motor/Common/spi/Compass_RM3100.c

#include "Compass_RM3100.h"
#include <stdio.h>

#define RM3100_POLL_REG 0x00

#define RM3100_CMM_REG 0x01

#define RM3100_CCX1_REG 0x04
#define RM3100_CCX0_REG 0x05
#define RM3100_CCY1_REG 0x06
#define RM3100_CCY0_REG 0x07
#define RM3100_CCZ1_REG 0x08
#define RM3100_CCZ0_REG 0x09

#define RM3100_TMRC_REG 0x0B

#define RM3100_MX2_REG 0x24
#define RM3100_MX1_REG 0x25
#define RM3100_MX0_REG 0x26
#define RM3100_MY2_REG 0x27
#define RM3100_MY1_REG 0x28
#define RM3100_MY0_REG 0x29
#define RM3100_MZ2_REG 0x2A
#define RM3100_MZ1_REG 0x2B
#define RM3100_MZ0_REG 0x2C

#define RM3100_BIST_REG 0x33
#define RM3100_STATUS_REG 0x34
#define RM3100_HSHAKE_REG 0x34
#define RM3100_REVID_REG 0x36

#define CCP0 0xC8 // Cycle Count values
#define CCP1 0x00
#define CCP0_DEFAULT 0xC8 // Default Cycle Count values (used as a whoami check)
#define CCP1_DEFAULT 0x00
#define GAIN_CC50 20.0f // LSB/uT
#define GAIN_CC100 38.0f
#define GAIN_CC200 75.0f
#define UTESLA_TO_MGAUSS 10.0f // uT to mGauss conversion

#define TMRC 0x94 // Update rate 150Hz
#define CMM 0x71  // read 3 axes and set data ready if 3 axes are ready

static bool read_registers(SPI_DEV_t *dev, uint8_t reg, uint8_t *buf,
                           uint32_t size)
{
    SPI_DEV_select(dev);
    bool rslt = SPI_DEV_read_registers(dev, reg, buf, size);
    SPI_DEV_unselect(dev);
    return rslt;
}

static bool write_register(SPI_DEV_t *dev, uint8_t reg, uint8_t val)
{
    SPI_DEV_select(dev);
    bool rslt = SPI_DEV_write_register(dev, reg, val);
    SPI_DEV_unselect(dev);
    return rslt;
}

bool Compass_RM3100_init(Compass_RM3100_t *cps, const char *name, SPI_DEV_t *dev, GPIO_EXIT_t *drdy)
{
    int i;

    cps->name = name;
    cps->dev = dev;
    cps->drdy = drdy;
    cps->_scaler = 1.0;
    cps->success = false;

    SPI_DEV_begin(dev, -1);

    // read has high bit set for SPI
    SPI_DEV_set_read_flag(dev, 0x80);

    // high retries for init
    //dev->set_retries(10);

    // use default cycle count values as a whoami test
    uint8_t ccx0;
    uint8_t ccx1;
    uint8_t ccy0;
    uint8_t ccy1;
    uint8_t ccz0;
    uint8_t ccz1;
    if (!read_registers(dev, RM3100_CCX1_REG, &ccx1, 1) ||
        !read_registers(dev, RM3100_CCX0_REG, &ccx0, 1) ||
        !read_registers(dev, RM3100_CCY1_REG, &ccy1, 1) ||
        !read_registers(dev, RM3100_CCY0_REG, &ccy0, 1) ||
        !read_registers(dev, RM3100_CCZ1_REG, &ccz1, 1) ||
        !read_registers(dev, RM3100_CCZ0_REG, &ccz0, 1) ||
        ccx1 != CCP1_DEFAULT || ccx0 != CCP0_DEFAULT ||
        ccy1 != CCP1_DEFAULT || ccy0 != CCP0_DEFAULT ||
        ccz1 != CCP1_DEFAULT || ccz0 != CCP0_DEFAULT)
    {
        // couldn't read one of the cycle count registers or didn't recognize the default cycle count values
        SPI_DEV_end(dev);
        return false;
    }

    write_register(dev, RM3100_TMRC_REG, TMRC); // CMM data rate
    write_register(dev, RM3100_CMM_REG, CMM);   // CMM configuration
    write_register(dev, RM3100_CCX1_REG, CCP1); // cycle count x
    write_register(dev, RM3100_CCX0_REG, CCP0); // cycle count x
    write_register(dev, RM3100_CCY1_REG, CCP1); // cycle count y
    write_register(dev, RM3100_CCY0_REG, CCP0); // cycle count y
    write_register(dev, RM3100_CCZ1_REG, CCP1); // cycle count z
    write_register(dev, RM3100_CCZ0_REG, CCP0); // cycle count z

    cps->_scaler = (1 / GAIN_CC200) * UTESLA_TO_MGAUSS; // has to be changed if using a different cycle count

    // lower retries for run
    //dev->set_retries(3);

    //Built-in Test
    write_register(dev, RM3100_BIST_REG, 0b10001010); // test
    for (i = 0; i < 10; ++i)
    {
        uint8_t status;
        if (!read_registers(cps->dev, RM3100_STATUS_REG, (uint8_t *)&status, 1))
        {
            break;
        }
        if ((status & 0x80))
        {
            if (read_registers(dev, RM3100_BIST_REG, &status, 1))
            {
                if ((status & 0b01110000) == 0b01110000)
                {
                    write_register(dev, RM3100_BIST_REG, 0b00000000); // done
                    cps->success = true;
                }
            }
            break;
        }
        osDelay(10);
    }

    SPI_DEV_end(dev);

    printf("RM3100: Foundas compass.\n");

    return cps->success;
}

void Compass_RM3100_update(Compass_RM3100_t *cps)
{
    struct PACKED
    {
        uint8_t magx_2;
        uint8_t magx_1;
        uint8_t magx_0;
        uint8_t magy_2;
        uint8_t magy_1;
        uint8_t magy_0;
        uint8_t magz_2;
        uint8_t magz_1;
        uint8_t magz_0;
    } data;

    int32_t magx = 0;
    int32_t magy = 0;
    int32_t magz = 0;

    if (cps->success && SPI_DEV_begin(cps->dev, 0))
    {
        // check data ready on 3 axis
        uint8_t status;
        if (!read_registers(cps->dev, RM3100_STATUS_REG, (uint8_t *)&status, 1))
        {
            cps->bad_cnt++;
            goto check_registers;
        }

        if (!(status & 0x80))
        {
            // data not available yet
            cps->nrdy_cnt++;
            goto check_registers;
        }

        if (!read_registers(cps->dev, RM3100_MX2_REG, (uint8_t *)&data, sizeof(data)))
        {
            cps->bad_cnt++;
            goto check_registers;
        }

        // the 24 bits of data for each axis are in 2s complement representation
        // each byte is shifted to its position in a 24-bit unsigned integer and from 8 more bits to be left-aligned in a 32-bit integer
        magx = ((uint32_t)data.magx_2 << 24) | ((uint32_t)data.magx_1 << 16) | ((uint32_t)data.magx_0 << 8);
        magy = ((uint32_t)data.magy_2 << 24) | ((uint32_t)data.magy_1 << 16) | ((uint32_t)data.magy_0 << 8);
        magz = ((uint32_t)data.magz_2 << 24) | ((uint32_t)data.magz_1 << 16) | ((uint32_t)data.magz_0 << 8);

        // right-shift signed integer back to get correct measurement value
        magx >>= 8;
        magy >>= 8;
        magz >>= 8;

        // apply scaler and store in field vector
        cps->magx = magx * cps->_scaler;
        cps->magy = magy * cps->_scaler;
        cps->magz = magz * cps->_scaler;

        cps->good_cnt++;
        cps->seq++;

    check_registers:
        SPI_DEV_end(cps->dev);
    }
}

void Compass_RM3100_monitor(Compass_RM3100_t *cps)
{
    cps->good_pps = cps->good_cnt;
    cps->bad_pps = cps->bad_cnt;
    cps->nrdy_pps = cps->nrdy_cnt;
    cps->nrdy_cnt = 0;
    cps->good_cnt = 0;
    cps->bad_cnt = 0;
}

void Compass_RM3100_loop(Compass_RM3100_t *cps)
{
    while (true)
    {
        cps->drdy->task = xTaskGetCurrentTaskHandle();
        ulTaskNotifyTake(pdTRUE, 50);
        Compass_RM3100_update(cps);
    }
}