_init();
+  _i2caddr = addr;
+
+  /* Make sure we're actually connected */
+  uint8_t x = read8(APDS9960_ID);
+  if (x != 0xAB) {
+    return false;
+    _pc->printf("TESTCPP %d", x);
+  }
+
+  /* Set default integration time and gain */
+  setADCIntegrationTime(iTimeMS);
+  setADCGain(aGain);
+
+  // disable everything to start
+  enableGesture(false);
+  enableProximity(false);
+  enableColor(false);
+
+  disableColorInterrupt();
+  disableProximityInterrupt();
+  clearInterrupt();
+
+  /* Note: by default, the device is in power down mode on bootup */
+  enable(false);
+  wait_us(10000);
+  enable(true);
+  wait_us(10000);
+
+  // default to all gesture dimensions
+  setGestureDimensions(APDS9960_DIMENSIONS_ALL);
+  setGestureFIFOThreshold(APDS9960_GFIFO_4);
+  setGestureGain(APDS9960_GGAIN_4);
+  setGestureProximityThreshold(50);
+  resetCounts();
+
+  _gpulse.GPLEN = APDS9960_GPULSE_32US;
+  _gpulse.GPULSE = 9; // 10 pulses
+  this->write8(APDS9960_GPULSE, _gpulse.get());
+
+  return true;
+}
+
+/*!
+ *  @brief  Sets the integration time for the ADC of the APDS9960, in millis
+ *  @param  iTimeMS
+ *          Integration time
+ */
+void Adafruit_APDS9960::setADCIntegrationTime(uint16_t iTimeMS) {
+  float temp;
+
+  // convert ms into 2.78ms increments
+  temp = iTimeMS;
+  temp /= 2.78;
+  temp = 256 - temp;
+  if (temp > 255)
+    temp = 255;
+  if (temp < 0)
+    temp = 0;
+
+  /* Update the timing register */
+  write8(APDS9960_ATIME, (uint8_t)temp);
+}
+
+/*!
+ *  @brief  Returns the integration time for the ADC of the APDS9960, in millis
+ *  @return Integration time
+ */
+float Adafruit_APDS9960::getADCIntegrationTime() {
+  float temp;
+
+  temp = read8(APDS9960_ATIME);
+
+  // convert to units of 2.78 ms
+  temp = 256 - temp;
+  temp *= 2.78;
+  return temp;
+}
+
+/*!
+ *  @brief  Adjusts the color/ALS gain on the APDS9960 (adjusts the sensitivity
+ *          to light)
+ *  @param  aGain
+ *          Gain
+ */
+void Adafruit_APDS9960::setADCGain(apds9960AGain_t aGain) {
+  _control.AGAIN = aGain;
+
+  /* Update the timing register */
+  write8(APDS9960_CONTROL, _control.get());
+}
+
+/*!
+ *  @brief  Returns the ADC gain
+ *  @return ADC gain
+ */
+apds9960AGain_t Adafruit_APDS9960::getADCGain() {
+  return (apds9960AGain_t)(read8(APDS9960_CONTROL) & 0x03);
+}
+
+/*!
+ *  @brief  Adjusts the Proximity gain on the APDS9960
+ *  @param  pGain
+ *          Gain
+ */
+void Adafruit_APDS9960::setProxGain(apds9960PGain_t pGain) {
+  _control.PGAIN = pGain;
+
+  /* Update the timing register */
+  write8(APDS9960_CONTROL, _control.get());
+}
+
+/*!
+ *  @brief  Returns the Proximity gain on the APDS9960
+ *  @return Proxmity gain
+ */
+apds9960PGain_t Adafruit_APDS9960::getProxGain() {
+  return (apds9960PGain_t)(read8(APDS9960_CONTROL) & 0x0C);
+}
+
+/*!
+ *  @brief  Sets number of proxmity pulses
+ *  @param  pLen
+ *          Pulse Length
+ *  @param  pulses
+ *          Number of pulses
+ */
+void Adafruit_APDS9960::setProxPulse(apds9960PPulseLen_t pLen, uint8_t pulses) {
+  if (pulses < 1)
+    pulses = 1;
+  if (pulses > 64)
+    pulses = 64;
+  pulses--;
+
+  _ppulse.PPLEN = pLen;
+  _ppulse.PPULSE = pulses;
+
+  write8(APDS9960_PPULSE, _ppulse.get());
+}
+
+/*!
+ *  @brief  Enable proximity readings on APDS9960
+ *  @param  en
+ *          Enable (True/False)
+ */
+void Adafruit_APDS9960::enableProximity(boolean en) {
+  _enable.PEN = en;
+
+  write8(APDS9960_ENABLE, _enable.get());
+}
+
+/*!
+ *  @brief  Enable proximity interrupts
+ */
+void Adafruit_APDS9960::enableProximityInterrupt() {
+  _enable.PIEN = 1;
+  write8(APDS9960_ENABLE, _enable.get());
+  clearInterrupt();
+}
+
+/*!
+ *  @brief  Disable proximity interrupts
+ */
+void Adafruit_APDS9960::disableProximityInterrupt() {
+  _enable.PIEN = 0;
+  write8(APDS9960_ENABLE, _enable.get());
+}
+
+/*!
+ *  @brief  Set proxmity interrupt thresholds
+ *  @param  low
+ *          Low threshold
+ *  @param  high
+ *          High threshold
+ *  @param  persistance
+ *          Persistance
+ */
+void Adafruit_APDS9960::setProximityInterruptThreshold(uint8_t low,
+                                                       uint8_t high,
+                                                       uint8_t persistance) {
+  write8(APDS9960_PILT, low);
+  write8(APDS9960_PIHT, high);
+
+  if (persistance > 7)
+    persistance = 7;
+  _pers.PPERS = persistance;
+  write8(APDS9960_PERS, _pers.get());
+}
+
+/*!
+ *  @brief  Returns proxmity interrupt status
+ *  @return True if enabled, false otherwise.
+ */
+bool Adafruit_APDS9960::getProximityInterrupt() {
+  _status.set(this->read8(APDS9960_STATUS));
+  return _status.PINT;
+};
+
+/*!
+ *  @brief  Read proximity data
+ *  @return Proximity
+ */
+uint8_t Adafruit_APDS9960::readProximity() { return read8(APDS9960_PDATA); }
+
+/*!
+ *  @brief  Returns validity status of a gesture
+ *  @return Status (True/False)
+ */
+bool Adafruit_APDS9960::gestureValid() {
+  _gstatus.set(this->read8(APDS9960_GSTATUS));
+  return _gstatus.GVALID;
+}
+
+/*!
+ *  @brief  Sets gesture dimensions
+ *  @param  dims
+ *          Dimensions (APDS9960_DIMENSIONS_ALL, APDS9960_DIMENSIONS_UP_DOWM,
+ *          APDS9960_DIMENSIONS_UP_DOWN, APGS9960_DIMENSIONS_LEFT_RIGHT)
+ */
+void Adafruit_APDS9960::setGestureDimensions(uint8_t dims) {
+  _gconf3.GDIMS = dims;
+  this->write8(APDS9960_GCONF3, _gconf3.get());
+}
+
+/*!
+ *  @brief  Sets gesture FIFO Threshold
+ *  @param  thresh
+ *          Threshold (APDS9960_GFIFO_1, APDS9960_GFIFO_4, APDS9960_GFIFO_8,
+ *          APDS9960_GFIFO_16)
+ */
+void Adafruit_APDS9960::setGestureFIFOThreshold(uint8_t thresh) {
+  _gconf1.GFIFOTH = thresh;
+  this->write8(APDS9960_GCONF1, _gconf1.get());
+}
+
+/*!
+ *  @brief  Sets gesture sensor gain
+ *  @param  gain
+ *          Gain (APDS9960_GAIN_1, APDS9960_GAIN_2, APDS9960_GAIN_4,
+ *          APDS9960_GAIN_8)
+ */
+void Adafruit_APDS9960::setGestureGain(uint8_t gain) {
+  _gconf2.GGAIN = gain;
+  this->write8(APDS9960_GCONF2, _gconf2.get());
+}
+
+/*!
+ *  @brief  Sets gesture sensor threshold
+ *  @param  thresh
+ *          Threshold
+ */
+void Adafruit_APDS9960::setGestureProximityThreshold(uint8_t thresh) {
+  this->write8(APDS9960_GPENTH, thresh);
+}
+
+/*!
+ *  @brief  Sets gesture sensor offset
+ *  @param  offset_up
+ *          Up offset
+ *  @param  offset_down
+ *          Down offset
+ *  @param  offset_left
+ *          Left offset
+ *  @param  offset_right
+ *          Right offset
+ */
+void Adafruit_APDS9960::setGestureOffset(uint8_t offset_up, uint8_t offset_down,
+                                         uint8_t offset_left,
+                                         uint8_t offset_right) {
+  this->write8(APDS9960_GOFFSET_U, offset_up);
+  this->write8(APDS9960_GOFFSET_D, offset_down);
+  this->write8(APDS9960_GOFFSET_L, offset_left);
+  this->write8(APDS9960_GOFFSET_R, offset_right);
+}
+
+/*!
+ *  @brief  Enable gesture readings on APDS9960
+ *  @param  en
+ *          Enable (True/False)
+ */
+void Adafruit_APDS9960::enableGesture(boolean en) {
+  if (!en) {
+    _gconf4.GMODE = 0;
+    write8(APDS9960_GCONF4, _gconf4.get());
+  }
+  _enable.GEN = en;
+  write8(APDS9960_ENABLE, _enable.get());
+  resetCounts();
+}
+
+/*!
+ *  @brief  Resets gesture counts
+ */
+void Adafruit_APDS9960::resetCounts() {
+  gestCnt = 0;
+  UCount = 0;
+  DCount = 0;
+  LCount = 0;
+  RCount = 0;
+}
+
+/*!
+ *  @brief  Reads gesture
+ *  @return Received gesture (APDS9960_DOWN APDS9960_UP, APDS9960_LEFT
+ *          APDS9960_RIGHT)
+ */
+uint8_t Adafruit_APDS9960::readGesture() {
+  uint8_t toRead;
+  uint8_t buf[256];
+  unsigned long t = 0;
+  uint8_t gestureReceived;
+  while (1) {
+    int up_down_diff = 0;
+    int left_right_diff = 0;
+    gestureReceived = 0;
+    if (!gestureValid())
+      return 0;
+
+    wait_us(30000);
+    toRead = this->read8(APDS9960_GFLVL);
+
+    // produces sideffects needed for readGesture to work
+    this->read(APDS9960_GFIFO_U, buf, toRead);
+
+    if (abs((int)buf[0] - (int)buf[1]) > 13)
+      up_down_diff += (int)buf[0] - (int)buf[1];
+
+    if (abs((int)buf[2] - (int)buf[3]) > 13)
+      left_right_diff += (int)buf[2] - (int)buf[3];
+
+    if (up_down_diff != 0) {
+      if (up_down_diff < 0) {
+        if (DCount > 0) {
+          gestureReceived = APDS9960_UP;
+        } else
+          UCount++;
+      } else if (up_down_diff > 0) {
+        if (UCount > 0) {
+          gestureReceived = APDS9960_DOWN;
+        } else
+          DCount++;
+      }
+    }
+
+    if (left_right_diff != 0) {
+      if (left_right_diff < 0) {
+        if (RCount > 0) {
+          gestureReceived = APDS9960_LEFT;
+        } else
+          LCount++;
+      } else if (left_right_diff > 0) {
+        if (LCount > 0) {
+          gestureReceived = APDS9960_RIGHT;
+        } else
+          RCount++;
+      }
+    }
+
+
+    if (up_down_diff != 0 || left_right_diff != 0){
+      t = clock_ms(); 
+      }
+
+    if (gestureReceived || clock_ms() - t > 300) {
+      resetCounts();
+      return gestureReceived;
+    }
+    
+  }
+}
+
+/*!
+ *  @brief  Set LED brightness for proximity/gesture
+ *  @param  drive
+ *          LED Drive
+ *  @param  boost
+ *          LED Boost
+ */
+void Adafruit_APDS9960::setLED(apds9960LedDrive_t drive,
+                               apds9960LedBoost_t boost) {
+  // set BOOST
+  _config2.LED_BOOST = boost;
+  write8(APDS9960_CONFIG2, _config2.get());
+
+  _control.LDRIVE = drive;
+  write8(APDS9960_CONTROL, _control.get());
+}
+
+/*!
+ *  @brief  Enable color readings on APDS9960
+ *  @param  en
+ *          Enable (True/False)
+ */
+void Adafruit_APDS9960::enableColor(boolean en) {
+  _enable.AEN = en;
+  write8(APDS9960_ENABLE, _enable.get());
+}
+
+/*!
+ *  @brief  Returns status of color data
+ *  @return True if color data ready, False otherwise
+ */
+bool Adafruit_APDS9960::colorDataReady() {
+  _status.set(this->read8(APDS9960_STATUS));
+  return _status.AVALID;
+}
+
+/*!
+ *  @brief  Reads the raw red, green, blue and clear channel values
+ *  @param  *r
+ *          Red value
+ *  @param  *g
+ *          Green value
+ *  @param  *b
+ *          Blue value
+ *  @param  *c
+ *          Clear channel value
+ */
+void Adafruit_APDS9960::getColorData(uint16_t *r, uint16_t *g, uint16_t *b,
+                                     uint16_t *c) {
+
+  *c = read16R(APDS9960_CDATAL);
+  *r = read16R(APDS9960_RDATAL);
+  *g = read16R(APDS9960_GDATAL);
+  *b = read16R(APDS9960_BDATAL);
+}
+
+/*!
+ *  @brief  Converts the raw R/G/B values to color temperature in degrees Kelvin
+ *  @param  r
+ *          Red value
+ *  @param  g
+ *          Green value
+ *  @param  b
+ *          Blue value
+ *  @return Color temperature
+ */
+uint16_t Adafruit_APDS9960::calculateColorTemperature(uint16_t r, uint16_t g,
+                                                      uint16_t b) {
+  float X, Y, Z; /* RGB to XYZ correlation      */
+  float xc, yc;  /* Chromaticity co-ordinates   */
+  float n;       /* McCamy's formula            */
+  float cct;
+
+  /* 1. Map RGB values to their XYZ counterparts.    */
+  /* Based on 6500K fluorescent, 3000K fluorescent   */
+  /* and 60W incandescent values for a wide range.   */
+  /* Note: Y = Illuminance or lux                    */
+  X = (-0.14282F * r) + (1.54924F * g) + (-0.95641F * b);
+  Y = (-0.32466F * r) + (1.57837F * g) + (-0.73191F * b);
+  Z = (-0.68202F * r) + (0.77073F * g) + (0.56332F * b);
+
+  /* 2. Calculate the chromaticity co-ordinates      */
+  xc = (X) / (X + Y + Z);
+  yc = (Y) / (X + Y + Z);
+
+  /* 3. Use McCamy's formula to determine the CCT    */
+  n = (xc - 0.3320F) / (0.1858F - yc);
+
+  /* Calculate the final CCT */
+  cct =
+      (449.0F * powf(n, 3)) + (3525.0F * powf(n, 2)) + (6823.3F * n) + 5520.33F;
+
+  /* Return the results in degrees Kelvin */
+  return (uint16_t)cct;
+}
+
+/*!
+ *  @brief  Calculate ambient light values
+ *  @param  r
+ *          Red value
+ *  @param  g
+ *          Green value
+ *  @param  b
+ *          Blue value
+ *  @return LUX value
+ */
+uint16_t Adafruit_APDS9960::calculateLux(uint16_t r, uint16_t g, uint16_t b) {
+  float illuminance;
+
+  /* This only uses RGB ... how can we integrate clear or calculate lux */
+  /* based exclusively on clear since this might be more reliable?      */
+  illuminance = (-0.32466F * r) + (1.57837F * g) + (-0.73191F * b);
+
+  return (uint16_t)illuminance;
+}
+
+/*!
+ *  @brief  Enables color interrupt
+ */
+void Adafruit_APDS9960::enableColorInterrupt() {
+  _enable.AIEN = 1;
+  write8(APDS9960_ENABLE, _enable.get());
+}
+
+/*!
+ *  @brief  Disables color interrupt
+ */
+void Adafruit_APDS9960::disableColorInterrupt() {
+  _enable.AIEN = 0;
+  write8(APDS9960_ENABLE, _enable.get());
+}
+
+/*!
+ *  @brief  Clears interrupt
+ */
+void Adafruit_APDS9960::clearInterrupt() {
+  this->write(APDS9960_AICLEAR, NULL, 0);
+}
+
+/*!
+ *  @brief  Sets interrupt limits
+ *  @param  low
+ *          Low limit
+ *  @param  high
+ *          High limit
+ */
+void Adafruit_APDS9960::setIntLimits(uint16_t low, uint16_t high) {
+  write8(APDS9960_AILTIL, low & 0xFF);
+  write8(APDS9960_AILTH, low >> 8);
+  write8(APDS9960_AIHTL, high & 0xFF);
+  write8(APDS9960_AIHTH, high >> 8);
+}
+
+/*!
+ *  @brief  Writes specified value to given register
+ *  @param  reg
+ *          Register to write to
+ *  @param  value
+ *          Value to write
+ */
+void Adafruit_APDS9960::write8(byte reg, byte value) {
+  this->write(reg, &value, 1);
+}
+
+/*!
+ *  @brief  Reads 8 bits from specified register
+ *  @param  reg
+ *          Register to write to
+ *  @return Value in register
+ */
+uint8_t Adafruit_APDS9960::read8(byte reg) {
+  uint8_t ret;
+  this->read(reg, &ret, 1);
+
+  return ret;
+}
+
+/*!
+ *  @brief  Reads 32 bits from specified register
+ *  @param  reg
+ *          Register to write to
+ *  @return Value in register
+ */
+uint32_t Adafruit_APDS9960::read32(uint8_t reg) {
+  uint8_t ret[4];
+  uint32_t ret32;
+  this->read(reg, ret, 4);
+  ret32 = ret[3];
+  ret32 |= (uint32_t)ret[2] << 8;
+  ret32 |= (uint32_t)ret[1] << 16;
+  ret32 |= (uint32_t)ret[0] << 24;
+  return ret32;
+}
+
+/*!
+ *  @brief  Reads 16 bites from specified register
+ *  @param  reg
+ *          Register to write to
+ *  @return Value in register
+ */
+uint16_t Adafruit_APDS9960::read16(uint8_t reg) {
+  uint8_t ret[2];
+  this->read(reg, ret, 2);
+
+  return (ret[0] << 8) | ret[1];
+}
+
+/*!
+ *  @brief  Reads 16 bites from specified register
+ *  @param  reg
+ *          Register to write to
+ *  @return Value in register
+ */
+uint16_t Adafruit_APDS9960::read16R(uint8_t reg) {
+  uint8_t ret[2];
+  this->read(reg, ret, 2);
+
+  return (ret[1] << 8) | ret[0];
+}
+
+/*!
+ *  @brief  Begins I2C communication
+ */
+void Adafruit_APDS9960::_i2c_init() {
+    //_wire->begin();  // on mbed, we are already master if using the I2C class instead of I2CSlave class
+}
+
+/*!
+ *  @brief  Reads num bytes from specified register into a given buffer
+ *  @param  reg
+ *          Register
+ *  @param  *buf
+ *          Buffer
+ *  @param  num
+ *          Number of bytes
+ *  @return Position after reading
+ */
+uint8_t Adafruit_APDS9960::read(uint8_t reg, uint8_t *buf, uint8_t num) {
+  uint8_t pos = 0;
+  bool eof = false;
+
+  // on arduino we need to read in 32 byte chunks
+  //while (pos < num && !eof) {
+
+    //uint8_t read_now = min(32, num - pos);
+    /*
+    _wire->beginTransmission((uint8_t)_i2caddr);
+    _wire->write((uint8_t)reg + pos);
+    _wire->endTransmission();
+
+    _wire->requestFrom((uint8_t)_i2caddr, read_now);
+    */
+    
+    //_wire->start();
+    //_wire->write((uint8_t)_i2caddr);
+    //_wire->write((uint8_t)reg);
+    //_wire->stop();
+    
+    _wire->write((uint8_t)_i2caddr, (char *)&reg, 1, true);
+    
+    _wire->read((uint8_t)_i2caddr, (char *) buf, num);
+    
+    
+/*
+    for (int i = 0; i < read_now; i++) {
+      if (!_wire->available()) {
+        eof = true;
+        break;
+      }
+      buf[pos] = _wire->read();
+      pos++;
+    }
+    */
+  //}
+  
+  return num;
+}
+
+/*!
+ *  @brief  Writes num bytes from specified buffer into a given register
+ *  @param  reg
+ *          Register
+ *  @param  *buf
+ *          Buffer
+ *  @param  num
+ *          Number of bytes
+ */
+void Adafruit_APDS9960::write(uint8_t reg, uint8_t *buf, uint8_t num) {
+  /*
+  _wire->beginTransmission((uint8_t)_i2caddr);
+  _wire->write((uint8_t)reg);
+  _wire->write((uint8_t *)buf, num);
+  _wire->endTransmission();
+  */
+  
+  _wire->start();
+  _wire->write((uint8_t)_i2caddr);
+  _wire->write((uint8_t)reg);
+  
+  for(int i=0; i < num; i++){ // on parcours le "tableau" buf
+    uint8_t value = *(buf+i); // on récupere la valeur à l'emplacement "i" du tableau
+    _wire->write(value); // j'écris la valeur du tableau à l'emplacement "i" sur le bus i2c.
+  }
+  
+  _wire->stop();
+  
+  
+}
\ No newline at end of file