uart interrupt not working

Hi everyone,

I'm using the Altera DE2 board. I am trying to setup a serial link between PC and UART, but UART doesn't seem to be receiving anything. Here's the code that I have. Could anyone tell me what's wrong with it? Thanks. I'm using hyper terminal to send the data and I have jtag_uart mapped as stdin/stdout/stderr to display the char I received through the UART.

# include <stdio.h># include "system.h"# include "sys/alt_irq.h"# include "altera_avalon_uart_regs.h"

# define RRDY_MSK 0x0080

/* Declare a global variable to hold the uart data value */

unsigned char uart_data;

//ISR for receiving

static void IsrRxUart0(void* context, alt_u32 id)

{

/* cast the context pointer to an character pointer.*/

unsigned char* uart_data_ptr = (unsigned char*) context;

//if RRDY bit of status register is clear

if((IORD_ALTERA_AVALON_UART_STATUS(UART_0_BASE) & RRDY_MSK) == 0x0000)

{

//IOWR_ALTERA_AVALON_UART_STATUS(UART_0_BASE, 0x0000);

*uart_data_ptr = IORD_ALTERA_AVALON_UART_RXDATA(UART_0_BASE);

}

// enable UART interrupt for read ready (setting IRRDY bit)

IOWR_ALTERA_AVALON_UART_CONTROL(UART_0_BASE, 0x0080);

}

/* Initialize the uart */

static void InitUart0()

{

/* Recast the uart_data pointer to match the

* alt_irq_register() function prototype.

*/

void* uart_data_ptr = (void*) &uart_data;

//enable UART interrupt for read ready (setting IRRDY bit)

IOWR_ALTERA_AVALON_UART_CONTROL(UART_0_BASE, 0x0080);

//register UART receiver ISR

alt_irq_register(UART_0_IRQ, uart_data_ptr, IsrRxUart0);

}

int main()

{

InitUart0();

while(1)

{

if(uart_data)

{

printf("This is the character received: %c \n", uart_data);

}

}

return 0;

}