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Merge pull request #160 from sheinz/feature/bmp280

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BMP280 pressure sensor driver and example.
This commit is contained in:
Angus Gratton 2016-07-19 08:22:14 +10:00 committed by GitHub
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examples/bmp280/Makefile Normal file
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PROGRAM=BMP280_example
EXTRA_COMPONENTS = extras/i2c extras/bmp280
include ../../common.mk

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examples/bmp280/bmp280_example.c Normal file
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#include <stdio.h>
#include "espressif/esp_common.h"
#include "esp/uart.h"
#include "FreeRTOS.h"
#include "task.h"
#include "bmp280/bmp280.h"
// In forced mode user initiate measurement each time.
// In normal mode measurement is done continuously with specified standby time.
// #define MODE_FORCED
const uint8_t scl_pin = 5;
const uint8_t sda_pin = 4;
#ifdef MODE_FORCED
static void bmp280_task_forced(void *pvParameters)
{
bmp280_params_t params;
float pressure, temperature;
bmp280_init_default_params(&params);
params.mode = BMP280_MODE_FORCED;
while (1) {
while (!bmp280_init(&params, scl_pin, sda_pin)) {
printf("BMP280 initialization failed\n");
vTaskDelay(1000 / portTICK_RATE_MS);
}
while(1) {
vTaskDelay(1000 / portTICK_RATE_MS);
if (!bmp280_force_measurement()) {
printf("Failed initiating measurement\n");
break;
}
while (bmp280_is_measuring()) {}; // wait for measurement to complete
if (!bmp280_read(&temperature, &pressure)) {
printf("Temperature/pressure reading failed\n");
break;
}
printf("Pressure: %.2f Pa, Temperature: %.2f C\n", pressure, temperature);
}
}
}
#else
static void bmp280_task_normal(void *pvParameters)
{
bmp280_params_t params;
float pressure, temperature;
bmp280_init_default_params(&params);
while (1) {
while (!bmp280_init(&params, scl_pin, sda_pin)) {
printf("BMP280 initialization failed\n");
vTaskDelay(1000 / portTICK_RATE_MS);
}
while(1) {
vTaskDelay(1000 / portTICK_RATE_MS);
if (!bmp280_read(&temperature, &pressure)) {
printf("Temperature/pressure reading failed\n");
break;
}
printf("Pressure: %.2f Pa, Temperature: %.2f C\n", pressure, temperature);
}
}
}
#endif
void user_init(void)
{
uart_set_baud(0, 115200);
// Just some information
printf("\n");
printf("SDK version : %s\n", sdk_system_get_sdk_version());
printf("GIT version : %s\n", GITSHORTREV);
#ifdef MODE_FORCED
xTaskCreate(bmp280_task_forced, (signed char *)"bmp280_task", 256, NULL, 2, NULL);
#else
xTaskCreate(bmp280_task_normal, (signed char *)"bmp280_task", 256, NULL, 2, NULL);
#endif
}

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extras/bmp280/README.md Normal file
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# Driver for BMP280 absolute barometric pressure sensor
The driver works only with BMP280 sensor. For BMP080/BMP180 there's a separate
driver. Even though BMP280 is a successor of BMP180 they are not compatible.
They have different registers and different operation modes.
BMP280 supports two ways of communication: spi and i2c.
This driver provides only i2c communication.
The driver is written for [esp-open-rtos](https://github.com/SuperHouse/esp-open-rtos)
framework and requires [i2c driver](https://github.com/SuperHouse/esp-open-rtos/tree/master/extras/i2c)
from it.
## Features
* I2C communication.
* Forced mode (Similar to BMP180 operation).
* Normal mode. Continuous measurement.
* Soft reset.
## Usage
Connect BMP280 module to you ESP8266 module and specify SCL and SDA pins:
```
const uint8_t scl_pin = 5;
const uint8_t sda_pin = 4;
```
Pull up SDO pin of BMP280 in order to have address 0x77.
Or pull down SDO pin and change `#define BMP280_ADDRESS 0x77` to
`#define BMP280_ADDRESS 0x76`. Otherwise your sensor will not work.
By default address 0x77 is used, so SDO pin should be high.
BMP280 supports two operation modes.
### Forced mode
In forced mode, a single measurement is performed according to selected
configuration. When the measurement is finished, the sensor returns to
sleep mode and the measurement results can be read.
### Normal mode
Normal mode continuously cycles between measurement period and standby period,
whose time is defined by standby_time.
## Example
### Forced mode
```
const uint8_t scl_pin = 5;
const uint8_t sda_pin = 4;
bmp280_params_t params;
float pressure, temperature;
bmp280_init_default_params(&params);
params.mode = BMP280_MODE_FORCED;
bmp280_init(&params, scl_pin, sda_pin);
while (1) {
bmp280_force_measurement();
while (bmp280_is_measuring()) {}; // wait for measurement to complete
bmp280_read(&temperature, &pressure);
printf("Pressure: %.2f Pa, Temperature: %.2f C\n", pressure, temperature);
vTaskDelay(1000 / portTICK_RATE_MS);
}
```
### Normal mode
```
bmp280_params_t params;
float pressure, temperature;
bmp280_init_default_params(&params);
bmp280_init(&params, scl_pin, sda_pin);
while (1) {
bmp280_read(&temperature, &pressure);
printf("Pressure: %.2f Pa, Temperature: %.2f C\n", pressure, temperature);
vTaskDelay(1000 / portTICK_RATE_MS);
}
```
## License
The driver is released under MIT license.
Copyright (c) 2016 sheinz (https://github.com/sheinz)

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extras/bmp280/bmp280.c Normal file
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/**
* The MIT License (MIT)
*
* Copyright (c) 2016 sheinz (https://github.com/sheinz)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "bmp280.h"
#include "i2c/i2c.h"
#ifdef BMP280_DEBUG
#include <stdio.h>
#define debug(fmt, ...) printf("%s" fmt "\n", "bmp280: ", ## __VA_ARGS__);
#else
#define debug(fmt, ...)
#endif
/**
* BMP280 registers
*/
#define BMP280_REG_TEMP_XLSB 0xFC /* bits: 7-4 */
#define BMP280_REG_TEMP_LSB 0xFB
#define BMP280_REG_TEMP_MSB 0xFA
#define BMP280_REG_TEMP (BMP280_REG_TEMP_MSB)
#define BMP280_REG_PRESS_XLSB 0xF9 /* bits: 7-4 */
#define BMP280_REG_PRESS_LSB 0xF8
#define BMP280_REG_PRESS_MSB 0xF7
#define BMP280_REG_PRESSURE (BMP280_REG_PRESS_MSB)
#define BMP280_REG_CONFIG 0xF5 /* bits: 7-5 t_sb; 4-2 filter; 0 spi3w_en */
#define BMP280_REG_CTRL 0xF4 /* bits: 7-5 osrs_t; 4-2 osrs_p; 1-0 mode */
#define BMP280_REG_STATUS 0xF3 /* bits: 3 measuring; 0 im_update */
#define BMP280_REG_RESET 0xE0
#define BMP280_REG_ID 0xD0
#define BMP280_REG_CALIB 0x88
#define BMP280_CHIP_ID 0x58 /* BMP280 has chip-id 0x58 */
#define BMP280_RESET_VALUE 0xB6
typedef struct __attribute__((packed)) {
uint16_t dig_T1;
int16_t dig_T2;
int16_t dig_T3;
uint16_t dig_P1;
int16_t dig_P2;
int16_t dig_P3;
int16_t dig_P4;
int16_t dig_P5;
int16_t dig_P6;
int16_t dig_P7;
int16_t dig_P8;
int16_t dig_P9;
} BMP280_Calib;
static BMP280_Calib calib_data;
void bmp280_init_default_params(bmp280_params_t *params)
{
params->mode = BMP280_MODE_NORMAL;
params->filter = BMP280_FILTER_OFF;
params->oversampling = BMP280_STANDARD;
params->standby = BMP280_STANDBY_250;
}
static uint8_t read_register8(uint8_t addr)
{
uint8_t r = 0;
if (!i2c_slave_read(BMP280_ADDRESS, addr, &r, 1)) {
r = 0;
}
return r;
}
/**
* Even though value is signed the actual value is always positive.
* So, no need to take care of sign bit.
*/
static bool read_register24(uint8_t addr, int32_t *value)
{
uint8_t d[] = {0, 0, 0};
if (i2c_slave_read(BMP280_ADDRESS, addr, d, sizeof(d))) {
*value = d[0];
*value <<= 8;
*value |= d[1];
*value <<= 4;
*value |= d[2]>>4;
return true;
}
return false;
}
static bool check_chip_id()
{
return (read_register8(BMP280_REG_ID)==BMP280_CHIP_ID);
}
static bool read_calibration_data()
{
if (!i2c_slave_read(BMP280_ADDRESS, BMP280_REG_CALIB,
(uint8_t*)&calib_data, sizeof(calib_data))) {
return false;
}
debug("Calibration data received:");
debug("dig_T1=%d", calib_data.dig_T1);
debug("dig_T2=%d", calib_data.dig_T2);
debug("dig_T3=%d", calib_data.dig_T3);
debug("dig_P1=%d", calib_data.dig_P1);
debug("dig_P2=%d", calib_data.dig_P2);
debug("dig_P3=%d", calib_data.dig_P3);
debug("dig_P4=%d", calib_data.dig_P4);
debug("dig_P5=%d", calib_data.dig_P5);
debug("dig_P6=%d", calib_data.dig_P6);
debug("dig_P7=%d", calib_data.dig_P7);
debug("dig_P8=%d", calib_data.dig_P8);
debug("dig_P9=%d", calib_data.dig_P9);
return true;
}
static bool write_register8(uint8_t addr, uint8_t value)
{
uint8_t d[] = {addr, value};
return i2c_slave_write(BMP280_ADDRESS, d, 2);
}
bool bmp280_init(bmp280_params_t *params, uint8_t scl_pin, uint8_t sda_pin)
{
i2c_init(scl_pin, sda_pin);
if (!check_chip_id()) {
debug("Sensor not found or wrong sensor version");
return false;
}
if (!read_calibration_data()) {
debug("Failed to read calibration data");
return false;
}
uint8_t config = (params->standby << 5) | (params->filter << 2);
debug("Writing config reg=%x", config);
if (!write_register8(BMP280_REG_CONFIG, config)) {
debug("Failed configuring sensor");
return false;
}
uint8_t oversampling_temp =
(params->oversampling == BMP280_ULTRA_HIGH_RES) ? 2 : 1;
if (params->mode == BMP280_MODE_FORCED) {
params->mode = BMP280_MODE_SLEEP; // initial mode for forced is sleep
}
uint8_t ctrl = (oversampling_temp << 5) | (params->oversampling << 2)
| (params->mode);
debug("Writing ctrl reg=%x", ctrl);
if (!write_register8(BMP280_REG_CTRL, ctrl)) {
debug("Failed controlling sensor");
return false;
}
return true;
}
bool bmp280_force_measurement()
{
uint8_t ctrl = read_register8(BMP280_REG_CTRL);
ctrl &= ~0b11; // clear two lower bits
ctrl |= BMP280_MODE_FORCED;
debug("Writing ctrl reg=%x", ctrl);
if (!write_register8(BMP280_REG_CTRL, ctrl)) {
debug("Failed starting forced mode");
return false;
}
return true;
}
bool bmp280_is_measuring()
{
uint8_t status = read_register8(BMP280_REG_STATUS);
if (status & (1<<3)) {
debug("Status: measuring");
return true;
}
debug("Status: idle");
return false;
}
/**
* Compensation algorithm is taken from BMP280 datasheet.
*
* Return value is in degrees Celsius.
*/
static inline float compensate_temperature(int32_t raw_temp, int32_t *fine_temp)
{
int32_t var1, var2, T;
var1 = ((((raw_temp>>3) - ((int32_t)calib_data.dig_T1<<1)))
* ((int32_t)calib_data.dig_T2)) >> 11;
var2 = (((((raw_temp>>4) - ((int32_t)calib_data.dig_T1))
* ((raw_temp>>4) - ((int32_t)calib_data.dig_T1))) >> 12)
* ((int32_t)calib_data.dig_T3)) >> 14;
*fine_temp = var1 + var2;
T = (*fine_temp * 5 + 128) >> 8;
return (float)T/100;
}
/**
* Compensation algorithm is taken from BMP280 datasheet.
*
* Return value is in Pa.
*/
static inline float compensate_pressure(int32_t raw_press, int32_t fine_temp)
{
int64_t var1, var2, p;
var1 = ((int64_t)fine_temp) - 128000;
var2 = var1 * var1 * (int64_t)calib_data.dig_P6;
var2 = var2 + ((var1*(int64_t)calib_data.dig_P5)<<17);
var2 = var2 + (((int64_t)calib_data.dig_P4)<<35);
var1 = ((var1 * var1 * (int64_t)calib_data.dig_P3)>>8) +
((var1 * (int64_t)calib_data.dig_P2)<<12);
var1 = (((((int64_t)1)<<47)+var1))*((int64_t)calib_data.dig_P1)>>33;
if (var1 == 0) {
return 0; // avoid exception caused by division by zero
}
p = 1048576 - raw_press;
p = (((p<<31) - var2)*3125) / var1;
var1 = (((int64_t)calib_data.dig_P9) * (p>>13) * (p>>13)) >> 25;
var2 = (((int64_t)calib_data.dig_P8) * p) >> 19;
p = ((p + var1 + var2) >> 8) + (((int64_t)calib_data.dig_P7)<<4);
return (float)p/256;
}
bool bmp280_read(float *temperature, float *pressure)
{
int32_t raw_pressure;
int32_t raw_temp;
int32_t fine_temp;
if (!read_register24(BMP280_REG_TEMP, &raw_temp)) {
debug("Failed reading temperature");
return false;
}
if (!read_register24(BMP280_REG_PRESSURE, &raw_pressure)) {
debug("Failed reading pressure");
return false;
}
debug("Raw temperature: %d", raw_temp);
debug("Raw pressure: %d", raw_pressure);
*temperature = compensate_temperature(raw_temp, &fine_temp);
*pressure = compensate_pressure(raw_pressure, fine_temp);
return true;
}
bool bmp280_soft_reset()
{
if (!write_register8(BMP280_REG_RESET, BMP280_RESET_VALUE)) {
debug("Failed resetting sensor");
return false;
}
return true;
}

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/**
* The MIT License (MIT)
*
* Copyright (c) 2016 sheinz (https://github.com/sheinz)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef __BMP280_H__
#define __BMP280_H__
#include <stdint.h>
#include <stdbool.h>
/**
* Uncomment to enable debug output.
*/
// #define BMP280_DEBUG
/**
* BMP280 address is 0x77 if SDO pin is high,
* Address is 0x76 if SDO pin is low.
*/
#define BMP280_ADDRESS 0x77
/**
* Mode of BMP280 module operation.
* Forced - Measurement is initiated by user.
* Normal - Continues measurement.
*/
typedef enum {
BMP280_MODE_SLEEP = 0,
BMP280_MODE_FORCED = 1,
BMP280_MODE_NORMAL = 3
} BMP280_Mode;
typedef enum {
BMP280_FILTER_OFF = 0,
BMP280_FILTER_2 = 1,
BMP280_FILTER_4 = 2,
BMP280_FILTER_8 = 3,
BMP280_FILTER_16 = 4
} BMP280_Filter;
/**
* Pressure oversampling settings
*/
typedef enum {
BMP280_ULTRA_LOW_POWER = 1, /* oversampling x1 */
BMP280_LOW_POWER = 2, /* oversampling x2 */
BMP280_STANDARD = 3, /* oversampling x4 */
BMP280_HIGH_RES = 4, /* oversampling x8 */
BMP280_ULTRA_HIGH_RES = 5 /* oversampling x16 */
} BMP280_Oversampling;
/**
* Stand by time between measurements in normal mode
*/
typedef enum {
BMP280_STANDBY_05 = 0, /* stand by time 0.5ms */
BMP280_STANDBY_62 = 1, /* stand by time 62.5ms */
BMP280_STANDBY_125 = 2, /* stand by time 125ms */
BMP280_STANDBY_250 = 3, /* stand by time 250ms */
BMP280_STANDBY_500 = 4, /* stand by time 500ms */
BMP280_STANDBY_1000 = 5, /* stand by time 1s */
BMP280_STANDBY_2000 = 6, /* stand by time 2s */
BMP280_STANDBY_4000 = 7, /* stand by time 4s */
} BMP280_StandbyTime;
/**
* Configuration parameters for BMP280 module.
* Use function bmp280_init_default_params to use default configuration.
*/
typedef struct {
BMP280_Mode mode;
BMP280_Filter filter;
BMP280_Oversampling oversampling; // pressure oversampling
BMP280_StandbyTime standby;
} bmp280_params_t;
/**
* Initialize default parameters.
* Default configuration:
* mode: NORAML
* filter: OFF
* oversampling: x4
* standby time: 250ms
*/
void bmp280_init_default_params(bmp280_params_t *params);
/**
* Initialize BMP280 module.
*/
bool bmp280_init(bmp280_params_t *params, uint8_t scl_pin, uint8_t sda_pin);
/**
* Start measurement in forced mode.
* The module remains in forced mode after this call.
* Do not call this method in normal mode.
*/
bool bmp280_force_measurement();
/**
* Check if BMP280 is busy with measuring temperature/pressure.
* Return true if BMP280 is busy.
*/
bool bmp280_is_measuring();
/**
* Read compensated temperature and pressure data.
* Temperature in degrees Celsius.
* Pressure in Pascals.
*/
bool bmp280_read(float *temperature, float *pressure);
/**
* Restart BMP280 module.
*/
bool bmp280_soft_reset();
#endif // __BMP280_H__

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# Component makefile for extras/bmp280
# expected anyone using bmp driver includes it as 'bmp280/bmp280.h'
INC_DIRS += $(bmp280_ROOT)..
# args for passing into compile rule generation
bmp280_SRC_DIR = $(bmp280_ROOT)
$(eval $(call component_compile_rules,bmp280))