migrating code from MSP430F1232 on earlier IAR compiler to MSP430F2132 with latest IAR compiler

It's not as easy to migrate from 1x to 2x. Some parts are identical or at least backwards compatible (ports and timers, even the ADCs), some things are different, like the migration form USART to USCI. One of the differences, IIRC, is that the USART has edge-triggered interrupts, the USCi has level-triggered interrupts. So if you don't clear the IFG bit that caused an interrupts (e.g. by reading RXBUF to clear RXIFG, or by manually resetting it), you'll go into an endless interrupt loop.
Also, there are a lot more interrupt souces than before.

However, your description of an endless resets rather looks liek you have enabled an interrupt but didn't write an ISR for it.
Perhaps a mistake in the naming of the timer vectors?

I had to take a look at your code to check it. (you can send it in a private conversation if you don't want to post it in the public, but provide a link to this thread so I can answer here)

Thanks very much for the response.  Using the dis-assembly listing I have verified that the interrupt vectors actually point to the service routines so below are segments of the code that should show what I'm doing wrong!

unsigned int Flag = 0, Nominal = 999;
unsigned int ThermV = 0, Supply = 0, Illum = 0;
unsigned int Sample, Previous = 512, PrevPrev = 512, PrevPrevPrev = 512;
unsigned int SumP2P = 0, Max = 0, Min = 512;
unsigned int Ticks = 0, Intensity = 0, Sum4 = 0, Peak = 0;
unsigned int Dividend, Divisor, Quotient, Mask;
unsigned int Interrupts = 0, Span = 0, Digit = 0;
unsigned int Degrees = 0, Decimal = 0, Minutes = 0, Remainder = 0;
unsigned int RxPtr = 0, TxPtr = 0, ProcPtr = 0, LoadPtr = 31 ;
unsigned int Factor = 0;

char ZeroXptr = 0, Bright = 0, Count = 0, Sixths = 0, Trend = 127;
char Top, Step, Index = 0, VoltsCode, VoltsUnits, VoltsDeci;
char Temp = 0, Samples = 0, CharCount = 0, SampleCount = 0;
char Plot[54] ;
char RxBuf[8]= "       ";
char TxBuff[32]= "  Sign-on message goes here     ";
int Write(int);
char Put(); // puts individual characters into the output buffer
void Graph(); // plot the beam strength distribution

void main(void)
{
  void Init_Micro();
  Init_Micro();

  void Divide();  // Calculates a scaling factor at start-up
 // void ApplyScale();
  void Report();
  void Show();  // Generates the graphic plot
  void ShowV(); // Displays the raw supply voltage
  void ShowT(); // Displays temperature degrees C
  void Clock(); // A simple minutes of month clock
  IE2 |= (UCA0RXIE + UCA0TXIE); // Enable UART Rx & Tx interrupts
  IE2 &= 0xF3; // Disable other UART interrupts
  IFG2 &= ~UCB0TXIFG;
  TxBuff[29] = CR; TxBuff[30] = LF;
  _EINT(); // Enable global interrupts
  IFG2 |= UCA0TXIFG; // Trigger the Sign on message
  Flag |= Finished;
  for (;;) // Keep executing this loop while awaiting interrupts
    {
     if(P2IN & IN1) // Switch 1 in Running mode?

..........................

void Setup_Ports()
{
  // bit0 = Relay, bit1 = LED1, bit2 = PWM, bit3 = LED 2
  // bit4 = Tamper, bit5 = SW1, bit6 = SW2, bit7 = Sample
  P1SEL |= 0x04; // bit2 assigned to PWM, all others to pins
  P1SEL2 &= 0x04; //(Bit2 is set to primary periferal)
  P1REN = 0x00; // No pullups
  P1DIR |= 0x8F; // LEDs 1 & 2 + relay output + switches in.
  P1OUT &= ~(LED1 + LED2 + Relay); // Initialise LED display
  // bit 0 = Temp, bit 1 = Opto, bit 2 = V_panel, bit 3 = V_Charger
  // bit 4 = V_Bat.
  P2SEL |= 0xC0; // LO 5 bits to ADC.
  P2SEL2 &= 0xC0;
  P1REN &= 0x00; // No pullups
  P2DIR &= 0x00; // all bits are inputs.
  // bit0 = LDR, bit1 = Config, bit2 = Reg_En, bit3 = RS232_Status
  // bit4 = UART_TX, bit5 = UART_RX, bit6 = Ring_Indic, bit7 = RS232_En
  P3SEL |= 0x30; // bits 4 & 5 = UART I/O, bit 0 = ADC(LDR)
  P3DIR |= 0x84; // bits 7,6,4 & 2 are outputs
  P3OUT |= Serial_En; // turn the RS232 chip output ON.
} // end of Setup_Ports
void Setup_UART()
{
  // Now set up the UART, NOTE THAT THIS DIFFERS FROM 1232
  UCA0CTL1 |= UCSWRST; // Hold the hardware in Reset during setup.
  UCA0CTL0 |= UC7BIT;
  UCA0CTL1 |= UCSSEL_1; // Set main clock.
  UCA0BR0 = 0xA1; // Divide 4mHz Clock by 417 for Baud rate = 9600
  UCA0BR1 = 0x01 ;
  UCA0MCTL = 0x00; // No modulation of the clock
  IE2 |= UCA0TXIE + UCA0RXIE; // Enable UART for Rx & Tx.
  UCA0CTL1 &= ~UCSWRST; // Remove the hardware reset and allow operation.
} // end of setup UART

.................

#pragma vector = USCIAB0RX_VECTOR
__interrupt void asart0rx(void)
{
  char Temp;
  if(IFG2 & UCA0RXIFG) // UART Rx interrupt?
     {
      Temp = UCA0RXBUF; // Yes, read character.
      RxBuf[RxPtr++] = Temp; // Save it to buffer.
      if(RxPtr > 31)
         RxPtr = 0; // circular buffer.
      if(Temp == CR)
        Flag |= Reply;
      else
        Flag &= ~Reply;
      if(Temp == Question)
        Flag |= Distrib;
      else
        Flag &= ~Distrib;
     }
}  // end of serial receive code

#pragma vector = USCIAB0TX_VECTOR
__interrupt void usart0tx(void)
{
 if(IFG2 & UCA0TXIFG) // UART Tx Interrupt?
  {
   if(TxPtr != LoadPtr)
     {
       UCA0TXBUF = TxBuff[TxPtr++];
       if(TxPtr > 31)
         TxPtr = 0; // Circular buffer.
       if(CharCount > 0) // Keep track of buffer capacity
          CharCount--;
     }
   else
     Flag |= Finished;
   IFG2 &= ~UCA0TXIFG;
  }
} // end of serial transmit interrupt

Thanks again

Jens, Further testing has revealed the true nature of my problem.  It seems that I didn't check  TimerA for differences as the compiler didn't object to anything.  However, as you suggested in your initial response, it looked like I had an interrupt without an ISR to service it.  I also have a Real Time Clock based on TimerA & after turning all the other interrupts off one by one studying the documentation I spotted the problem and corrected the code.  I had called the interrupt vector TIMER0_A1  VECTOR instead of the TIMER0_A0 VECTOR  that I was trying to use.  I'm not sure yet if this was a typo or a difference between this chip and the earlier '1232.   Either way I can now re-enable the serial interrupts and get on with debugging the rest of the code.

Thank you for focussing my attention on what should have been obvious to me!  I hope you haven't spent too much time looking at this.

Regards,

Graham