I2C communication with I2C_EV interrupts

[nanayakkaraan]

Posted on December 23, 2010 at 10:31

I2C communication with I2C_EV interrupts

[nanayakkaraan]

Posted on May 17, 2011 at 14:19

Thanks for the reply.

Here I am attaching my I2CEV IRQ handler function which does not give me the desired functionality.

What I want is to just read a 8 bit data at the given register address and it does not do that.

void I2C2_EV_IRQHandler(void)

{

 

  // Get Last I2C Event   

  Event = I2C_GetLastEvent(I2C2);

  switch (Event)

  {

  // EV5- 0x00030001 BUSY, MSL and RXNE flags

  case I2C_EVENT_MASTER_MODE_SELECT:

  {

    // Send I2C slave address for write

    I2C_Send7bitAddress(I2C2,I2C_read.u8SlaveAdd ,

                        I2C_read.u8I2CDir);

  }   

  break;  

 

  // EV6 - 0x00070082 BUSY, MSL, ADDR, TXE and TRA flags

  case I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED:

  {

  }

  break;

 

  // EV6 - 0x00030002 BUSY, MSL and ADDR flags

  case I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED:

  break;

 

  //EV7 - 0x00030040 BUSY, MSL and RXNE flags

  case I2C_EVENT_MASTER_BYTE_RECEIVED:

  {

      I2C_read.u16Reading = I2C_ReceiveData(I2C2) <<8;

    //Disable Acknowledgement

    I2C_AcknowledgeConfig(I2C2, DISABLE);

    //Generate Stop

    I2C_GenerateSTOP(I2C2,ENABLE);

  }

  break;

  // EV8(EV8_1)- 0x00070080 TRA, BUSY, MSL, TXE flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTING:

  {

    // Send read register address

    I2C_SendData(I2C2, I2C_read.u8RegAdd);

  } 

  break;

  

  // EV8_2(EV8)- 0x00070084 TRA, BUSY, MSL, TXE and BTF flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTED:

  {

    I2C_read.u8I2CDir = I2C_Direction_Receiver;

    //Generate a Restart condition

    I2C_GenerateSTART(I2C2,ENABLE);

  }

  default:

  break;

  }

}

Can anybody figure out where I am going wrong/ any idea to proceed with?

Thank you.

[mtaallah]

Posted on May 17, 2011 at 14:19

Hi,

** These steps should be done before starting I2C communication with Interrupt in main program :

1- Configure I2C :  Fill Init structure with adequate values

  e.g:

      /*!< I2C Struct Initialize */

  I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

  I2C_InitStructure.I2C_DutyCycle = I2C_DUTYCYCLE;

  I2C_InitStructure.I2C_OwnAddress1 = 0xA0;

  I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

  I2C_InitStructure.I2C_ClockSpeed = I2C_SPEED;

  I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

2- Call I2c_Init : 

  /*!< I2C Initialize */

  I2C_Init(I2Cx, &I2C_InitStructure);

  /* I2C ENABLE */

  I2C_Cmd(I2Cx, ENABLE);

  

3- Enable Interrupt :

  /* Enable Event and Buffer Interrupts */

  I2C_ITConfig(I2Cx, (I2C_IT_EVT | I2C_IT_BUF), ENABLE);

4- Generate start to start communication:

  /* Generate the Start condition */

  I2C_GenerateSTART(I2Cx, ENABLE);

 

** In stm32l1xx_it.c file you must implement  I2Cx Event IRQHANDLER:

 e.g: how to implement handler for master transmitter :

  void I2C1_EV_IRQHANDLER(void)

   {

      /* Get Last I2C Event */

      Event = I2C_GetLastEvent(I2C1);

   

      switch (Event)

       {

    

        /* Check on EV5 */

        case I2C_EVENT_MASTER_MODE_SELECT :

              /* Send slave Address for write */

              I2C_Send7bitAddress(I2C1, (uint8_t)SLAVE_ADDRESS, I2C_Direction_Transmitter);

        break;

     

     

        /* Check on EV6 */

        case I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED:

              /* Transmit the First Data  */

              I2C_SendData(I2C1, TxBuffer[Tx_Idx++]);

        break;

     

        /* Check on EV8 */

        case I2C_EVENT_MASTER_BYTE_TRANSMITTING:

              /* Transmit Data TxBuffer */

              I2C_SendData(I2C1, TxBuffer[Tx_Idx++]);

              if (Tx_Idx == (uint8_t)NumberOfByteToTransmit)

              {

                /* Send STOP condition */

                I2C_GenerateSTOP(I2C1, ENABLE);

                /* Disable the Transmit complete interrupt */

                I2C_ITConfig(I2C1, I2C_IT_BUF, DISABLE);;

              }

        break;

     

        default:

        

        break;

       }

   

    }

       

    TxBuffer : is the buffer that contains data to be transmitted

** If you want to handle i2c error you have to enable Error interrupt:*

        /* Enable Error Interrupt */

       I2C_ITConfig(I2Cx, I2C_IT_ERR , ENABLE);

  

   and implement Error IRQHANDLER

  

   void I2Cx_ER_IRQHANDLER(void)

    {    

      /* Read SR1 register to get I2C error */

      if ((I2C_ReadRegister(I2Cx, I2C_Register_SR1) & 0xFF00) != 0x00)

        {          

           /* you can add your code to monitor which error is

           occurred */

          

           /* Clears error flags */

           I2Cx->SR1 &= 0x00FF;

         }

     }

    

END.

    

          

          

          

          

          

[nanayakkaraan]

Posted on May 17, 2011 at 14:19

hello,

Still it does not work :(

As I see by debugging (am checking the value of Event) it is blocked between EV6 - 0x00070082 and EV8(EV8_1)- 0x00070080.

because the Event variable value is 0x00070082 and SR1 and SR 2 values corresponds to 0x00070080 (which means the value of Event at the next run is 0x00070080).

Any suggestion to overcome the issue?

Thank you.

[mtaallah]

Posted on May 17, 2011 at 14:19

Hi,

you will find as follow how to read 1byte:

void I2C2_EV_IRQHandler(void)

{

 

  // Get Last I2C Event   

  Event = I2C_GetLastEvent(I2C2);

  switch (Event)

  {

  // EV5- 0x00030001 BUSY, MSL and SB flags

  case I2C_EVENT_MASTER_MODE_SELECT:

  {

    // Send I2C slave address for write

    I2C_Send7bitAddress(I2C2,I2C_read.u8SlaveAdd ,

                        I2C_read.u8I2CDir);

  }   

  break;  

 

  // EV6 - 0x00070082 BUSY, MSL, ADDR, TXE and TRA flags

  case I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED:

  {

 

  }

  break;

 

  // EV6 - 0x00030002 BUSY, MSL and ADDR flags

  case I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED:

  {

   //Disable Acknowledgement

    I2C_AcknowledgeConfig(I2C2, DISABLE);

    //Generate Stop

    I2C_GenerateSTOP(I2C2,ENABLE);

  }

  break;

 

  //EV7 - 0x00030040 BUSY, MSL and RXNE flags

  case I2C_EVENT_MASTER_BYTE_RECEIVED:

  {

      I2C_read.u16Reading = I2C_ReceiveData(I2C2) <<8;

  

  }

  break;

  // EV8(EV8_1)- 0x00070080 TRA, BUSY, MSL, TXE flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTING:

  {

    // Send read register address

    I2C_SendData(I2C2, I2C_read.u8RegAdd);

  } 

  break;

  

  // EV8_2(EV8)- 0x00070084 TRA, BUSY, MSL, TXE and BTF flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTED:

  {

    I2C_read.u8I2CDir = I2C_Direction_Receiver;

    //Generate a Restart condition

    I2C_GenerateSTART(I2C2,ENABLE);

  }

  default:

  break;

  }

}

[nanayakkaraan]

Posted on May 17, 2011 at 14:19

Hello,

Still it doesnot read.

Same problem persist :(

[mtaallah]

Posted on May 17, 2011 at 14:19

I corrected the code.

I made an error in the previous post.

please test with the new code and tell me if it's ok.

void I2C2_EV_IRQHandler(void)

{ 

  // Get Last I2C Event   

  Event = I2C_GetLastEvent(I2C2);

  switch (Event)

  {

    // EV5- 0x00030001 BUSY, MSL and SB flags

  case I2C_EVENT_MASTER_MODE_SELECT:

    {

      // Send I2C slave address for write

      I2C_Send7bitAddress(I2C2,I2C_read.u8SlaveAdd ,

                          I2C_read.u8I2CDir);

    }   

    break;  

   

    // EV6 - 0x00070082 BUSY, MSL, ADDR, TXE and TRA flags

  case I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED:

    {

      // Send read register address

      I2C_SendData(I2C2, I2C_read.u8RegAdd);

    }

    break;

   

    // EV8(EV8_1)- 0x00070080 TRA, BUSY, MSL, TXE flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTING:

    {

      I2C_read.u8I2CDir = I2C_Direction_Receiver;

      //Generate a Restart condition

      I2C_GenerateSTART(I2C2,ENABLE);

    } 

    break;

   

    // EV6 - 0x00030002 BUSY, MSL and ADDR flags

  case I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED:

    {

      //Disable Acknowledgement

      I2C_AcknowledgeConfig(I2C2, DISABLE);

      //Generate Stop

      I2C_GenerateSTOP(I2C2,ENABLE);

    }

    break;

   

    //EV7 - 0x00030040 BUSY, MSL and RXNE flags

  case I2C_EVENT_MASTER_BYTE_RECEIVED:

    {

      I2C_read.u16Reading = I2C_ReceiveData(I2C2) <<8;

     

    }

    break;

       

  default:

    break;

  }

}

[nanayakkaraan]

Posted on May 17, 2011 at 14:19

Hello all,

I will be glad if somebody can help me.

When my I2C_Ev ISR is the following I2C data can be read.

///////////////////////////////////////////////////////////////////////////////////////

void I2C2_EV_IRQHandler(void)

{

 

  //Disable I2CEV interrupts

  I2C_ITConfig(I2C2, I2C_IT_EVT, DISABLE);

 

   // Get Last I2C Event   

  Event = I2C_GetLastEvent(I2C2);

   //EV5- 0x00030001 BUSY, MSL and RXNE flags 

  while(!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT))

  {

  }

  //Send I2C slave address for write

  I2C_Send7bitAddress(I2C2,I2C_read.u8SlaveAdd ,I2C_read.u8I2CDir);

  //EV6 - 0x00070082 BUSY, MSL, ADDR, TXE and TRA flags

   while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))

  {

  }

 

  //EV8(EV8_1)- 0x00070080 TRA, BUSY, MSL, TXE flags

  while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_BYTE_TRANSMITTING ))

  {

  }

 

  //Send read register address

  I2C_SendData(I2C2, I2C_read.u8RegAdd);

 

  //EV8_2(EV8)- 0x00070084 TRA, BUSY, MSL, TXE and BTF flags

   while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_BYTE_TRANSMITTED))

  {

  }

 

  //Reception

   I2C_read.u8I2CDir = I2C_Direction_Receiver;

 

  //Generate a Restart condition

  I2C_GenerateSTART(I2C2,ENABLE);

 

  //EV5- 0x00030001 BUSY, MSL and RXNE flags

  while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_MODE_SELECT))

  {

  }

 

  //Send I2C slave address for read

  I2C_Send7bitAddress(I2C2,I2C_read.u8SlaveAdd ,I2C_read.u8I2CDir);

 

  //EV6 - 0x00030002 BUSY, MSL and ADDR flags

  while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))

  {

  } 

 

  //EV7 - 0x00030040 BUSY, MSL and RXNE flags

  while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_BYTE_RECEIVED))

  {

  }

  I2C_read.u16Reading = I2C_ReceiveData(I2C2) <<8;

 

  //Disable Acknowledgement

  I2C_AcknowledgeConfig(I2C2, DISABLE);

  //Generate Stop

  I2C_GenerateSTOP(I2C2,ENABLE);

    while(!(I2C_GetFlagStatus(I2C2, I2C_FLAG_RXNE)))

  {}

  I2C_read.u16Reading |= I2C_ReceiveData(I2C2);

}

/////////////////////////////////////////////////////////////////////////////////////////////////////

but if I change the I2C_EV ISR to the following it does not work.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

void I2C2_EV_IRQHandler(void)

{

  // Get Last I2C Event   

  Event = I2C_GetLastEvent(I2C2);

  switch (Event)

  {

  // EV5- 0x00030001 BUSY, MSL and RXNE flags

  case I2C_EVENT_MASTER_MODE_SELECT:

  { 

    // Send I2C slave address for write

    I2C_Send7bitAddress(I2C2,I2C_read.u8SlaveAdd ,

                        I2C_read.u8I2CDir);

  }   

  break;  

 

  // EV6 - 0x00070082 BUSY, MSL, ADDR, TXE and TRA flags

  case I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED:

  {

    // Send read register address

    I2C_SendData(I2C2, I2C_read.u8RegAdd);

  }

  break;

 

  // EV6 - 0x00030002 BUSY, MSL and ADDR flags

  case I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED:

  break;

 

  //EV7 - 0x00030040 BUSY, MSL and RXNE flags

  case I2C_EVENT_MASTER_BYTE_RECEIVED:

  {

    I2C_read.u16Reading = I2C_ReceiveData(I2C2) <<8;

    //Disable Acknowledgement

    I2C_AcknowledgeConfig(I2C2, DISABLE);

    //Generate Stop

    I2C_GenerateSTOP(I2C2,ENABLE);

    while(!(I2C_GetFlagStatus(I2C2, I2C_FLAG_RXNE)))

    {}

    I2C_read.u16Reading |= I2C_ReceiveData(I2C2);

 

  }

  break;

  // EV8(EV8_1)- 0x00070080 TRA, BUSY, MSL, TXE flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTING:

  {

   } 

  break;

  

  // EV8_2(EV8)- 0x00070084 TRA, BUSY, MSL, TXE and BTF flags

  case I2C_EVENT_MASTER_BYTE_TRANSMITTED:

  {

    I2C_read.u8I2CDir = I2C_Direction_Receiver;

    //Generate a Restart condition

    I2C_GenerateSTART(I2C2,ENABLE);

  }

  break;

  default:

  break;

  }

}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

In the second case I am expecting to get the I2C_EV interrupt at each time events are occurring. As I notice only EV5 and EV 6 are captured and after that it gets trapped in somewhere in between EV6 and EV8_1.

As I understood both implementation are same.

When looking into St library files, both I2C_CheckEvent() and I2C_GetLastEvent() function has similar implementation.

If possible please let me know where I am going wrong and how to overcome this cumbersome issue.

Thank you.