axoloti I2C MPR121

// 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  0x0F
#define REL_THRESH  0x0A

// I2C R/W Address of the MPR121. ADD is unconnected = 0x5A.
#define MPR121_R 0xB5
#define MPR121_W 0xB4

uint8_t rxbuf[8];
uint8_t txbuf[8];

systime_t tmo = MS2ST(4);

void setup(void){
    txbuf[0] = ELE_CFG;
    txbuf[1] = 0x00;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 2, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    // Section A - Controls filtering when data is > baseline.
    txbuf[0] = MHD_R;
    txbuf[1] = 0x01;
    txbuf[2] = NHD_R;
    txbuf[3] = 0x01;
    txbuf[4] = NCL_R;
    txbuf[5] = 0x00;
    txbuf[6] = FDL_R;
    txbuf[7] = 0x00;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 8, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    // Section B - Controls filtering when data is < baseline.
    txbuf[0] = MHD_F;
    txbuf[1] = 0x01;
    txbuf[2] = NHD_F;
    txbuf[3] = 0x01;
    txbuf[4] = NCL_F;
    txbuf[5] = 0xFF;
    txbuf[6] = FDL_F;
    txbuf[7] = 0x02;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 8, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    // Section C - Sets touch and release thresholds for each electrode
    txbuf[0] = ELE0_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE0_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE1_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE1_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE2_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE2_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE3_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE3_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE4_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE4_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE5_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE5_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE6_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE6_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE7_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE7_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE8_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE8_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE9_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE9_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE10_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE10_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    txbuf[0] = ELE11_T;
    txbuf[1] = TOU_THRESH;
    txbuf[2] = ELE11_R;
    txbuf[3] = REL_THRESH;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 4, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    // Section D
    // Set the Filter Configuration
    // Set ESI2
    txbuf[0] = FIL_CFG;
    txbuf[1] = 0x04;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 2, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    // Section E
    // Electrode Configuration
    // Set ELE_CFG to 0x00 to return to standby mode
    txbuf[0] = ELE_CFG;
    txbuf[1] = 0x0C;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 2, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);

    // Section F
    // Enable Auto Config and auto Reconfig


    txbuf[0] = ATO_CFG0;
    txbuf[1] = 0x0B;
    txbuf[2] = ATO_CFGU;        // USL = (Vdd-0.7)/vdd*256 = 0xC9 @3.3V   set_register(0x5A, ATO_CFGL, 0x82);  // LSL = 0.65*USL = 0x82 @3.3V
    txbuf[3] = 0xC9;
    txbuf[4] = ATO_CFGT;        // Target = 0.9*USL = 0xB5 @3.3V
    txbuf[5] = 0xB5;

    i2cAcquireBus(&I2CD1);
    i2cMasterTransmitTimeout(&I2CD1, MPR121_W, txbuf, 6, rxbuf, 0, tmo);
    i2cReleaseBus(&I2CD1);
}

void loop(void){
    chThdSleepMilliseconds(10);
    i2cAcquireBus(&I2CD1);
    i2cMasterReceiveTimeout(&I2CD1, MPR121_R, rxbuf, 2, tmo);
    i2cReleaseBus(&I2CD1);
}