Hi
i'm using the msp430f1612 with IAR kickstart compiler. at moment i
am just trying to get the comms working on uart 0.
sending data is fine. but receiveing data is not.
basicaly i have an interrupt routine for the uart RX.
When i type a character on the hyperterminal, the program jumps into
the RX interrupt and echoes back the received caharacter, however
the program does not exit the interrupt, and instead it keeps
looping through the routine, the result is that the single character
received is continulsly transmitted back to the interrupt. i do not
know what the problem is.

this is the interrupt code

#pragma vector = UART0RX_VECTOR
__interrupt void UART_0_RX_isr(void)
{
char Temp;
Temp = U0RXBUF;
while (!(IFG1 & UTXIFG0));
U0TXBUF = Temp;
}

looking at the registers, i see that URXIFG0 flag is cleared when
the interrupt is processed, the flag remains clear, but yet the
interrupt is being continuosly called. it is as if the the stack has
been modified, to jump back to interrupt vector when the interrupt
exits.
Any Ideas?

Hello ,
  show this:
   
  #pragma vector = UART0RX_VECTOR
__interrupt void UART_0_RX_isr(void)
{
char Temp;
Temp = U0RXBUF;
/*
  while (!(IFG1 & UTXIFG0));
*/
  IFG1 &= ~URXIFG0;               // Receive interrupt flag reset
ME1 &= ~URXE0;                  // UART-RX disable
   
  ME1 |= UTXE0;     // TX enable
  U0TXBUF = Temp;
}
#pragma vector = UART0TX_VECTOR
__interrupt void UART_0_TX_isr(void)
{
        U0TXBUF = Temp;

          ME1 &= ~UTXE0;              // 
           ME1 |= URXE0;               // 
        IFG1 &= ~URXIFG0;           //
}

piercebrady <piercebrady@pier...> schrieb:
  Hi
i'm using the msp430f1612 with IAR kickstart compiler. at moment i
am just trying to get the comms working on uart 0.
sending data is fine. but receiveing data is not.
basicaly i have an interrupt routine for the uart RX.
When i type a character on the hyperterminal, the program jumps into
the RX interrupt and echoes back the received caharacter, however
the program does not exit the interrupt, and instead it keeps
looping through the routine, the result is that the single character
received is continulsly transmitted back to the interrupt. i do not
know what the problem is.

this is the interrupt code

#pragma vector = UART0RX_VECTOR
__interrupt void UART_0_RX_isr(void)
{
char Temp;
Temp = U0RXBUF;
while (!(IFG1 & UTXIFG0));
U0TXBUF = Temp;
}

looking at the registers, i see that URXIFG0 flag is cleared when
the interrupt is processed, the flag remains clear, but yet the
interrupt is being continuosly called. it is as if the the stack has
been modified, to jump back to interrupt vector when the interrupt
exits.
Any Ideas?





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>From: piercebrady <piercebrady@pier...>
>Subject: [msp430] Trapped in UART interrupt
[snip]
>basicaly i have an interrupt routine for the uart
RX.
>When i type a character on the hyperterminal, the program jumps into
>the RX interrupt and echoes back the received caharacter, however
>the program does not exit the interrupt, and instead it keeps
>looping through the routine, the result is that the single character
>received is continulsly transmitted back to the interrupt. i do not
>know what the problem is.
>
>this is the interrupt code
>
>#pragma vector = UART0RX_VECTOR
>__interrupt void UART_0_RX_isr(void)
>{
>char Temp;
>Temp = U0RXBUF;
>while (!(IFG1 & UTXIFG0));
>U0TXBUF = Temp;
>}
>
[snip]
>Any Ideas?


Pierce,

No other people jumping in, so I'll offer an idea...

Is your hyperterminal set up for full duplex? I.e., is your terminal echoing
what it receives and you have two units talking back and forth? 

Another possibility is if you have the processor set to respond to receive
start-edge detection. In this case, the processor can get started and respond to
the UART even when it is in LPM mode.

In this case, you need to monitor URXIFGx. if it is 0, you need to wait. when it
goes high, the buffer has valid data and can be read - See the section of the
User's Manual titled "Receive-Start Edge Detect Operation" (pg
13-19 of slau049e.pdf).

Just something to check...

Let us know how things work out.

Rachel
Norristown, PA, USA