init bme_280 lib

bme280.c

@@ -0,0 +1,145 @@
+#include "bme280.h"
+#include "hardware/i2c.h"
+#include "pico/binary_info.h"
+#include "pico/stdlib.h"
+#include <stdint.h>
+#include <stdio.h>
+/*
+    Lib for Bosh BME280 Env Sensor. To be used in weather station context.
+    Sources:
+        - pico example for bmp280 a simpler sensor then bme280 that does not
+        include humidity
+   https://github.com/raspberrypi/pico-examples/blob/master/i2c/bmp280_i2c/bmp280_i2c.c
+        - bme280 datasheet
+   https://cdn.shopify.com/s/files/1/0174/1800/files/bst-bme280-ds002.pdf?v=1662743150
+        - bmp280 datasheet
+   https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bmp280-ds001.pdf
+        - pimoroni eshop
+   https://shop.pimoroni.com/products/bme280-breakout?variant=29420960677971
+        - pimoroni pico sdk
+   https://github.com/boschsensortec/BME280_SensorAPI/tree/c47f06eb44fc96970f0abfcc941ec16425b2a9e6
+*/
+
+// Define the custom pins for I2C
+#define I2C_SDA_PIN 14 // Replace with your custom SDA pin
+#define I2C_SCL_PIN 15 // Replace with your custom SCL pin
+
+// Define the I2C instance to use (i2c0 or i2c1)
+#define I2C_PORT i2c1
+
+// device has default bus address of 0x76
+#define ADDR _u(0x76)
+
+// hardware registers
+#define REG_CONFIG _u(0xF5)
+#define REG_CTRL_MEAS _u(0xF4)
+// #define REG_RESET _u(0xE0)
+
+// #define REG_TEMP_XLSB _u(0xFC)
+// #define REG_TEMP_LSB _u(0xFB)
+// #define REG_TEMP_MSB _u(0xFA)
+
+// #define REG_PRESSURE_XLSB _u(0xF9)
+// #define REG_PRESSURE_LSB _u(0xF8)
+// #define REG_PRESSURE_MSB _u(0xF7)
+
+// calibration registers
+#define REG_DIG_T1_LSB _u(0x88)
+// #define REG_DIG_T1_MSB _u(0x89)
+// #define REG_DIG_T2_LSB _u(0x8A)
+// #define REG_DIG_T2_MSB _u(0x8B)
+// #define REG_DIG_T3_LSB _u(0x8C)
+// #define REG_DIG_T3_MSB _u(0x8D)
+// #define REG_DIG_P1_LSB _u(0x8E)
+// #define REG_DIG_P1_MSB _u(0x8F)
+// #define REG_DIG_P2_LSB _u(0x90)
+// #define REG_DIG_P2_MSB _u(0x91)
+// #define REG_DIG_P3_LSB _u(0x92)
+// #define REG_DIG_P3_MSB _u(0x93)
+// #define REG_DIG_P4_LSB _u(0x94)
+// #define REG_DIG_P4_MSB _u(0x95)
+// #define REG_DIG_P5_LSB _u(0x96)
+// #define REG_DIG_P5_MSB _u(0x97)
+// #define REG_DIG_P6_LSB _u(0x98)
+// #define REG_DIG_P6_MSB _u(0x99)
+// #define REG_DIG_P7_LSB _u(0x9A)
+// #define REG_DIG_P7_MSB _u(0x9B)
+// #define REG_DIG_P8_LSB _u(0x9C)
+// #define REG_DIG_P8_MSB _u(0x9D)
+// #define REG_DIG_P9_LSB _u(0x9E)
+// #define REG_DIG_P9_MSB _u(0x9F)
+
+// number of calibration registers to be read
+// 17 * 2  = 34
+#define NUM_COMPENSATION_PARAMS 34
+
+static void bmp280_get_compensation_params(i2c_inst_t *i2c, bme280_compensation_params *params) {
+  // raw temp and pressure values need to be calibrated according to
+  // parameters generated during the manufacturing of the sensor
+  // there are 3 temperature params, and 9 pressure params, each with a LSB
+  // and MSB register, so we read from 24 registers
+
+  uint8_t buf[NUM_COMPENSATION_PARAMS] = {0};
+  uint8_t reg = REG_DIG_T1_LSB;
+  i2c_write_blocking(i2c, ADDR, &reg, 1,
+                     true); // true to keep master control of bus
+  // read in one go as register addresses auto-increment
+  i2c_read_blocking(i2c, ADDR, buf, NUM_COMPENSATION_PARAMS,
+                    false); // false, we're done reading
+
+  // store these in a struct for later use
+  params->dig_t1 = (uint16_t)(buf[1] << 8) | buf[0];
+  params->dig_t2 = (int16_t)(buf[3] << 8) | buf[2];
+  params->dig_t3 = (int16_t)(buf[5] << 8) | buf[4];
+
+  params->dig_p1 = (uint16_t)(buf[7] << 8) | buf[6];
+  params->dig_p2 = (int16_t)(buf[9] << 8) | buf[8];
+  params->dig_p3 = (int16_t)(buf[11] << 8) | buf[10];
+  params->dig_p4 = (int16_t)(buf[13] << 8) | buf[12];
+  params->dig_p5 = (int16_t)(buf[15] << 8) | buf[14];
+  params->dig_p6 = (int16_t)(buf[17] << 8) | buf[16];
+  params->dig_p7 = (int16_t)(buf[19] << 8) | buf[18];
+  params->dig_p8 = (int16_t)(buf[21] << 8) | buf[20];
+  params->dig_p9 = (int16_t)(buf[23] << 8) | buf[22];
+
+  params->dig_h1 = (int16_t)(buf[25] << 8) | buf[24];
+  params->dig_h2 = (int16_t)(buf[27] << 8) | buf[26];
+  params->dig_h3 = (int16_t)(buf[29] << 8) | buf[28];
+  params->dig_h4 = (int16_t)(buf[31] << 8) | buf[30];
+  params->dig_h5 = (int16_t)(buf[33] << 8) | buf[32];
+}
+
+void bme280_init(bme280_config *config, i2c_inst_t *i2c, uint8_t sda_pin,
+                 uint8_t scl_pin) {
+  i2c_init(i2c, 100 * 1000);
+  gpio_set_function(sda_pin, GPIO_FUNC_I2C);
+  gpio_set_function(scl_pin, GPIO_FUNC_I2C);
+  gpio_pull_up(sda_pin);
+  gpio_pull_up(scl_pin);
+  // use the "handheld device dynamic" optimal setting (see datasheet)
+  // bi_decl(bi_2pins_with_func(sda_pin, scl_pin, GPIO_FUNC_I2C));
+  // bi_decl(bi_program_description("BMP280 I2C LIB"));
+
+  uint8_t buf[2];
+
+  // 500ms sampling time, x16 filter
+  const uint8_t reg_config_val = ((0x04 << 5) | (0x05 << 2)) & 0xFC;
+
+  // send register number followed by its corresponding value
+  buf[0] = REG_CONFIG;
+  buf[1] = reg_config_val;
+  i2c_write_blocking(i2c, ADDR, buf, 2, false);
+
+  // osrs_t x1, osrs_p x4, normal mode operation
+  const uint8_t reg_ctrl_meas_val = (0x01 << 5) | (0x03 << 2) | (0x03);
+  buf[0] = REG_CTRL_MEAS;
+  buf[1] = reg_ctrl_meas_val;
+  i2c_write_blocking(i2c, ADDR, buf, 2, false);
+
+  bme280_compensation_params params;
+  bmp280_get_compensation_params(i2c, &params);
+
+  config->params = params;
+  config->i2c = i2c;
+  return;
+}