LibrePilot/flight/pios/common/pios_ms5611.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup PIOS_MS5611 MS5611 Functions
 * @brief Hardware functions to deal with the altitude pressure sensor
 * @{
 *
 * @file       pios_ms5611.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @brief      MS5611 Pressure Sensor Routines
 * @see        The GNU Public License (GPL) Version 3
 *
 ******************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_MS5611


// TODO: Clean this up.  Getting around old constant.
#define PIOS_MS5611_OVERSAMPLING oversampling


/* Glocal Variables */
ConversionTypeTypeDef CurrentRead;

/* Local Variables */
MS5611CalibDataTypeDef CalibData;

/* Straight from the datasheet */
static uint32_t RawTemperature;
static uint32_t RawPressure;
static int64_t Pressure;
static int64_t Temperature;
static int32_t lastConversionStart;
static int32_t PIOS_MS5611_Read(uint8_t address, uint8_t *buffer, uint8_t len);
static int32_t PIOS_MS5611_WriteCommand(uint8_t command);

// Move into proper driver structure with cfg stored
static uint32_t oversampling;
static const struct pios_ms5611_cfg *dev_cfg;
static int32_t i2c_id;


/**
 * Initialise the MS5611 sensor
 */
int32_t ms5611_read_flag;
void PIOS_MS5611_Init(const struct pios_ms5611_cfg *cfg, int32_t i2c_device)
{
    i2c_id  = i2c_device;

    oversampling = cfg->oversampling;
    dev_cfg = cfg; // Store cfg before enabling interrupt

    PIOS_MS5611_WriteCommand(MS5611_RESET);
    PIOS_DELAY_WaitmS(20);

    uint8_t data[2];

    /* Calibration parameters */
    for (int i = 0; i < 6; i++) {
        PIOS_MS5611_Read(MS5611_CALIB_ADDR + i * 2, data, 2);
        CalibData.C[i] = (data[0] << 8) | data[1];
    }
}

/**
 * Start the ADC conversion
 * \param[in] PresOrTemp BMP085_PRES_ADDR or BMP085_TEMP_ADDR
 * \return 0 for success, -1 for failure (conversion completed and not read)
 */
int32_t PIOS_MS5611_StartADC(ConversionTypeTypeDef Type)
{
    /* Start the conversion */
    if (Type == TemperatureConv) {
        while (PIOS_MS5611_WriteCommand(MS5611_TEMP_ADDR + oversampling) != 0) {
            continue;
        }
    } else if (Type == PressureConv) {
        while (PIOS_MS5611_WriteCommand(MS5611_PRES_ADDR + oversampling) != 0) {
            continue;
        }
    }
    lastConversionStart = PIOS_DELAY_GetRaw();
    CurrentRead = Type;

    return 0;
}

/**
 * @brief Return the delay for the current osr
 */
int32_t PIOS_MS5611_GetDelay()
{
    switch (oversampling) {
    case MS5611_OSR_256:
        return 1;

    case MS5611_OSR_512:
        return 2;

    case MS5611_OSR_1024:
        return 3;

    case MS5611_OSR_2048:
        return 5;

    case MS5611_OSR_4096:
        return 10;

    default:
        break;
    }
    return 10;
}

/**
 * @brief Return the delay for the current osr in uS
 */
uint32_t PIOS_MS5611_GetDelayUs()
{
    switch (oversampling) {
    case MS5611_OSR_256:
        return 600;

    case MS5611_OSR_512:
        return 1170;

    case MS5611_OSR_1024:
        return 2280;

    case MS5611_OSR_2048:
        return 4540;

    case MS5611_OSR_4096:
        return 9040;

    default:
        break;
    }
    return 10;
}

/**
 * Read the ADC conversion value (once ADC conversion has completed)
 * \param[in] PresOrTemp BMP085_PRES_ADDR or BMP085_TEMP_ADDR
 * \return 0 if successfully read the ADC, -1 if failed
 */
int32_t PIOS_MS5611_ReadADC(void)
{
    uint8_t Data[3];

    Data[0] = 0;
    Data[1] = 0;
    Data[2] = 0;

    while (PIOS_MS5611_GetDelayUs() > PIOS_DELAY_DiffuS(lastConversionStart)) {
        vTaskDelay(0);
    }
    static int64_t deltaTemp;

    /* Read and store the 16bit result */
    if (CurrentRead == TemperatureConv) {
        /* Read the temperature conversion */
        if (PIOS_MS5611_Read(MS5611_ADC_READ, Data, 3) != 0) {
            return -1;
        }

        RawTemperature = (Data[0] << 16) | (Data[1] << 8) | Data[2];

        deltaTemp = ((int32_t)RawTemperature) - (CalibData.C[4] << 8);
        Temperature    = 2000l + ((deltaTemp * CalibData.C[5]) >> 23);
    } else {
        int64_t Offset;
        int64_t Sens;

        /* Read the pressure conversion */
        if (PIOS_MS5611_Read(MS5611_ADC_READ, Data, 3) != 0) {
            return -1;
        }
        RawPressure = ((Data[0] << 16) | (Data[1] << 8) | Data[2]);

        Offset   = (((int64_t)CalibData.C[1]) << 16) + ((((int64_t)CalibData.C[3]) * deltaTemp) >> 7);
        Sens     = ((int64_t)CalibData.C[0]) << 15;
        Sens     = Sens + ((((int64_t)CalibData.C[2]) * deltaTemp) >> 8);

        Pressure = (((((int64_t)RawPressure) * Sens) >> 21) - Offset) >> 15;
    }
    return 0;
}

/**
 * Return the most recently computed temperature in kPa
 */
float PIOS_MS5611_GetTemperature(void)
{
    return ((float)Temperature) / 100.0f;
}

/**
 * Return the most recently computed pressure in kPa
 */
float PIOS_MS5611_GetPressure(void)
{
    return ((float)Pressure) / 1000.0f;
}

/**
 * Reads one or more bytes into a buffer
 * \param[in] the command indicating the address to read
 * \param[out] buffer destination buffer
 * \param[in] len number of bytes which should be read
 * \return 0 if operation was successful
 * \return -1 if error during I2C transfer
 */
int32_t PIOS_MS5611_Read(uint8_t address, uint8_t *buffer, uint8_t len)
{
    const struct pios_i2c_txn txn_list[] = {
        {
            .info = __func__,
            .addr = MS5611_I2C_ADDR,
            .rw   = PIOS_I2C_TXN_WRITE,
            .len  = 1,
            .buf  = &address,
        }
        ,
        {
            .info = __func__,
            .addr = MS5611_I2C_ADDR,
            .rw   = PIOS_I2C_TXN_READ,
            .len  = len,
            .buf  = buffer,
        }
    };

    return PIOS_I2C_Transfer(i2c_id, txn_list, NELEMENTS(txn_list));
}

/**
 * Writes one or more bytes to the MS5611
 * \param[in] address Register address
 * \param[in] buffer source buffer
 * \return 0 if operation was successful
 * \return -1 if error during I2C transfer
 */
int32_t PIOS_MS5611_WriteCommand(uint8_t command)
{
    const struct pios_i2c_txn txn_list[] = {
        {
            .info = __func__,
            .addr = MS5611_I2C_ADDR,
            .rw   = PIOS_I2C_TXN_WRITE,
            .len  = 1,
            .buf  = &command,
        }
        ,
    };

    return PIOS_I2C_Transfer(i2c_id, txn_list, NELEMENTS(txn_list));
}

/**
 * @brief Run self-test operation.
 * \return 0 if self-test succeed, -1 if failed
 */
int32_t PIOS_MS5611_Test()
{
    // TODO: Is there a better way to test this than just checking that pressure/temperature has changed?
    int32_t cur_value = 0;

    cur_value = Temperature;
    PIOS_MS5611_StartADC(TemperatureConv);
    PIOS_DELAY_WaitmS(5);
    PIOS_MS5611_ReadADC();
    if (cur_value == Temperature) {
        return -1;
    }

    cur_value = Pressure;
    PIOS_MS5611_StartADC(PressureConv);
    PIOS_DELAY_WaitmS(26);
    PIOS_MS5611_ReadADC();
    if (cur_value == Pressure) {
        return -1;
    }

    return 0;
}

#endif /* PIOS_INCLUDE_MS5611 */

/**
 * @}
 * @}
 */