LibrePilot/flight/pios/common/pios_etasv3.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup PIOS_ETASV3 ETASV3 Functions
 * @brief Hardware functions to deal with the Eagle Tree Airspeed MicroSensor V3
 * @{
 *
 * @file       pios_etasv3.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @brief      ETASV3 Airspeed Sensor Driver
 * @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_ETASV3

static bool PIOS_ETASV3_Read(uint8_t *buffer, uint8_t len)
{
    const struct pios_i2c_txn txn_list[] = {
        {
            .info = __func__,
            .addr = ETASV3_I2C_ADDR,
            .rw   = PIOS_I2C_TXN_READ,
            .len  = len,
            .buf  = buffer,
        }
    };

    return PIOS_I2C_Transfer(PIOS_I2C_ETASV3_ADAPTER, txn_list, NELEMENTS(txn_list));
}

int16_t PIOS_ETASV3_ReadAirspeed(void)
{
    uint8_t airspeed_raw[2];

    if (PIOS_ETASV3_Read(airspeed_raw, sizeof(airspeed_raw)) != 0) {
        /* Failed to read airspeed */
        return -1;
    }

    return airspeed_raw[0] | (airspeed_raw[1] << 8);
}

#endif /* PIOS_INCLUDE_ETASV3 */