/** * Copyright (c) 2020 Raspberry Pi (Trading) Ltd. * * SPDX-License-Identifier: BSD-3-Clause */ #include <stdio.h> #include <string.h> #include "pico/stdlib.h" #include "pico/binary_info.h" #include "hardware/i2c.h" /* Example code to talk to a MPU6050 MEMS accelerometer and gyroscope This is taking to simple approach of simply reading registers. It's perfectly possible to link up an interrupt line and set things up to read from the inbuilt FIFO to make it more useful. NOTE: Ensure the device is capable of being driven at 3.3v NOT 5v. The Pico GPIO (and therefore I2C) cannot be used at 5v. You will need to use a level shifter on the I2C lines if you want to run the board at 5v. Connections on Raspberry Pi Pico board, other boards may vary. GPIO PICO_DEFAULT_I2C_SDA_PIN (On Pico this is GP4 (pin 6)) -> SDA on MPU6050 board GPIO PICO_DEFAULT_I2C_SCL_PIN (On Pico this is GP5 (pin 7)) -> SCL on MPU6050 board 3.3v (pin 36) -> VCC on MPU6050 board GND (pin 38) -> GND on MPU6050 board */ // By default these devices are on bus address 0x68 static int addr = 0x68; #ifdef i2c_default static void mpu6050_reset() { // Two byte reset. First byte register, second byte data // There are a load more options to set up the device in different ways that could be added here uint8_t buf[] = {0x6B, 0x80}; i2c_write_blocking(i2c_default, addr, buf, 2, false); sleep_ms(100); // Allow device to reset and stabilize // Clear sleep mode (0x6B register, 0x00 value) buf[1] = 0x00; // Clear sleep mode by writing 0x00 to the 0x6B register i2c_write_blocking(i2c_default, addr, buf, 2, false); sleep_ms(10); // Allow stabilization after waking up } static void mpu6050_read_raw(int16_t accel[3], int16_t gyro[3], int16_t *temp) { // For this particular device, we send the device the register we want to read // first, then subsequently read from the device. The register is auto incrementing // so we don't need to keep sending the register we want, just the first. uint8_t buffer[6]; // Start reading acceleration registers from register 0x3B for 6 bytes uint8_t val = 0x3B; i2c_write_blocking(i2c_default, addr, &val, 1, true); // true to keep master control of bus i2c_read_blocking(i2c_default, addr, buffer, 6, false); for (int i = 0; i < 3; i++) { accel[i] = (buffer[i * 2] << 8 | buffer[(i * 2) + 1]); } // Now gyro data from reg 0x43 for 6 bytes // The register is auto incrementing on each read val = 0x43; i2c_write_blocking(i2c_default, addr, &val, 1, true); i2c_read_blocking(i2c_default, addr, buffer, 6, false); // False - finished with bus for (int i = 0; i < 3; i++) { gyro[i] = (buffer[i * 2] << 8 | buffer[(i * 2) + 1]);; } // Now temperature from reg 0x41 for 2 bytes // The register is auto incrementing on each read val = 0x41; i2c_write_blocking(i2c_default, addr, &val, 1, true); i2c_read_blocking(i2c_default, addr, buffer, 2, false); // False - finished with bus *temp = buffer[0] << 8 | buffer[1]; } #endif int main() { stdio_init_all(); #if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN) #warning i2c/mpu6050_i2c example requires a board with I2C pins puts("Default I2C pins were not defined"); return 0; #else printf("Hello, MPU6050! Reading raw data from registers...\n"); // This example will use I2C0 on the default SDA and SCL pins (4, 5 on a Pico) i2c_init(i2c_default, 400 * 1000); 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); // Make the I2C pins available to picotool bi_decl(bi_2pins_with_func(PICO_DEFAULT_I2C_SDA_PIN, PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C)); mpu6050_reset(); int16_t acceleration[3], gyro[3], temp; while (1) { mpu6050_read_raw(acceleration, gyro, &temp); // These are the raw numbers from the chip, so will need tweaking to be really useful. // See the datasheet for more information printf("Acc. X = %d, Y = %d, Z = %d\n", acceleration[0], acceleration[1], acceleration[2]); printf("Gyro. X = %d, Y = %d, Z = %d\n", gyro[0], gyro[1], gyro[2]); // Temperature is simple so use the datasheet calculation to get deg C. // Note this is chip temperature. printf("Temp. = %f\n", (temp / 340.0) + 36.53); sleep_ms(100); } #endif }

This firmware image was imported from the pico-examples repository. 


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