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#include <driver/i2c.h>
#include <esp_log.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <stdio.h>
#include "driver/gpio.h"
#include "sdkconfig.h"

#define WRITE_BIT                     I2C_MASTER_WRITE    	/*!< I2C master write */
#define READ_BIT                       I2C_MASTER_READ     	/*!< I2C master read */
#define ACK_CHECK_EN            0x1                 			/*!< I2C master will check ack from slave*/
#define ACK_CHECK_DIS           0x0                			/*!< I2C master will not check ack from slave */
#define ACK_VAL                        0x0                 			/*!< I2C ack value */
#define NACK_VAL                      0x1                 			/*!< I2C nack value */

void i2c_master_init(){
    i2c_config_t conf;

    conf.mode = I2C_MODE_MASTER;
    conf.sda_io_num = 22;
    conf.scl_io_num = 21;
    conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
    conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
    conf.master.clk_speed = 100000;
    
    i2c_param_config(I2C_NUM_0, &conf);
    i2c_driver_install(I2C_NUM_0, I2C_MODE_MASTER, 0, 0, 0);
}

static esp_err_t i2c_master_device_read(i2c_port_t i2c_num, uint8_t* data_h, uint8_t* data_l){
    int ret;
    i2c_cmd_handle_t cmd = i2c_cmd_link_create();

    i2c_master_start(cmd);
    i2c_master_write_byte(cmd, 0x23 << 1 | WRITE_BIT, ACK_CHECK_EN);
    i2c_master_write_byte(cmd, 0xFF, ACK_CHECK_EN);
    i2c_master_read_byte(cmd, data_h, ACK_VAL);
    i2c_master_read_byte(cmd, data_l, NACK_VAL);
    i2c_master_stop(cmd);

    ret = i2c_master_cmd_begin(I2C_NUM_0, cmd, 1000 / portTICK_RATE_MS);
    i2c_cmd_link_delete(cmd);
    return ret;
}

void task_i2c(void *ignore) {

    esp_err_t ret;
    uint8_t device_l = 0xFF;
    uint8_t device_h = 0xFF;

    while(1){
        ret = i2c_master_device_read(I2C_NUM_0, &device_h, &device_l);
        if(ret == ESP_ERR_TIMEOUT){
            printf("I2C Timeout\n");
        } else if(ret != ESP_OK){
            printf("I2C Error\n");
        } else {
            printf("I2C Device ID\n");
            printf("Device Low: %02x\n", device_l);
            printf("Device High: %02x\n", device_h);
        }
        vTaskDelay(1000 / portTICK_RATE_MS);
    }
    vTaskDelete(NULL);
}    

void app_main(){
    i2c_master_init();
    xTaskCreate(task_i2c, "i2c__task_0", 1024 * 2, (void* ) 0, 10, NULL);
}