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#include <stdio.h>
#include "hardware/gpio.h"
#include "boards/pico_w.h"
#include "hardware/i2c.h"
#include "pico/stdio.h"
#include "pico/time.h"
#define ALT_ADDR 0x60
#define MAX_SCL 400000
#define DATA_RATE_HZ 15
float altitude = 0.0f;
float get_altitude();
int main() {
stdio_init_all();
i2c_init(i2c_default, MAX_SCL);
gpio_set_function(PICO_DEFAULT_I2C_SDA_PIN, GPIO_FUNC_I2C);
gpio_set_function(PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C);
gpio_pull_up(PICO_DEFAULT_I2C_SDA_PIN);
gpio_pull_up(PICO_DEFAULT_I2C_SCL_PIN);
uint8_t config[2] = {0};
// Select control register(0x26)
// Active mode, OSR = 16, altimeter mode(0xB8)
config[0] = 0x26;
config[1] = 0xB9;
i2c_write_blocking(i2c_default, ALT_ADDR, config, 2, true);
sleep_ms(1500);
while (1) {
sleep_ms(1000);
altitude = get_altitude();
printf("Altitude: %4.2f\n", altitude);
}
}
float get_altitude() {
uint8_t reg = 0x01;
uint8_t data[5];
i2c_write_blocking(i2c_default, ALT_ADDR, ®, 1, true);
i2c_read_blocking(i2c_default, ALT_ADDR, data, 5, false);
// Exactly how MPL3115A2 datasheet says to retrieve altitude
float altitude = (float) ((int16_t) ((data[0] << 8) | data[1])) + (float) (data[2] >> 4) * 0.0625;
return altitude;
}
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