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#include <stdio.h>
#include <stdint.h>
#include "driver/i2c.h"

#define I2C_MASTER_SCL_IO    27   /*!< gpio number for I2C master clock */
#define I2C_MASTER_SDA_IO    14
    /*!< gpio number for I2C master data  */
#define I2C_MASTER_NUM I2C_NUM_0   /*!< I2C port number for master dev */
#define I2C_MASTER_TX_BUF_DISABLE   0   /*!< I2C master do not need buffer */
#define I2C_MASTER_RX_BUF_DISABLE   0   /*!< I2C master do not need buffer */
#define I2C_MASTER_FREQ_HZ    100000     /*!< I2C master clock frequency */

#define MA12040_ADDR  0x20   /*!< slave address for MA12040 amplifier */

#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()
{   int i2c_master_port = I2C_MASTER_NUM;
    i2c_config_t conf;
    conf.mode = I2C_MODE_MASTER;
    conf.sda_io_num = I2C_MASTER_SDA_IO;
    conf.sda_pullup_en = GPIO_PULLUP_ENABLE;
    conf.scl_io_num = I2C_MASTER_SCL_IO;
    conf.scl_pullup_en = GPIO_PULLUP_ENABLE;
    conf.master.clk_speed = I2C_MASTER_FREQ_HZ;
    esp_err_t res = i2c_param_config(i2c_master_port, &conf);
    printf("Driver param setup : %d\n",res);
	res = i2c_driver_install(i2c_master_port, conf.mode, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0);
    printf("Driver installed   : %d\n",res);
}

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esp_err_t ma_write_byte(uint8_t address, uint8_t value)
{
  i2c_cmd_handle_t cmd = i2c_cmd_link_create();
  i2c_master_start(cmd);
  i2c_master_write_byte(cmd, (MA12040_ADDR<<1) | WRITE_BIT , ACK_CHECK_EN);
  i2c_master_write_byte(cmd, address, ACK_VAL);
  i2c_master_write_byte(cmd, value, ACK_VAL);
  i2c_master_stop(cmd); 
  esp_err_t ret = i2c_master_cmd_begin(I2C_MASTER_NUM, cmd, 20 / portTICK_RATE_MS);
  i2c_cmd_link_delete(cmd);
  if (ret == ESP_FAIL) {
     printf("ESP_I2C_WRITE ERROR : %d\n",ret);
	 return ret;
  }
  return ESP_OK;
}

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esp_err_t i2c_master_read(i2c_cmd_handle_t cmd_handle, uint8_t* data, size_t data_len, int ack)
{
    I2C_CHECK((data != NULL), I2C_ADDR_ERROR_STR, ESP_ERR_INVALID_ARG);
    I2C_CHECK(cmd_handle != NULL, I2C_CMD_LINK_INIT_ERR_STR, ESP_ERR_INVALID_ARG);

    int len_tmp;
    int data_offset = 0;
    esp_err_t ret;
    while (data_len > 0) {
        len_tmp = data_len > 0xff ? 0xff : data_len;
        data_len -= len_tmp;
        i2c_cmd_t cmd;
        cmd.ack_en = 0;
        cmd.ack_exp = 0;
        cmd.ack_val = ack & 0x1;
        cmd.byte_num = len_tmp;
        cmd.op_code = I2C_CMD_READ;
        cmd.data = data + data_offset;
        ret = i2c_cmd_link_append(cmd_handle, &cmd);
        data_offset += len_tmp;
        if (ret != ESP_OK) {
            return ret;
        }
    }
    return ESP_OK;
}

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esp_err_t ma_read(uint8_t address, uint8_t *rbuf, uint8_t n)
{ esp_err_t ret;
  i2c_cmd_handle_t cmd = i2c_cmd_link_create();
  
  i2c_master_start(cmd);
  i2c_master_write_byte(cmd, (MA12040_ADDR<<1) | WRITE_BIT, ACK_CHECK_EN);
  i2c_master_write_byte(cmd, address, ACK_VAL);
  i2c_master_start(cmd);
  i2c_master_write_byte(cmd, (MA12040_ADDR<<1) | READ_BIT, ACK_CHECK_EN);
  for (uint8_t i = 0;i<n;i++) 
  { i2c_master_read_byte(cmd, rbuf++, ACK_VAL);
  }
  i2c_master_read_byte(cmd, rbuf++, NACK_VAL);
  i2c_master_stop(cmd);
  ret = i2c_master_cmd_begin(I2C_MASTER_NUM, cmd, 20 / portTICK_RATE_MS);
  i2c_cmd_link_delete(cmd);
  if (ret == ESP_FAIL) {
      printf("i2c Error read - readback\n");
	  return ESP_FAIL;
  }
  return ret; 
}