392 lines
10 KiB
C
392 lines
10 KiB
C
/****************************************************************************
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* drivers/sensors/bmp180_base.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/* Character driver for the Freescale BMP1801 Barometer Sensor */
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include "bmp180_base.h"
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#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_BMP180)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Type Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: bmp180_getreg8
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*
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* Description:
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* Read from an 8-bit BMP180 register
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*
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****************************************************************************/
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uint8_t bmp180_getreg8(FAR struct bmp180_dev_s *priv, uint8_t regaddr)
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{
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struct i2c_config_s config;
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uint8_t regval = 0;
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int ret;
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/* Set up the I2C configuration */
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config.frequency = priv->freq;
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config.address = priv->addr;
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config.addrlen = 7;
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/* Write the register address */
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ret = i2c_write(priv->i2c, &config, ®addr, 1);
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if (ret < 0)
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{
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snerr("ERROR: i2c_write failed: %d\n", ret);
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return ret;
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}
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/* Read the register value */
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ret = i2c_read(priv->i2c, &config, ®val, 1);
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if (ret < 0)
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{
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snerr("ERROR: i2c_read failed: %d\n", ret);
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return ret;
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}
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return regval;
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}
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/****************************************************************************
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* Name: bmp180_getreg16
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*
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* Description:
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* Read two 8-bit from a BMP180 register
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*
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****************************************************************************/
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uint16_t bmp180_getreg16(FAR struct bmp180_dev_s *priv, uint8_t regaddr)
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{
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struct i2c_config_s config;
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uint16_t msb;
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uint16_t lsb;
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uint16_t regval = 0;
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int ret;
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/* Set up the I2C configuration */
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config.frequency = priv->freq;
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config.address = priv->addr;
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config.addrlen = 7;
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/* Register to read */
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ret = i2c_write(priv->i2c, &config, ®addr, 1);
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if (ret < 0)
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{
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snerr("ERROR: i2c_write failed: %d\n", ret);
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return ret;
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}
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/* Read register */
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ret = i2c_read(priv->i2c, &config, (FAR uint8_t *)®val, 2);
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if (ret < 0)
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{
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snerr("ERROR: i2c_read failed: %d\n", ret);
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return ret;
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}
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/* MSB and LSB are inverted */
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msb = (regval & 0xff);
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lsb = (regval & 0xff00) >> 8;
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regval = (msb << 8) | lsb;
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return regval;
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}
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/****************************************************************************
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* Name: bmp180_putreg8
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*
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* Description:
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* Write to an 8-bit BMP180 register
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*
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****************************************************************************/
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void bmp180_putreg8(FAR struct bmp180_dev_s *priv, uint8_t regaddr,
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uint8_t regval)
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{
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struct i2c_config_s config;
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uint8_t data[2];
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int ret;
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/* Set up the I2C configuration */
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config.frequency = priv->freq;
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config.address = priv->addr;
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config.addrlen = 7;
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data[0] = regaddr;
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data[1] = regval;
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/* Write the register address and value */
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ret = i2c_write(priv->i2c, &config, (FAR uint8_t *)&data, 2);
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if (ret < 0)
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{
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snerr("ERROR: i2c_write failed: %d\n", ret);
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return;
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}
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}
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/****************************************************************************
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* Name: bmp180_checkid
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*
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* Description:
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* Read and verify the BMP180 chip ID
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*
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****************************************************************************/
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int bmp180_checkid(FAR struct bmp180_dev_s *priv)
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{
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uint8_t devid = 0;
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/* Read device ID */
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devid = bmp180_getreg8(priv, BMP180_DEVID);
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sninfo("devid: 0x%02x\n", devid);
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if (devid != (uint16_t)DEVID)
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{
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/* ID is not Correct */
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snerr("ERROR: Wrong Device ID!\n");
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return -ENODEV;
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}
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return OK;
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}
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/****************************************************************************
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* Name: bmp180_updatecaldata
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*
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* Description:
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* Update Calibration Coefficient Data
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*
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****************************************************************************/
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void bmp180_updatecaldata(FAR struct bmp180_dev_s *priv)
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{
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/* AC1 */
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priv->bmp180_cal_ac1 = (int16_t) bmp180_getreg16(priv, BMP180_AC1_MSB);
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/* AC2 */
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priv->bmp180_cal_ac2 = (int16_t) bmp180_getreg16(priv, BMP180_AC2_MSB);
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/* AC3 */
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priv->bmp180_cal_ac3 = (int16_t) bmp180_getreg16(priv, BMP180_AC3_MSB);
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/* AC4 */
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priv->bmp180_cal_ac4 = bmp180_getreg16(priv, BMP180_AC4_MSB);
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/* AC5 */
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priv->bmp180_cal_ac5 = bmp180_getreg16(priv, BMP180_AC5_MSB);
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/* AC6 */
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priv->bmp180_cal_ac6 = bmp180_getreg16(priv, BMP180_AC6_MSB);
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/* B1 */
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priv->bmp180_cal_b1 = (int16_t) bmp180_getreg16(priv, BMP180_B1_MSB);
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/* B2 */
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priv->bmp180_cal_b2 = (int16_t) bmp180_getreg16(priv, BMP180_B2_MSB);
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/* MB */
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priv->bmp180_cal_mb = (int16_t) bmp180_getreg16(priv, BMP180_MB_MSB);
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/* MC */
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priv->bmp180_cal_mc = (int16_t) bmp180_getreg16(priv, BMP180_MC_MSB);
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/* MD */
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priv->bmp180_cal_md = (int16_t) bmp180_getreg16(priv, BMP180_MD_MSB);
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}
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/****************************************************************************
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* Name: bmp180_read_press_temp
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*
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* Description:
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* Read raw pressure and temperature from BMP180 and store it in the
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* bmp180_dev_s structure.
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*
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****************************************************************************/
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void bmp180_read_press_temp(FAR struct bmp180_dev_s *priv)
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{
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uint8_t oss = CURRENT_OSS;
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/* Issue a read temperature command */
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bmp180_putreg8(priv, BMP180_CTRL_MEAS, BMP180_READ_TEMP);
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/* Wait 5ms */
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nxsig_usleep(5000);
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/* Read temperature */
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priv->bmp180_utemp = bmp180_getreg16(priv, BMP180_ADC_OUT_MSB);
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/* Issue a read pressure command */
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bmp180_putreg8(priv, BMP180_CTRL_MEAS, (BMP180_READ_PRESS | oss));
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/* Delay 25.5ms (to OverSampling 8X) */
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nxsig_usleep(25500);
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/* Read pressure */
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priv->bmp180_upress = bmp180_getreg16(priv, BMP180_ADC_OUT_MSB) << 8;
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priv->bmp180_upress |= bmp180_getreg8(priv, BMP180_ADC_OUT_XLSB);
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priv->bmp180_upress = priv->bmp180_upress >> (8 - (oss >> 6));
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sninfo("Uncompensated temperature = %" PRId32 "\n", priv->bmp180_utemp);
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sninfo("Uncompensated pressure = %" PRId32 "\n", priv->bmp180_upress);
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}
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/****************************************************************************
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* Name: bmp180_getpressure
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*
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* Description:
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* Calculate the Barometric Pressure using the temperature compensated
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* See Freescale AN3785 and BMP1801 data sheet for details
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*
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****************************************************************************/
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int bmp180_getpressure(FAR struct bmp180_dev_s *priv,
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FAR float *temperature)
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{
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int32_t x1;
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int32_t x2;
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int32_t x3;
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int32_t b3;
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int32_t b5;
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int32_t b6;
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int32_t press;
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int32_t temp;
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uint32_t b4;
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uint32_t b7;
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uint8_t oss = (CURRENT_OSS >> 6);
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/* Check if coefficient data were read correctly */
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if ((priv->bmp180_cal_ac1 == 0) || (priv->bmp180_cal_ac2 == 0) ||
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(priv->bmp180_cal_ac3 == 0) || (priv->bmp180_cal_ac4 == 0) ||
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(priv->bmp180_cal_ac5 == 0) || (priv->bmp180_cal_ac6 == 0) ||
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(priv->bmp180_cal_b1 == 0) || (priv->bmp180_cal_b2 == 0) ||
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(priv->bmp180_cal_mb == 0) || (priv->bmp180_cal_mc == 0) ||
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(priv->bmp180_cal_md == 0))
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{
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bmp180_updatecaldata(priv);
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}
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/* Read temperature and pressure */
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bmp180_read_press_temp(priv);
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/* Feed raw sensor data to entropy pool */
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add_sensor_randomness((priv->bmp180_utemp << 16) ^ priv->bmp180_upress);
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/* Calculate true temperature */
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x1 = ((priv->bmp180_utemp - priv->bmp180_cal_ac6) *
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priv->bmp180_cal_ac5) >> 15;
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x2 = (priv->bmp180_cal_mc << 11) / (x1 + priv->bmp180_cal_md);
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b5 = x1 + x2;
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temp = (b5 + 8) >> 4;
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sninfo("Compensated temperature = %" PRId32 "\n", temp);
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if (temperature != NULL)
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*temperature = temp;
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/* Calculate true pressure */
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b6 = b5 - 4000;
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x1 = (priv->bmp180_cal_b2 * ((b6 * b6) >> 12)) >> 11;
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x2 = (priv->bmp180_cal_ac2 * b6) >> 11;
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x3 = x1 + x2;
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b3 = (((((int32_t) priv->bmp180_cal_ac1) * 4 + x3) << oss) + 2) >> 2;
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x1 = (priv->bmp180_cal_ac3 * b6) >> 13;
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x2 = (priv->bmp180_cal_b1 * ((b6 * b6) >> 12)) >> 16;
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x3 = ((x1 + x2) + 2) >> 2;
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b4 = (priv->bmp180_cal_ac4 * (uint32_t) (x3 + 32768)) >> 15;
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b7 = ((uint32_t) (priv->bmp180_upress - b3) * (50000 >> oss));
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if (b7 < 0x80000000)
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{
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press = (b7 << 1) / b4;
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}
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else
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{
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press = (b7 / b4) << 1;
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}
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x1 = (press >> 8) * (press >> 8);
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x1 = (x1 * 3038) >> 16;
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x2 = (-7357 * press) >> 16;
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press = press + ((x1 + x2 + 3791) >> 4);
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sninfo("Compressed pressure = %" PRId32 "\n", press);
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return press;
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}
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#endif /* CONFIG_I2C && CONFIG_SENSORS_BMP180 */
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