aduc7026 ADC中断程序没有相应输出

下载官网上adc中断程序到开发板，但dac并没有相应的输出。

程序如下：
/*********************************************************************

Author       : ADI - Apps          www.analog.com/MicroConverter

Date       : Sept. 2005

File       : Multint.c

Hardware    : Applicable to ADuC702x rev H or I silicon
               Currently targetting ADuC7026.

Description : Example program using two IRQs and 1 FIQ.
  Timer1 causes an IRQ which compliments P4.2.
  XIRQ0 causes an IRQ which compliments P4.2.
  ADC causes an FIQ which outputs the value on ADC0
  to DAC1.

*********************************************************************/

#include // Include ADuC7026 Header File

// Function Prototypes

void My_IRQ_Function(void); // IRQ Function Prototype
void My_FIQ_Function(void); // FIQ Function Prototype
void ADCpoweron(int);
void delay(int);

void DemoConfig(void);
long ADCconvert(void);
void My_IRQ_Function(void);

int main (void)  {

  DemoConfig(); // set up ADC, DAC, & reference

  IRQ = My_IRQ_Function; // Specify Interrupt Service Rountine
  FIQ = My_FIQ_Function; // Specify Interrupt Service Rountine

  GP0CON = 0x00100000; // Enable ADCbusy on Pin 0.5
  GP4DAT = 0x04000000; // Configure P4.2 as output
  GP3DAT = 0xff000000; // Configure port 3 as output
  // Timer 1 configuration
  T1LD = 0x20000; // Counter Value
  T1CON = 0xC4; // Enabled,Periodic,Binary and CLK/16

  IRQEN = XIRQ0_BIT+GP_TIMER_BIT; // Enable XIRQ0 and Timer1 IRQ
  FIQEN = ADC_BIT; // Enable ADC FIQ

  while(1) {
  GP3DAT ^= 0x00ff0000; // Compliment P3
  ADCCON = 0x6E3; // single conversion
  delay(0x2000); // Delay Blinking of P3
  }

  return 0 ;
}

void delay (int length) {
while (length >=0)
length--;
}

void DemoConfig(void) { // ADC, DAC and Reference configuration
  ADCpoweron(20000); // power on ADC
  ADCCP = 0x00; // conversion on ADC0
  DAC1CON = 0x13; // AGND-AVDD range
  REFCON = 0x01; // internal 2.5V reference
  return;
}

void ADCpoweron(int time) {
  ADCCON = 0x20; // power-on the ADC
  while (time >=0) // wait for ADC to be fully powered on
time--;
}

/********************************************************************/
/*                                                                */
/* Interrupt Service Rountine */
/*                                                                */
/********************************************************************/

void My_IRQ_Function() { // example with two IRQ

  if ((IRQSTA & GP_TIMER_BIT) != 0) { // Timer1 IRQ?
  T1CLRI = 0; // Clear Timer IRQ
  GP4DAT ^= 0x00040000; // Complement P4.2
  }
  if ((IRQSTA & XIRQ0_BIT) != 0) { // external IRQ?
  GP4DAT ^= 0x00040000; // Complement P4.2
  while(GP0DAT & 0x00010){} // wait for XIRQ to be low again
  }
  return ;
}

void My_FIQ_Function() { // example with one FIQ
  if ((FIQSTA & ADC_BIT) != 0) // ADC FIQ ?
  DAC1DAT = ADCDAT; // Output ADC0 Value onto DAC1
  return ;
}