Lpc2148 UART0 - code doesnt enter the interrupt handler

Question

Am using LPC2148 dev board and this is the code I have implemented

main() {
 initClock();
 initTimer0();

 led_init();  // init p0.21 
 rs232_init();

 while(1) {

 led_toggleState(); // toggle led
 delay(1000); // 1 sec delay

 }
}


void initTimer0() {
    T0CTCR = 0x0;   //Set Timer 0 into Timer Mode
    T0PR = 59999;   //Increment T0TC at every 60000 clock cycles
        //Count begins from zero hence subtracting 1
        //60000 clock cycles @60Mhz = 1 mS
    T0TCR = 0x02;   //Reset Timer
}

void initClock() {
  PLL0CON = 0x01;   //Enable PLL
  PLL0CFG = 0x24;   //Multiplier and divider setup
  PLL0FEED = 0xAA;  //Feed sequence
  PLL0FEED = 0x55;
  
  while(!(PLL0STAT & 0x00000400)); //is locked?
    
  PLL0CON = 0x03;   //Connect PLL after PLL is locked
  PLL0FEED = 0xAA;  //Feed sequence
  PLL0FEED = 0x55;
  VPBDIV = 0x01;    // PCLK is same as CCLK i.e.60 MHz
}

void rs232_init() {
    PINSEL0 = 0x05; // Enable UART0 pins
    U0LCR = 0x83; // 8-bit data, 1 stop bit, no parity
    U0DLL = 0x87; // Set baud rate to 9600 bps
    U0DLM = 0x01;
    U0LCR = 0x03; // Enable UART0
    U0IER = IER_RBR |  IER_THRE; // Enable THRE and RBR interrupt

    U0FCR = 0x07;

    VICVectAddr0 = (unsigned long)RS232_ISR;
    VICVectCntl0 = 0x00000026;
    VICIntEnable = 0x00000040;
}

void __attribute__ ((interrupt("IRQ"))) RS232_ISR(void) {
    int iir_value;

    iir_value = U0IIR; // read the interrupt identification register

    // Check if the interrupt was caused by a received character
    if (iir_value & IIR_RDA) {
        char rx = U0RBR; // read the received character
        U0THR = rx;

    // Check if the interrupt was caused by the transmitter becoming empty
    } else if (iir_value & IIR_THRE) {
        U0LSR; // read the line status register to clear the interrupt flag
    }

    VICVectAddr = 0x00; // Acknowledge the interrupt
}

In the main function, led blinks every 1sec and if any uart0, recv interrupt occurs, interrupt handler should be reached, but it is never reached I transmit a char from my PC, the code should read it and transmit it back to the Pc, but it is not doing that. Appreciate any help

Answer 1

I found out that we need to update the Startup.S in this way.