how to use 2UART & 1I2C same time & write single interrupt to handle both peripherals(UART & I2C) MSP430F2617

Hi Utpal,

you can check for the pending flags inside the ISRs:

#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR
{
  if( IFG2 & UCA0TXIFG )
  {
    // Do something for USCI_A0 UART TX
  }
  else if( IFG2 & UCB0TXIFG )
  {
    // Do something for USCI_B0 I2C TX
  }
}

#pragma vector = USCIAB0RX_VECTOR
__interrupt void USCIAB0RX_ISR
{
  if( IFG2 & UCA0RXIFG )
  {
    // Do something for USCI_A0 UART RX
  }
  else if( IFG2 & UCB0RXIFG )
  {
    // Do something for USCI_B0 I2C RX
  }
}

#pragma vector = USCIAB1TX_VECTOR
__interrupt void USCIAB1TX_ISR
{
  if( UC1IFG & UCA1TXIFG )
  {
    // Do something for USCI_A1 UART TX
  }
  else if( UC1IFG & UCB1TXIFG )
  {
    // Do something for USCI_B1 I2C TX
  }
}

#pragma vector = USCIAB1RX_VECTOR
__interrupt void USCIAB1RX_ISR
{
  if( UC1IFG & UCA1RXIFG )
  {
    // Do something for USCI_A1 UART RX
  }
  else if( UC1IFG & UCB1RXIFG )
  {
    // Do something for USCI_B1 I2C RX
  }
}

Dennis

Hi,
Thanks for your quick response .
Please help me to resolve my doubt.

#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR
{
if( IFG2 & UCA0TXIFG )
{
// Do something for USCI_A0 UART TX
}
else if( IFG2 & UCB0TXIFG )
{
// Do something for USCI_B0 I2C TX
}
}

In above code what will happens if I2C connected to UCB0TXIFG & UART connected to UCA0TXIFG initialize the sending of data at the same time.
Is there any possibility that transmission data will get missed.as UART operate on baud rate (timings) & if its interrupt is pending due to I2C work.
Please clarify.

Regards,
utpal

The other interrupt flag stays set and will be serviced afterwards. Of course the interrrupt service routine has to be short enough to handle the other interrupt before another interrupt is generated for the source you did not even finish, otherwise you will loose interrrupt requests.

You could change the code to the following as well:

#pragma vector = USCIAB0TX_VECTOR
__interrupt void USCIAB0TX_ISR
{
  if( IFG2 & UCA0TXIFG )
  {
    // Do something for USCI_A0 UART TX
  }
  
  if( IFG2 & UCB0TXIFG )
  {
    // Do something for USCI_B0 I2C TX
  }
}

In this case both sources are checked in one interrupt service routine call. This will shorten the time if both flags are set, but the ISR takes longer if they are not.

Dennis