I2C CODE¶
Component Architecture¶
driver/spi/CMakeLists.txt¶
set(src_dirs
.
)
set(include_dirs
include
)
set(requires
driver
unity
log
)
idf_component_register(SRC_DIRS ${src_dirs} INCLUDE_DIRS ${include_dirs} REQUIRES ${requires})
Note
Note that in the drivers, we used i2c and gpio related functions from the builtin driver library, therefore, we need to indicate these dependencies in the CMakeLists.txt file by adding driver to the REQUIRES field.
i2c.h¶
/**
* @file i2c.c
* @author SHUAIWEN CUI (SHUAIWEN001@e.ntu.edu.sg)
* @brief This file contains the function prototypes for i2c master initialization. This is to serve the peripherals that require I2C communication.
* @version 1.0
* @date 2025-03-17
*
* @copyright Copyright (c) 2025
*
*/
#ifndef __I2C_H__
#define __I2C_H__
#ifdef __cplusplus
extern "C"
{
#endif
#include <stdio.h>
#include "esp_log.h"
#include "unity.h" // This is for unity testing
#include "driver/i2c.h"
#include "esp_system.h"
#define I2C_MASTER_SCL_IO 4 /*!< gpio number for I2C master clock */
#define I2C_MASTER_SDA_IO 5 /*!< gpio number for I2C master data */
#define I2C_MASTER_NUM I2C_NUM_0 /*!< I2C port number for master dev */
#define I2C_MASTER_FREQ_HZ 100000 /*!< I2C master clock frequency */
/**
* @brief i2c master initialization
*/
void i2c_bus_init(void);
#ifdef __cplusplus
}
#endif
#endif /* __I2C_H__ */
i2c.h¶
/**
* @file i2c.c
* @author SHUAIWEN CUI (SHUAIWEN001@e.ntu.edu.sg)
* @brief This file contains the function prototypes for i2c master initialization. This is to serve the peripherals that require I2C communication.
* @version 1.0
* @date 2025-03-17
*
* @copyright Copyright (c) 2025
*
*/
#ifndef __I2C_H__
#define __I2C_H__
#include <stdio.h>
#include "esp_log.h"
#include "unity.h" // This is for unity testing
#include "driver/i2c.h"
#include "esp_system.h"
#define I2C_MASTER_SCL_IO 4 /*!< gpio number for I2C master clock */
#define I2C_MASTER_SDA_IO 5 /*!< gpio number for I2C master data */
#define I2C_MASTER_NUM I2C_NUM_0 /*!< I2C port number for master dev */
#define I2C_MASTER_FREQ_HZ 100000 /*!< I2C master clock frequency */
/**
* @brief i2c master initialization
*/
void i2c_bus_init(void);
#endif /* __I2C_H__ */
i2c.c¶
/**
* @file i2c.c
* @author SHUAIWEN CUI (SHUAIWEN001@e.ntu.edu.sg)
* @brief This file contains the function prototypes for i2c master initialization. This is to serve the peripherals that require I2C communication.
* @version 1.0
* @date 2025-03-17
*
* @copyright Copyright (c) 2025
*
*/
#include "i2c.h"
/**
* @brief i2c master initialization
*/
void i2c_bus_init(void)
{
i2c_config_t conf;
conf.mode = I2C_MODE_MASTER;
conf.sda_io_num = (gpio_num_t)I2C_MASTER_SDA_IO;
conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
conf.scl_io_num = (gpio_num_t)I2C_MASTER_SCL_IO;
conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
conf.master.clk_speed = I2C_MASTER_FREQ_HZ;
conf.clk_flags = I2C_SCLK_SRC_FLAG_FOR_NOMAL;
esp_err_t ret = i2c_param_config(I2C_MASTER_NUM, &conf);
TEST_ASSERT_EQUAL_MESSAGE(ESP_OK, ret, "I2C config returned error");
ret = i2c_driver_install(I2C_MASTER_NUM, conf.mode, 0, 0, 0);
TEST_ASSERT_EQUAL_MESSAGE(ESP_OK, ret, "I2C install returned error");
}
main.c¶
Note
Please note that, the code in this chapter should be used in conjunction with other components that use the i2c to see the effect. Before you use the components based on i2c communication, you need to initialize the i2c bus by calling the i2c_bus_init() function in the main.c file.