i2c.c

#include "main.h"

#include <stm32f4xx.h>

#include <stm32f4xx_i2c.h>

#include "i2c.h"

//-------------------------------------------

// Definition of local constants

//-------------------------------------------

#define I2C_TIMEOUT  (0x1000)

//-------------------------------------------

// Declaration of local functions

//-------------------------------------------

static int I2C_check_dev(uint8_t addr);

static int I2C_start(I2C_TypeDef* I2Cx, uint8_t addr, uint8_t rdwr);

static int I2C_restart(I2C_TypeDef* I2Cx, uint8_t addr, uint8_t rdwr);

static int I2C_stop(I2C_TypeDef* I2Cx);

static int I2C_write(I2C_TypeDef* I2Cx, uint8_t data);

static int I2C_read_ack(I2C_TypeDef* I2Cx);

static int I2C_read_nack(I2C_TypeDef* I2Cx);

static int I2C_timeout(char *msg);

/*******************************************************************************

* Function Name  : I2C_BusInit

* Description    : Configure I2C-Bus

* Input          : None

* Output         : None

* Return         : None

* Attention       : None

*******************************************************************************/

void I2C_BusInit(void)

{                         

  GPIO_InitTypeDef GPIO_InitStructure;

  I2C_InitTypeDef  I2C_InitStructure;

  //NVIC_InitTypeDef NVIC_InitStructure;

  //=========================================================================================

  // Enable GPIO clock

  //-----------------------------------------------------------------------------------------

  RCC_AHB1PeriphClockCmd(Open_I2C_SCL_GPIO_CLK, ENABLE);

  //=========================================================================================

  // Enable I2C clock

  //-----------------------------------------------------------------------------------------

  RCC_APB1PeriphClockCmd(Open_I2C_CLK, ENABLE);

  //=========================================================================================

  //GPIO Alternate functions configuration

  //-----------------------------------------------------------------------------------------

  GPIO_PinAFConfig(Open_I2C_SCL_GPIO_PORT, Open_I2C_SCL_SOURCE, Open_I2C_SCL_AF);

  GPIO_PinAFConfig(Open_I2C_SDA_GPIO_PORT, Open_I2C_SDA_SOURCE, Open_I2C_SDA_AF);

  //=========================================================================================

  // Configure I2C GPIO

  //-----------------------------------------------------------------------------------------

  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin = Open_I2C_SCL_PIN | Open_I2C_SDA_PIN;

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOB, &GPIO_InitStructure);

  //=========================================================================================

  // Configure I2C Controller

  //-----------------------------------------------------------------------------------------

  I2C_InitStructure.I2C_ClockSpeed = I2C_SCL_SPEED;

  I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

  I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

  I2C_InitStructure.I2C_OwnAddress1 = I2C_OWN_ADDR;

  I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

  I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

  //=========================================================================================

  // Enable I2C

  //-----------------------------------------------------------------------------------------

  I2C_Cmd(Open_I2C, ENABLE);

  I2C_Init(Open_I2C, &I2C_InitStructure);

  //=========================================================================================

  // Configure the SPI interrupt priority

  //-----------------------------------------------------------------------------------------

  /*

  NVIC_InitStructure.NVIC_IRQChannel = Open_I2C_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

  */

}

//===============================================================================

// I2C_ReadTransfer - initiate a read transfer on the I2C bus

//

// Initiates a read transfer on the I2C bus.

// If a register address is specified (<addressLength> != 0) a write without a stop

// condition will be initiated to the device to write the address, before the

// read is initiated.

// If no address if required (sequential read) <addressLength> is set to 0.

//-------------------------------------------------------------------------------

// u08 dev_addr  I2C device address

// u08 *buffer   pointer to the buffer to store the read data.

//               The buffer must be at least 'cnt' bytes long

// int cnt       number of bytes to read

// u32 ptr       register address, if required by the I2C-device

// u08 ptrlen    length of the register address to be written.

//               Valid values are 0..4

//-------------------------------------------------------------------------------

int I2C_ReadTransfer(uint8_t dev_addr, uint8_t *buffer, int cnt, uint32_t ptr, uint8_t ptrlen)

{

  int i, rc = OK;

  //-----------------------------------------------------------------------------

  // parameter check

  //-----------------------------------------------------------------------------

  if ((buffer == 0) || (ptrlen > 4) || ((cnt | ptrlen) == 0))

  {

    return I2C_check_dev(dev_addr); // may be used to check if device is responding

  }

  //-----------------------------------------------------------------------------

  // write the register address pointer to the device

  //-----------------------------------------------------------------------------

  if (ptrlen > 0)

  {

    rc = I2C_start(Open_I2C, dev_addr, I2C_Direction_Transmitter);

    if (rc == OK)

    {

      for (i=1; i<=ptrlen; i++)

      {

        rc |= I2C_write(Open_I2C,((ptr >>(8*(ptrlen-i))) & 0xff));

      }

    }

  }

  //-----------------------------------------------------------------------------

  // read data from device

  //-----------------------------------------------------------------------------

  if ((cnt > 0) && (rc == OK))

  {

    if (ptrlen > 0)

    {

      rc |= I2C_restart(Open_I2C, dev_addr, I2C_Direction_Receiver);

    }

    else

    {

      rc |= I2C_start(Open_I2C, dev_addr, I2C_Direction_Receiver);

    }

    if (rc == OK)

    {

      while (--cnt>0)                         // while more than one byte to read

      {

        *(buffer++) = I2C_read_ack(Open_I2C); // read next databyte from I2C device

      }

      *(buffer) = I2C_read_nack(Open_I2C);    // read last databyte from I2C device

    }

  }

  //-----------------------------------------------------------------------------

  I2C_stop(Open_I2C);                         // stop the transmission

  return rc;

}

//===============================================================================

// I2C_WriteTransfer r- initiate a write transfer on the I2C bus

//

// Initiates a write transfer on the I2C bus.

// If a register address is supplied it is inserted between the I2C device address

// and the data.

//-------------------------------------------------------------------------------

// u08 dev_addr  I2C device address

// u08 *buffer   pointer to the buffer to store the read data.

//               The buffer must be at least 'cnt' bytes long

// int cnt       number of bytes to read

// u32 ptr       register address, if required by the I2C-device

// u08 ptrlen    length of the register address to be written.

//               Valid values are 0..4

//-------------------------------------------------------------------------------

int  I2C_WriteTransfer(uint8_t dev_addr, uint8_t *buffer, int cnt, uint32_t ptr, uint8_t ptrlen)

{

  int i, rc=OK;

  //-----------------------------------------------------------------------------

  // parameter check

  //-----------------------------------------------------------------------------

  if ((buffer == 0) || (ptrlen > 4) || ((cnt | ptrlen) == 0))

  {

    return I2C_check_dev(dev_addr); // may be used to check if device is responding

  }

  //-----------------------------------------------------------------------------

  rc = I2C_start(Open_I2C, dev_addr, I2C_Direction_Transmitter);

  if (rc == OK)

  {

    //---------------------------------------------------------------------------

    // write the register address pointer to the device

    //---------------------------------------------------------------------------

    if (ptrlen > 0)

    {

      for (i=1; i<=ptrlen; i++)

      {

        rc |= I2C_write(Open_I2C,((ptr >>(8*(ptrlen-i))) & 0xff));

      }

    }

    //---------------------------------------------------------------------------

    // write data to the device

    //---------------------------------------------------------------------------

    for (i=0; i<cnt; i++)

    {

      rc |= I2C_write(Open_I2C,*(buffer++));

    }

  }

  //-----------------------------------------------------------------------------

  I2C_stop(Open_I2C);                // stop the transmission

  return rc;

}

//===============================================================================

// Check if a device is responding with acknowledge on the given I2C-Bus address

//-------------------------------------------------------------------------------

static int I2C_check_dev(uint8_t addr)

{

  int timeout;

  //-----------------------------------------------------------------------------

  timeout = I2C_TIMEOUT;

  while(I2C_GetFlagStatus(Open_I2C, I2C_FLAG_BUSY))

  {

    if((timeout--)==0)   // wait until I2C-Bus is not busy anymore

    {

      return ERROR;

    }

  }

  //-----------------------------------------------------------------------------

  I2C_GenerateSTART(Open_I2C, ENABLE);

  timeout = I2C_TIMEOUT;

  while(!I2C_CheckEvent(Open_I2C, I2C_EVENT_MASTER_MODE_SELECT))

  {

    if((timeout--)==0)  // wait while sending I2C-Bus START condition

    {

      I2C_GenerateSTOP(Open_I2C, ENABLE);

      return ERROR;

    }

  }

  //-----------------------------------------------------------------------------

  I2C_Send7bitAddress(Open_I2C, addr, I2C_Direction_Transmitter);

  timeout = I2C_TIMEOUT;

  while(!I2C_CheckEvent(Open_I2C, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))

  {

    if((timeout--)==0)   // wait while sending slave address for write

    {

      I2C_GenerateSTOP(Open_I2C, ENABLE);

      return ERROR;

    }

  }

  //-----------------------------------------------------------------------------

  I2C_GenerateSTOP(Open_I2C, ENABLE);

  return OK;

}

//------------------------------------------------------------------

// This function issues a start condition and

// transmits the slave address + R/W bit

//

// Parameters:

//  I2Cx  --> the I2C peripheral e.g. I2C1

//  addr  --> the 7 bit slave address

//  rdwr  --> the tranmission direction can be:

//              I2C_Direction_Tranmitter for Master transmitter mode

//              I2C_Direction_Receiver for Master receiver

//------------------------------------------------------------------

static int I2C_start(I2C_TypeDef* I2Cx, uint8_t addr, uint8_t rdwr)

{

  uint32_t timeout = (100 * I2C_TIMEOUT);

  // wait until I2C1 is not busy anymore

  while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY))

  {

    if((timeout--)==0) return I2C_timeout("I2C_start(): bus busy");

  }

  // Send I2C1 RESTART condition

  return I2C_restart(I2Cx, addr, rdwr);

}

//------------------------------------------------------------------

// This function issues a restart condition and

// transmits the slave address + R/W bit

//

// Parameters:

//  I2Cx  --> the I2C peripheral e.g. I2C1

//  addr  --> the 7 bit slave address

//  rdwr  --> the tranmission direction can be:

//              I2C_Direction_Tranmitter for Master transmitter mode

//              I2C_Direction_Receiver for Master receiver

//------------------------------------------------------------------

static int I2C_restart(I2C_TypeDef* I2Cx, uint8_t addr, uint8_t rdwr)

{

  uint32_t timeout = I2C_TIMEOUT;

  // Send I2C1 START condition

  I2C_GenerateSTART(I2Cx, ENABLE);

  // wait for I2C1 EV5 --> Slave has acknowledged start condition

  while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT))

  {

    if((timeout--)==0) return I2C_timeout("I2C_start(): start failed");

  }

  // Send slave Address for read or write

  I2C_Send7bitAddress(I2Cx, addr, rdwr);

  //------------------------------------------------------------------------

  // wait for I2C1 EV6, check if Slave has acknowledged Master transmitter

  // or Master receiver mode, depending on the transmission direction

  //------------------------------------------------------------------------

  timeout = I2C_TIMEOUT;

  if (rdwr==I2C_Direction_Transmitter)

  {

    while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))

    {

      if((timeout--)==0) return I2C_timeout("I2C_start(): no acknowledge");

    }

  }

  else if(rdwr==I2C_Direction_Receiver)

  {

    while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))

    {

      if((timeout--)==0) return I2C_timeout("I2C_start(): no acknowledge");

    }

  }

  return 0;

}

//------------------------------------------------------------------

// This function transmits one byte to the slave device

// Parameters:

//    I2Cx --> the I2C peripheral e.g. I2C1

//    data --> the data byte to be transmitted

//------------------------------------------------------------------

static int I2C_write(I2C_TypeDef* I2Cx, uint8_t data)

{

  uint32_t timeout = I2C_TIMEOUT;

  I2C_SendData(I2Cx, data);

  // wait for I2C1 EV8_2 --> byte has been transmitted

  while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED))

  {

    if((timeout--)==0) return I2C_timeout("I2C_write(): write byte failed");

  }

  return 0;

}

//------------------------------------------------------------------

// This function reads one byte from the slave device

// and acknowledges the byte (requests another byte)

//------------------------------------------------------------------

static int I2C_read_ack(I2C_TypeDef* I2Cx)

{

  uint32_t timeout = I2C_TIMEOUT;

  // enable acknowledge of recieved data

  I2C_AcknowledgeConfig(I2Cx, ENABLE);

  // wait until one byte has been received

  while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED))

  {

    if((timeout--)==0) return I2C_timeout("I2C_read_ack(): read byte failed");

  }

  // read data from I2C data register and return data byte

  return I2C_ReceiveData(I2Cx);

}

//------------------------------------------------------------------

// This function reads one byte from the slave device

// and doesn't acknowledge the recieved data

//------------------------------------------------------------------

static int I2C_read_nack(I2C_TypeDef* I2Cx)

{

  uint32_t timeout = I2C_TIMEOUT;

  // disabe acknowledge of received data

  I2C_AcknowledgeConfig(I2Cx, DISABLE);

  // wait until one byte has been received

  while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED))

  {

    if((timeout--)==0) return I2C_timeout("I2C_read_nack(): read byte failed");

  }

  // read data from I2C data register and return data byte

  return I2C_ReceiveData(I2Cx);

}

//------------------------------------------------------------------

// This funtion issues a stop condition and therefore

// releases the bus

//------------------------------------------------------------------

static int I2C_stop(I2C_TypeDef* I2Cx)

{

  // Send I2C1 STOP Condition

  I2C_GenerateSTOP(I2Cx, ENABLE);

  return 0;

}

static int I2C_timeout(char *msg)

{

  printf("TIMEOUT: %s\n",msg);

  return -1;

}

void I2C1_EV_IRQHandler(void)

{

  u32 event;

  event = I2C_GetLastEvent(I2C2);

  printf("I2C1_EV_IRQHandler(): Event=0x%08X\n",event);

  //---------------------------------------------------

  // todo, if I2C1 ISR mode shall be used

  //---------------------------------------------------

}

void I2C2_EV_IRQHandler(void)

{

  u32 event;

  event = I2C_GetLastEvent(I2C2);

  printf("I2C2_EV_IRQHandler(): Event=0x%08X\n",event);

  //---------------------------------------------------

  // todo, if I2C2 ISR mode shall be used

  //---------------------------------------------------

}