File content as of revision 4:b32cf4ef45c5:

/******************************************************************************
 * Includes
 *****************************************************************************/

#include "mbed.h"
#include "mbed_debug.h"

#include "AR1021.h"

/******************************************************************************
 * Defines and typedefs
 *****************************************************************************/

#define AR1021_REG_TOUCH_THRESHOLD        (0x02)
#define AR1021_REG_SENS_FILTER            (0x03)
#define AR1021_REG_SAMPLING_FAST          (0x04)
#define AR1021_REG_SAMPLING_SLOW          (0x05)
#define AR1021_REG_ACC_FILTER_FAST        (0x06)
#define AR1021_REG_ACC_FILTER_SLOW        (0x07)
#define AR1021_REG_SPEED_THRESHOLD        (0x08)
#define AR1021_REG_SLEEP_DELAY            (0x0A)
#define AR1021_REG_PEN_UP_DELAY           (0x0B)
#define AR1021_REG_TOUCH_MODE             (0x0C)
#define AR1021_REG_TOUCH_OPTIONS          (0x0D)
#define AR1021_REG_CALIB_INSETS           (0x0E)
#define AR1021_REG_PEN_STATE_REPORT_DELAY (0x0F)
#define AR1021_REG_TOUCH_REPORT_DELAY     (0x11)


#define AR1021_CMD_GET_VERSION                 (0x10)
#define AR1021_CMD_ENABLE_TOUCH                (0x12)
#define AR1021_CMD_DISABLE_TOUCH               (0x13)
#define AR1021_CMD_CALIBRATE_MODE              (0x14)
#define AR1021_CMD_REGISTER_READ               (0x20)
#define AR1021_CMD_REGISTER_WRITE              (0x21)
#define AR1021_CMD_REGISTER_START_ADDR_REQUEST (0x22)
#define AR1021_CMD_REGISTER_WRITE_TO_EEPROM    (0x23)
#define AR1021_CMD_EEPROM_READ                 (0x28)
#define AR1021_CMD_EEPROM_WRITE                (0x29)
#define AR1021_CMD_EEPROM_WRITE_TO_REGISTERS   (0x2B)

#define AR1021_RESP_STAT_OK           (0x00)
#define AR1021_RESP_STAT_CMD_UNREC    (0x01)
#define AR1021_RESP_STAT_HDR_UNREC    (0x03)
#define AR1021_RESP_STAT_TIMEOUT      (0x04)
#define AR1021_RESP_STAT_CANCEL_CALIB (0xFC)


#define AR1021_ERR_NO_HDR      (-1000)
#define AR1021_ERR_INV_LEN     (-1001)
#define AR1021_ERR_INV_RESP    (-1002)
#define AR1021_ERR_INV_RESPLEN (-1003)
#define AR1021_ERR_TIMEOUT     (-1004)

// bit 7 is always 1 and bit 0 defines pen up or down
#define AR1021_PEN_MASK (0x81)

#define AR1021_NUM_CALIB_POINTS (4)

AR1021::AR1021(PinName mosi, PinName miso, PinName sck, PinName cs, PinName siq) :
_spi(mosi, miso, sck), _cs(cs), _siq(siq), _siqIrq(siq)
{
    _cs = 1; // active low

    _spi.format(8, 1);
    _spi.frequency(500000);

    // default calibration inset is 25 -> (25/2 = 12.5%)
    _inset = 25;

    // make sure _calibPoint has an invalid value to begin with
    // correct value is set in calibrateStart()
    _calibPoint = AR1021_NUM_CALIB_POINTS+1;

    _x = 0;
    _y = 0;
    _pen = 0;

    _initialized = false;
}


bool AR1021::read(touchCoordinate_t &coord) {

    if (!_initialized) return false;

    coord.x = _x * _width/4095;
    coord.y = _y * _height/4095;
    coord.z = _pen;

    return true;
}


bool AR1021::init(uint16_t width, uint16_t height) {
    int result = 0;
    bool ok = false;
    int attempts = 0;

    _width = width;
    _height = height;

    while (1) {

        do {
            // disable touch
            result = cmd(AR1021_CMD_DISABLE_TOUCH, NULL, 0, NULL, 0);
            if (result != 0) {
                debug("disable touch failed (%d)\n", result);
                break;
            }

            char regOffset = 0;
            int regOffLen = 1;
            result = cmd(AR1021_CMD_REGISTER_START_ADDR_REQUEST, NULL, 0,
                    &regOffset, &regOffLen);
            if (result != 0) {
                debug("register offset request failed (%d)\n", result);
                break;
            }

            // enable calibrated coordinates
            //                  high, low address,                        len,  value
            char toptions[4] = {0x00, AR1021_REG_TOUCH_OPTIONS+regOffset, 0x01, 0x01};
            result = cmd(AR1021_CMD_REGISTER_WRITE, toptions, 4, NULL, 0);
            if (result != 0) {
                debug("register write request failed (%d)\n", result);
                break;
            }

            // save registers to eeprom
            result = cmd(AR1021_CMD_REGISTER_WRITE_TO_EEPROM, NULL, 0, NULL, 0);
            if (result != 0) {
                debug("register write to eeprom failed (%d)\n", result);
                break;
            }

            // enable touch
            result = cmd(AR1021_CMD_ENABLE_TOUCH, NULL, 0, NULL, 0);
            if (result != 0) {
                debug("enable touch failed (%d)\n", result);
                break;
            }

            _siqIrq.rise(this, &AR1021::readTouchIrq);

            _initialized = true;
            ok = true;

        } while(0);

        if (ok) break;

        // try to run the initialize sequence at most 2 times
        if(++attempts >= 2) break;
    }


    return ok;
}

bool AR1021::calibrateStart() {
    bool ok = false;
    int result = 0;
    int attempts = 0;

    if (!_initialized) return false;

    _siqIrq.rise(NULL);

    while(1) {

        do {
            // disable touch
            result = cmd(AR1021_CMD_DISABLE_TOUCH, NULL, 0, NULL, 0);
            if (result != 0) {
                debug("disable touch failed (%d)\n", result);
                break;
            }

            char regOffset = 0;
            int regOffLen = 1;
            result = cmd(AR1021_CMD_REGISTER_START_ADDR_REQUEST, NULL, 0,
                    &regOffset, &regOffLen);
            if (result != 0) {
                debug("register offset request failed (%d)\n", result);
                break;
            }

            // set insets
            // enable calibrated coordinates
            //                high, low address,                       len,  value
            char insets[4] = {0x00, AR1021_REG_CALIB_INSETS+regOffset, 0x01, _inset};
            result = cmd(AR1021_CMD_REGISTER_WRITE, insets, 4, NULL, 0);
            if (result != 0) {
                debug("register write request failed (%d)\n", result);
                break;
            }

            // calibration mode
            char calibType = 4;
            result = cmd(AR1021_CMD_CALIBRATE_MODE, &calibType, 1, NULL, 0, false);
            if (result != 0) {
                debug("calibration mode failed (%d)\n", result);
                break;
            }

            _calibPoint = 0;
            ok = true;

        } while(0);

        if (ok) break;

        // try to run the calibrate mode sequence at most 2 times
        if (++attempts >= 2) break;
    }

    return ok;
}

bool AR1021::getNextCalibratePoint(uint16_t* x, uint16_t* y) {

    if (!_initialized) return false;
    if (x == NULL || y == NULL) return false;

    int xInset = (_width * _inset / 100) / 2;
    int yInset = (_height * _inset / 100) / 2;

    switch(_calibPoint) {
    case 0:
        *x = xInset;
        *y = yInset;
        break;
    case 1:
        *x = _width - xInset;
        *y = yInset;
        break;
    case 2:
        *x = _width - xInset;
        *y = _height - yInset;
        break;
    case 3:
        *x = xInset;
        *y = _height - yInset;
        break;
    default:
        return false;
    }

    return true;
}

bool AR1021::waitForCalibratePoint(bool* morePoints, uint32_t timeout) {
    int result = 0;
    bool ret = false;

    if (!_initialized) return false;

    do {
        if (morePoints == NULL || _calibPoint >= AR1021_NUM_CALIB_POINTS) {
            break;
        }

        // wait for response
        result = waitForCalibResponse(timeout);
        if (result != 0) {
            debug("wait for calibration response failed (%d)\n", result);
            break;
        }

        _calibPoint++;
        *morePoints = (_calibPoint < AR1021_NUM_CALIB_POINTS);


        // no more points -> enable touch
        if (!(*morePoints)) {

            // wait for calibration data to be written to eeprom
            // before enabling touch
            result = waitForCalibResponse(timeout);
            if (result != 0) {
                debug("wait for calibration response failed (%d)\n", result);
                break;
            }


            // clear chip-select since calibration is done;
            _cs = 1;

            result = cmd(AR1021_CMD_ENABLE_TOUCH, NULL, 0, NULL, 0);
            if (result != 0) {
                debug("enable touch failed (%d)\n", result);
                break;
            }

            _siqIrq.rise(this, &AR1021::readTouchIrq);
        }

        ret = true;

    } while (0);



    if (!ret) {
        // make sure to set chip-select off in case of an error
        _cs = 1;
        // calibration must restart if an error occurred
        _calibPoint = AR1021_NUM_CALIB_POINTS+1;
    }



    return ret;
}

int AR1021::cmd(char cmd, char* data, int len, char* respBuf, int* respLen,
        bool setCsOff) {

    int ret = 0;

    // command request
    // ---------------
    // 0x55 len cmd data
    // 0x55 = header
    // len = data length + cmd (1)
    // data = data to send

    _cs = 0;

    _spi.write(0x55);
    wait_us(50); // according to data sheet there must be an inter-byte delay of ~50us
    _spi.write(len+1);
    wait_us(50);
    _spi.write(cmd);
    wait_us(50);

    for(int i = 0; i < len; i++) {
        _spi.write(data[i]);
        wait_us(50);
    }


    // wait for response (siq goes high when response is available)
    Timer t;
    t.start();
    while(_siq.read() != 1 && t.read_ms() < 1000);


    // command response
    // ---------------
    // 0x55 len status cmd data
    // 0x55 = header
    // len = number of bytes following the len byte
    // status = status
    // cmd = command ID
    // data = data to receive


    do {

        if (t.read_ms() >= 1000) {
            ret = AR1021_ERR_TIMEOUT;
            break;
        }

        int head = _spi.write(0);
        if (head != 0x55) {
            ret = AR1021_ERR_NO_HDR;
            break;
        }

        wait_us(50);
        int len = _spi.write(0);
        if (len < 2) {
            ret = AR1021_ERR_INV_LEN;
            break;
        }

        wait_us(50);
        int status = _spi.write(0);
        if (status != AR1021_RESP_STAT_OK) {
            ret = -status;
            break;
        }

        wait_us(50);
        int cmdId = _spi.write(0);
        if (cmdId != cmd) {
            ret = AR1021_ERR_INV_RESP;
            break;
        }

        if ( ((len-2) > 0 && respLen  == NULL)
                || ((len-2) > 0 && respLen != NULL && *respLen < (len-2))) {
            ret = AR1021_ERR_INV_RESPLEN;
            break;
        }

        for (int i = 0; i < len-2;i++) {
            wait_us(50);
            respBuf[i] = _spi.write(0);
        }
        if (respLen != NULL) {
            *respLen = len-2;
        }

        // make sure we wait 50us before issuing a new cmd
        wait_us(50);

    } while (0);



    // disable chip-select if setCsOff is true or if an error occurred
    if (setCsOff || ret != 0) {
        _cs = 1;
    }



    return ret;
}

int AR1021::waitForCalibResponse(uint32_t timeout) {
    Timer t;
    int ret = 0;

    t.start();

    // wait for siq
    while (_siq.read() != 1 &&
            (timeout == 0 || (uint32_t)t.read_ms() < (int)timeout));


    do {

        if (timeout >  0 && (uint32_t)t.read_ms() >= timeout) {
            ret = AR1021_ERR_TIMEOUT;
            break;
        }

        int head = _spi.write(0);
        if (head != 0x55) {
            ret = AR1021_ERR_NO_HDR;
            break;
        }

        wait_us(50);
        int len = _spi.write(0);
        if (len != 2) {
            ret = AR1021_ERR_INV_LEN;
            break;
        }

        wait_us(50);
        int status = _spi.write(0);
        if (status != AR1021_RESP_STAT_OK) {
            ret = -status;
            break;
        }

        wait_us(50);
        int cmdId = _spi.write(0);
        if (cmdId != 0x14) {
            ret = AR1021_ERR_INV_RESP;
            break;
        }


        // make sure we wait 50us before issuing a new cmd
        wait_us(50);

    } while (0);


    return ret;
}


void AR1021::readTouchIrq() {
    while(_siq.read() == 1) {

        _cs = 0;

        // touch coordinates are sent in a 5-byte data packet

        int pen = _spi.write(0);
        wait_us(50);

        int xlo = _spi.write(0);
        wait_us(50);

        int xhi = _spi.write(0);
        wait_us(50);

        int ylo = _spi.write(0);
        wait_us(50);

        int yhi = _spi.write(0);
        wait_us(50);

        _cs = 1;


        // pen down
        if ((pen&AR1021_PEN_MASK) == (1<<7|1<<0)) {
            _pen = 1;
        }
        // pen up
        else if ((pen&AR1021_PEN_MASK) == (1<<7)){
            _pen = 0;
        }
        // invalid value
        else {
            continue;
        }

        _x = ((xhi<<7)|xlo);
        _y = ((yhi<<7)|ylo);

    }
}