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LibrePilot/flight/pios/common/pios_ms4525do.c

84 lines
2.4 KiB
C

/**
******************************************************************************
* @addtogroup PIOS PIOS Core hardware abstraction layer
* @{
* @addtogroup PIOS_MS4525DO MS4525DO Functions
* @brief Hardware functions to deal with the PixHawk Airspeed Sensor based on MS4525DO
* @{
*
* @file pios_ms4525do.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2014.
* @brief PixHawk MS4525DO 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_MS4525DO
/* Local Defs and Variables */
static int8_t PIOS_MS4525DO_ReadI2C(uint8_t *buffer, uint8_t len)
{
const struct pios_i2c_txn txn_list[] = {
{
.info = __func__,
.addr = MS4525DO_I2C_ADDR,
.rw = PIOS_I2C_TXN_READ,
.len = len,
.buf = buffer,
}
};
return PIOS_I2C_Transfer(PIOS_I2C_MS4525DO_ADAPTER, txn_list, NELEMENTS(txn_list));
}
// values has to ba an arrray with two elements
// values stay untouched on error
int8_t PIOS_MS4525DO_Read(uint16_t *values)
{
uint8_t data[4];
int8_t retVal = PIOS_MS4525DO_ReadI2C(data, sizeof(data));
uint8_t status = data[0] & 0xC0;
if (status == 0x80) {
/* stale data */
return -5;
} else if (status == 0xC0) {
/* device probably broken */
return -6;
}
/* differential pressure */
values[0] = (data[0] << 8);
values[0] += data[1];
/* temperature */
values[1] = (data[2] << 8);
values[1] += data[3];
values[1] = (values[1] >> 5);
return retVal;
}
#endif /* PIOS_INCLUDE_MS4525DO */