text: /*
   * Copyright (c) 2015, Freescale Semiconductor, Inc.
   * Copyright 2016-2017 NXP
   * All rights reserved.
   *
   * SPDX-License-Identifier: BSD-3-Clause
   */
  
  /*  Standard C Included Files */
  #include <string.h>
  /*  SDK Included Files */
  #include "pin_mux.h"
  #include "clock_config.h"
  #include "board.h"
  #include "fsl_debug_console.h"
  #include "fsl_i2c.h"
  
  /*******************************************************************************
   * Definitions
   ******************************************************************************/
  /* I2C source clock */
  #define I2C_MASTER_CLK_SRC          I2C0_CLK_SRC
  #define I2C_MASTER_CLK_FREQ         CLOCK_GetFreq(I2C0_CLK_SRC)
  #define EXAMPLE_I2C_MASTER_BASEADDR I2C0
  
  #define I2C_MASTER_SLAVE_ADDR_7BIT 0x7EU
  #define I2C_BAUDRATE               100000U
  #define I2C_DATA_LENGTH            33U
  
  /*******************************************************************************
   * Prototypes
   ******************************************************************************/
  
  /*******************************************************************************
   * Variables
   ******************************************************************************/
  
  uint8_t g_master_txBuff[I2C_DATA_LENGTH];
  uint8_t g_master_rxBuff[I2C_DATA_LENGTH];
  i2c_master_handle_t g_m_handle;
  volatile bool g_MasterCompletionFlag = false;
  
  /*******************************************************************************
   * Code
   ******************************************************************************/
  
  static void i2c_master_callback(I2C_Type *base, i2c_master_handle_t *handle, status_t status, void *userData)
  {
      /* Signal transfer success when received success status. */
      if (status == kStatus_Success)
      {
          g_MasterCompletionFlag = true;
      }
  }
  
  /*!
   * @brief Main function
   */
  int main(void)
  {
      i2c_master_config_t masterConfig;
      uint32_t sourceClock;
      i2c_master_transfer_t masterXfer;
  
      BOARD_InitPins();
      BOARD_BootClockRUN();
      BOARD_InitDebugConsole();
  
      PRINTF("\r\nI2C board2board interrupt example -- Master transfer.\r\n");
  
      /* Set up i2c master to send data to slave*/
      /* First data in txBuff is data length of the transmiting data. */
      g_master_txBuff[0] = I2C_DATA_LENGTH - 1U;
      for (uint32_t i = 1U; i < I2C_DATA_LENGTH; i++)
      {
          g_master_txBuff[i] = i - 1;
      }
  
      PRINTF("Master will send data :");
      for (uint32_t i = 0U; i < I2C_DATA_LENGTH - 1U; i++)
      {
          if (i % 8 == 0)
          {
              PRINTF("\r\n");
          }
          PRINTF("0x%2x  ", g_master_txBuff[i + 1]);
      }
      PRINTF("\r\n\r\n");
  
      /*
       * masterConfig->baudRate_Bps = 100000U;
       * masterConfig->enableStopHold = false;
       * masterConfig->glitchFilterWidth = 0U;
       * masterConfig->enableMaster = true;
       */
      I2C_MasterGetDefaultConfig(&masterConfig);
      masterConfig.baudRate_Bps = I2C_BAUDRATE;
  
      sourceClock = I2C_MASTER_CLK_FREQ;
  
      I2C_MasterInit(EXAMPLE_I2C_MASTER_BASEADDR, &masterConfig, sourceClock);
  
      memset(&g_m_handle, 0, sizeof(g_m_handle));
      memset(&masterXfer, 0, sizeof(masterXfer));
  
      /* subAddress = 0x01, data = g_master_txBuff - write to slave.
        start + slaveaddress(w) + subAddress + length of data buffer + data buffer + stop*/
      uint8_t deviceAddress     = 0x01U;
      masterXfer.slaveAddress   = I2C_MASTER_SLAVE_ADDR_7BIT;
      masterXfer.direction      = kI2C_Write;
      masterXfer.subaddress     = (uint32_t)deviceAddress;
      masterXfer.subaddressSize = 1;
      masterXfer.data           = g_master_txBuff;
      masterXfer.dataSize       = I2C_DATA_LENGTH;
      masterXfer.flags          = kI2C_TransferDefaultFlag;
  
      I2C_MasterTransferCreateHandle(EXAMPLE_I2C_MASTER_BASEADDR, &g_m_handle, i2c_master_callback, NULL);
      I2C_MasterTransferNonBlocking(EXAMPLE_I2C_MASTER_BASEADDR, &g_m_handle, &masterXfer);
  
      /*  Wait for transfer completed. */
      while (!g_MasterCompletionFlag)
      {
      }
      g_MasterCompletionFlag = false;
  
      PRINTF("Receive sent data from slave :");
  
      /* subAddress = 0x01, data = g_master_rxBuff - read from slave.
        start + slaveaddress(w) + subAddress + repeated start + slaveaddress(r) + rx data buffer + stop */
      masterXfer.slaveAddress   = I2C_MASTER_SLAVE_ADDR_7BIT;
      masterXfer.direction      = kI2C_Read;
      masterXfer.subaddress     = (uint32_t)deviceAddress;
      masterXfer.subaddressSize = 1;
      masterXfer.data           = g_master_rxBuff;
      masterXfer.dataSize       = I2C_DATA_LENGTH - 1;
      masterXfer.flags          = kI2C_TransferDefaultFlag;
  
      I2C_MasterTransferNonBlocking(EXAMPLE_I2C_MASTER_BASEADDR, &g_m_handle, &masterXfer);
  
      /*  Reset master completion flag to false. */
      g_MasterCompletionFlag = false;
  
      /*  Wait for transfer completed. */
      while (!g_MasterCompletionFlag)
      {
      }
      g_MasterCompletionFlag = false;
  
      for (uint32_t i = 0U; i < I2C_DATA_LENGTH - 1; i++)
      {
          if (i % 8 == 0)
          {
              PRINTF("\r\n");
          }
          PRINTF("0x%2x  ", g_master_rxBuff[i]);
      }
      PRINTF("\r\n\r\n");
  
      /* Transfer completed. Check the data.*/
      for (uint32_t i = 0U; i < I2C_DATA_LENGTH - 1; i++)
      {
          if (g_master_rxBuff[i] != g_master_txBuff[i + 1])
          {
              PRINTF("\r\nError occurred in the transfer ! \r\n");
              break;
          }
      }
  
      PRINTF("\r\nEnd of I2C example .\r\n");
      while (1)
      {
      }
  }
  