I2C communication with I2C_EV interrupts

[nanayakkaraan]

Posted on December 23, 2010 at 10:31

I2C communication with I2C_EV interrupts

[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

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,

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 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

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,

Still it doesnot read. Same problem persist :(

[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.