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
 */

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

#include "pios.h"

#if defined(PIOS_INCLUDE_MS5611)

/* 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 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;
	}

	CurrentRead = Type;
	
	return 0;
}

/**
 * @brief Return the delay for the current osr
 */
int32_t PIOS_MS5611_GetDelay() {
	switch(oversampling) {
		case MS5611_OSR_256:
			return 2;
		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;
}
/**
* 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;
	
	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

/**
 * @}
 * @}
 */