I programmed the LPC935 device like this:

The Real Time Clock generates an interrupt every 1 second.
It's interrupt priority is 2.

During the same time the A/D Converter unit should generate interrupts every 1us.
It's interrupt priority is 1.

The Interrupt routine of the A/D Converter is only gonna serviced, if the Real Time clock has a lower priority then the ADC.(But then the Real Time Clock wouldn't be serviced any more)

If I have only one of the two applications in my Programm everything works fine.

But I would like to have the ADC interrupt be serviced during the Real Time clock Interrupt is not active.

Someone any idea?

{pre}
#include <Reg935.h>
#include "LPC935.h"

void main(void)
{
unsigned char duty_cycle_AD;
unsigned char pwm_rate;

PORT_init(); // sets up the Ports
CCU_init(); // sets up the CCU
ADC_init(); // sets up the ADC
RTC_init(); // sets up the RTC

while(1);
}

void PORT_init(void)
{
P1M1 = 0x00; // Push Pull output for all P1 Ports
P1M2 = 0xFF;
P1=0;

P2M1 = 0x00;// Push Pull output for all P2 Ports
P2M2 = 0xFF;
P2=0;

EA = 1; // Enable Interrupts
}
{/pre}