From ae0a1c842a4e709b98440c561ece7c4fda19e86c Mon Sep 17 00:00:00 2001 From: Kevin Townsend Date: Wed, 20 Jun 2012 04:02:41 +0200 Subject: [PATCH] First commit --- drivers/sensors/mpl115a2/mpl115a2.c | 185 ++++++++++++++++++++++++++++ drivers/sensors/mpl115a2/mpl115a2.h | 77 ++++++++++++ 2 files changed, 262 insertions(+) create mode 100644 drivers/sensors/mpl115a2/mpl115a2.c create mode 100644 drivers/sensors/mpl115a2/mpl115a2.h diff --git a/drivers/sensors/mpl115a2/mpl115a2.c b/drivers/sensors/mpl115a2/mpl115a2.c new file mode 100644 index 0000000..c815f14 --- /dev/null +++ b/drivers/sensors/mpl115a2/mpl115a2.c @@ -0,0 +1,185 @@ +/**************************************************************************/ +/*! + @file mpl115a2.c + @author K. Townsend (microBuilder.eu) + + @brief Drivers for the Freescale MPL115A2 I2C Digital Barometer + + @section DESCRIPTION + + The MPL115A2 is an I2C absolute pressure sensor, employing a MEMS + pressure sensor with a conditioning IC to provide accurate pressure + measurements from 50 to 115 kPa. + + @section LICENSE + + Software License Agreement (BSD License) + + Copyright (c) 2012, K. Townsend + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are met: + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + 3. Neither the name of the copyright holders nor the + names of its contributors may be used to endorse or promote products + derived from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY + EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY + DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ +/**************************************************************************/ +#include "mpl115a2.h" +#include "core/systick/systick.h" + +extern volatile uint8_t I2CMasterBuffer[I2C_BUFSIZE]; +extern volatile uint8_t I2CSlaveBuffer[I2C_BUFSIZE]; +extern volatile uint32_t I2CReadLength, I2CWriteLength; + +static float _mpl115a2_a0; +static float _mpl115a2_b1; +static float _mpl115a2_b2; +static float _mpl115a2_c12; + +static bool _mpl115a2Initialised = false; + +/**************************************************************************/ +/*! + @brief Reads an 8 bit value over I2C +*/ +/**************************************************************************/ +mpl115a2Error_t mpl115a2ReadPressureTemp(uint16_t *pressure, uint16_t *temp) +{ + // Clear write buffers + uint32_t i; + for ( i = 0; i < I2C_BUFSIZE; i++ ) + { + I2CMasterBuffer[i] = 0x00; + I2CSlaveBuffer[i] = 0x00; + } + + I2CWriteLength = 3; + I2CReadLength = 1; + I2CMasterBuffer[0] = MPL115A2_ADDRESS; + I2CMasterBuffer[1] = MPL115A2_REGISTER_STARTCONVERSION; + I2CMasterBuffer[2] = 0x00; // Why is this necessary to get results? + i2cEngine(); + + // Wait a bit for the conversion to complete (3ms max) + systickDelay(5); + + I2CWriteLength = 2; + I2CReadLength = 4; + I2CMasterBuffer[0] = MPL115A2_ADDRESS; + I2CMasterBuffer[1] = MPL115A2_REGISTER_PRESSURE_MSB; + I2CMasterBuffer[2] = MPL115A2_ADDRESS | MPL115A2_READBIT; + i2cEngine(); + + // Shift values to create properly formed integers + *pressure = ((I2CSlaveBuffer[0] << 8) | (I2CSlaveBuffer[1])) >> 6; + *temp = ((I2CSlaveBuffer[2] << 8) | (I2CSlaveBuffer[3])) >> 6; + + return MPL115A2_ERROR_OK; +} + +/**************************************************************************/ +/*! + @brief Reads the factory-set coefficients +*/ +/**************************************************************************/ +mpl115a2Error_t mpl115a2ReadCoefficients(void) +{ + int16_t a0coeff; + int16_t b1coeff; + int16_t b2coeff; + int16_t c12coeff; + + // Clear write buffers + uint32_t i; + for ( i = 0; i < I2C_BUFSIZE; i++ ) + { + I2CMasterBuffer[i] = 0x00; + I2CSlaveBuffer[i] = 0x00; + } + + I2CWriteLength = 2; + I2CReadLength = 8; + I2CMasterBuffer[0] = MPL115A2_ADDRESS; + I2CMasterBuffer[1] = MPL115A2_REGISTER_A0_COEFF_MSB; + I2CMasterBuffer[2] = MPL115A2_ADDRESS | MPL115A2_READBIT; + i2cEngine(); + + a0coeff = (I2CSlaveBuffer[0] << 8 ) | I2CSlaveBuffer[1]; + b1coeff = (I2CSlaveBuffer[2] << 8 ) | I2CSlaveBuffer[3]; + b2coeff = (I2CSlaveBuffer[4] << 8 ) | I2CSlaveBuffer[5]; + c12coeff = ((I2CSlaveBuffer[6] << 8 ) | I2CSlaveBuffer[7]) >> 2; + + _mpl115a2_a0 = (float)a0coeff / 8; + _mpl115a2_b1 = (float)b1coeff / 8192; + _mpl115a2_b2 = (float)b2coeff / 16384; + _mpl115a2_c12 = (float)c12coeff / 4194304; + + return MPL115A2_ERROR_OK; +} + +/**************************************************************************/ +/*! + @brief Initialises the I2C block +*/ +/**************************************************************************/ +mpl115a2Error_t mpl115a2Init(void) +{ + mpl115a2Error_t error = MPL115A2_ERROR_OK; + + // Initialise I2C + if (i2cInit(I2CMASTER) == false) + { + return MPL115A2_ERROR_I2CINIT; /* Fatal error */ + } + + // Coefficients only need to be read once + mpl115a2ReadCoefficients(); + + _mpl115a2Initialised = true; + return error; +} + +/**************************************************************************/ +/*! + @brief Gets the compensated pressure level in kPa +*/ +/**************************************************************************/ +mpl115a2Error_t mpl115a2GetPressure(float *pressure) +{ + uint16_t Padc, Tadc; + float Pcomp; + + mpl115a2Error_t error = MPL115A2_ERROR_OK; + + // Make sure the coefficients have been read, etc. + if (!_mpl115a2Initialised) mpl115a2Init(); + + // Get raw pressure and temperature settings + error = mpl115a2ReadPressureTemp(&Padc, &Tadc); + if (error) return error; + + // See datasheet p.6 for evaluation sequence + Pcomp = _mpl115a2_a0 + (_mpl115a2_b1 + _mpl115a2_c12 * Tadc ) * Padc + _mpl115a2_b2 * Tadc; + + // Return pressure as floating point value + *pressure = ((65.0 / 1023.0)*(float)Pcomp) + 50; + + return error; +} diff --git a/drivers/sensors/mpl115a2/mpl115a2.h b/drivers/sensors/mpl115a2/mpl115a2.h new file mode 100644 index 0000000..354a3a4 --- /dev/null +++ b/drivers/sensors/mpl115a2/mpl115a2.h @@ -0,0 +1,77 @@ +/**************************************************************************/ +/*! + @file mpl115a2.h + @author K. Townsend (microBuilder.eu) + + @section LICENSE + + Software License Agreement (BSD License) + + Copyright (c) 2012, K. Townsend + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are met: + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + 3. Neither the name of the copyright holders nor the + names of its contributors may be used to endorse or promote products + derived from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY + EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY + DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ +/**************************************************************************/ + +#ifndef _MPL115A2_H_ +#define _MPL115A2_H_ + +#include "projectconfig.h" +#include "core/i2c/i2c.h" + +#define MPL115A2_ADDRESS (0xC0) // 1100 000 shifted left 1 bit = 0xC0 +#define MPL115A2_READBIT (0x01) + +enum +{ + MPL115A2_REGISTER_PRESSURE_MSB = 0x00, + MPL115A2_REGISTER_PRESSURE_LSB = 0x01, + MPL115A2_REGISTER_TEMP_MSB = 0x02, + MPL115A2_REGISTER_TEMP_LSB = 0x03, + MPL115A2_REGISTER_A0_COEFF_MSB = 0x04, + MPL115A2_REGISTER_A0_COEFF_LSB = 0x05, + MPL115A2_REGISTER_B1_COEFF_MSB = 0x06, + MPL115A2_REGISTER_B1_COEFF_LSB = 0x07, + MPL115A2_REGISTER_B2_COEFF_MSB = 0x08, + MPL115A2_REGISTER_B2_COEFF_LSB = 0x09, + MPL115A2_REGISTER_C12_COEFF_MSB = 0x0A, + MPL115A2_REGISTER_C12_COEFF_LSB = 0x0B, + MPL115A2_REGISTER_STARTCONVERSION = 0x12 +}; + +typedef enum +{ + MPL115A2_ERROR_OK = 0, // Everything executed normally + MPL115A2_ERROR_I2CINIT, // Unable to initialise I2C + MPL115A2_ERROR_I2CBUSY, // I2C already in use + MPL115A2_ERROR_LAST +} +mpl115a2Error_t; + +mpl115a2Error_t mpl115a2Init(void); +mpl115a2Error_t mpl115a2GetPressure(float *pressure); + +#endif + + -- 2.20.1