MPR121 & Axoloti (i2c)

/*
 MPR121 example to read touches
 by Paul 2016 irieelectronics.de

 main MPR121 code is from: http://bildr.org/2011/05/mpr121_arduino/
 */

// MPR121 Register Defines
#define     MHD_R   0x2B
#define     NHD_R   0x2C
#define NCL_R   0x2D
#define FDL_R   0x2E
#define MHD_F   0x2F
#define NHD_F   0x30
#define NCL_F   0x31
#define FDL_F   0x32
#define ELE0_T  0x41
#define ELE0_R  0x42
#define ELE1_T  0x43
#define ELE1_R  0x44
#define ELE2_T  0x45
#define ELE2_R  0x46
#define ELE3_T  0x47
#define ELE3_R  0x48
#define ELE4_T  0x49
#define ELE4_R  0x4A
#define ELE5_T  0x4B
#define ELE5_R  0x4C
#define ELE6_T  0x4D
#define ELE6_R  0x4E
#define ELE7_T  0x4F
#define ELE7_R  0x50
#define ELE8_T  0x51
#define ELE8_R  0x52
#define ELE9_T  0x53
#define ELE9_R  0x54
#define ELE10_T 0x55
#define ELE10_R 0x56
#define ELE11_T 0x57
#define ELE11_R 0x58
#define FIL_CFG 0x5D
#define ELE_CFG 0x5E
#define     GPIO_CTRL0  0x73
#define GPIO_CTRL1  0x74
#define     GPIO_DATA       0x75
#define GPIO_DIR        0x76
#define GPIO_EN     0x77
#define GPIO_SET        0x78
#define GPIO_CLEAR  0x79
#define GPIO_TOGGLE 0x7A
#define ATO_CFG0    0x7B
#define ATO_CFGU    0x7D
#define ATO_CFGL    0x7E
#define ATO_CFGT    0x7F


// Global Constants
#define     TOU_THRESH  0x06
#define REL_THRESH  0x0A

uint8_t *rxbuf;
uint8_t *txbuf;

// systime_t tmo = MS2ST(4);

uint8_t touchStates[12]; //to keep track of the previous touch states

void setup (void){
    static uint8_t _txbuf[8] __attribute__ ((section (".sram2")));
    static uint8_t _rxbuf[8] __attribute__ ((section (".sram2")));
    txbuf = _txbuf;
    rxbuf = _rxbuf;

    palSetPadMode(GPIOB, 1, PAL_MODE_INPUT_PULLUP);
    /*
    palSetPadMode(GPIOB, 8, PAL_MODE_ALTERNATE(4)|PAL_STM32_PUDR_PULLUP|PAL_STM32_OTYPE_OPENDRAIN);// SCL
        palSetPadMode(GPIOB, 9, PAL_MODE_ALTERNATE(4)|PAL_STM32_PUDR_PULLUP|PAL_STM32_OTYPE_OPENDRAIN);// SDA

        static const I2CConfig i2cfg = {
        OPMODE_I2C,
        400000,
        FAST_DUTY_CYCLE_2,
    };

    i2cStart(&I2CD1, &i2cfg);   // start I2C
    */
    mpr121_setup(); // call MPR121 Setup

    LogTextMessage("READY");
}

void loop (void){

    readTouchInputs();
    chThdSleepMilliseconds(1);

 }

void readTouchInputs(void){
  if(!checkInterrupt()){

    //read the touch state from the MPR121
    msg_t backmsg = i2cMasterReceive(&I2CD1, 0x5A, rxbuf, 2);

    uint8_t LSB = rxbuf[0];
    uint8_t MSB = rxbuf[1];

    uint16_t touched = ((MSB << 8) | LSB); //16bits that make up the touch states


    for (int i=0; i < 12; i++){  // Check what electrodes were pressed
      if(touched & (1<<i)){

        if(touchStates[i] == 0){
          //pin i was just touched
          LogTextMessage("pin: [%i] was just touched", i);          // LogTextMessage(" was just touched");

        }else if(touchStates[i] == 1){
          //pin i is still being touched
        }

        touchStates[i] = 1;
      }else{
        if(touchStates[i] == 1){
          LogTextMessage("pin: [%i] is no longer being touched", i);    //pin i is no longer being touched
       }
       touchStates[i] = 0;
      }
    }
  }
}


void mpr121_setup(void){

  set_register(0x5A, ELE_CFG, 0x00);

  // Section A - Controls filtering when data is > baseline.
  set_register(0x5A, MHD_R, 0x01);
  set_register(0x5A, NHD_R, 0x01);
  set_register(0x5A, NCL_R, 0x00);
  set_register(0x5A, FDL_R, 0x00);

  // Section B - Controls filtering when data is < baseline.
  set_register(0x5A, MHD_F, 0x01);
  set_register(0x5A, NHD_F, 0x01);
  set_register(0x5A, NCL_F, 0xFF);
  set_register(0x5A, FDL_F, 0x02);

  // Section C - Sets touch and release thresholds for each electrode
  set_register(0x5A, ELE0_T, TOU_THRESH);
  set_register(0x5A, ELE0_R, REL_THRESH);

  set_register(0x5A, ELE1_T, TOU_THRESH);
  set_register(0x5A, ELE1_R, REL_THRESH);

  set_register(0x5A, ELE2_T, TOU_THRESH);
  set_register(0x5A, ELE2_R, REL_THRESH);

  set_register(0x5A, ELE3_T, TOU_THRESH);
  set_register(0x5A, ELE3_R, REL_THRESH);

  set_register(0x5A, ELE4_T, TOU_THRESH);
  set_register(0x5A, ELE4_R, REL_THRESH);

  set_register(0x5A, ELE5_T, TOU_THRESH);
  set_register(0x5A, ELE5_R, REL_THRESH);

  set_register(0x5A, ELE6_T, TOU_THRESH);
  set_register(0x5A, ELE6_R, REL_THRESH);

  set_register(0x5A, ELE7_T, TOU_THRESH);
  set_register(0x5A, ELE7_R, REL_THRESH);

  set_register(0x5A, ELE8_T, TOU_THRESH);
  set_register(0x5A, ELE8_R, REL_THRESH);

  set_register(0x5A, ELE9_T, TOU_THRESH);
  set_register(0x5A, ELE9_R, REL_THRESH);

  set_register(0x5A, ELE10_T, TOU_THRESH);
  set_register(0x5A, ELE10_R, REL_THRESH);

  set_register(0x5A, ELE11_T, TOU_THRESH);
  set_register(0x5A, ELE11_R, REL_THRESH);

  // Section D
  // Set the Filter Configuration
  // Set ESI2
  set_register(0x5A, FIL_CFG, 0x04);

  // Section E
  // Electrode Configuration
  // Set ELE_CFG to 0x00 to return to standby mode
  set_register(0x5A, ELE_CFG, 0x0C);  // Enables all 12 Electrodes


  // Section F
  // Enable Auto Config and auto Reconfig
  /*
  set_register(0x5A, ATO_CFG0, 0x0B);
  set_register(0x5A, ATO_CFGU, 0xC9);  // USL = (Vdd-0.7)/vdd*256 = 0xC9 @3.3V   set_register(0x5A, ATO_CFGL, 0x82);  // LSL = 0.65*USL = 0x82 @3.3V
  set_register(0x5A, ATO_CFGT, 0xB5);  // Target = 0.9*USL = 0xB5 @3.3V
  */
  set_register(0x5A, ELE_CFG, 0x0C);

}


void set_register(uint8_t address, uint8_t reg, uint8_t val){

    chThdSleepMilliseconds(1);
    /*
    if (chThdShouldTerminate()) {
        i2cStop(&I2CD1);
        return;
    }
    */
    txbuf[0] = reg;
    txbuf[1] = val;
    msg_t status = RDY_OK;
    i2cAcquireBus(&I2CD1);
    msg_t msg = i2c_lld_master_transmit_timeout(&I2CD1, 0x5A, txbuf, 2, rxbuf, 0, TIME_INFINITE);
    i2cReleaseBus(&I2CD1);

    if (msg != RDY_OK) {
        LogTextMessage("error %i", i2cGetErrors(&I2CD1));
        return;
    }
    else if (msg != RDY_OK) {
        LogTextMessage("OK %i", i2cGetErrors(&I2CD1));

    }

}

uint8_t checkInterrupt(void){
  return (palReadPad(GPIOB,1)<<27);
}