I am working on a project that uses 3 interrupts on an Atmel 89LV51:

Serial
INT0
Timer0

The Serial interrupt occurs when data is comming in from the serial port, and I use the interrupt to store the incomming data into a small FIFO buffer.

INT0 occurrs independant of the Serial Port and during INT0, I setup Timer0 to interrupt the INT0 interrupt. This code also works as long as I do not enable the Serial Interrupt.

I can get INT0 and Timer0 to work just fine together, but if I enable the SErial interrupt, somewhere it crashes.

I've tried disabling outside interrupts from inside the interupt service routines, and I've also tried playing with the priority of the interrupts without luck.

The only option I have gotten to work is

if (some condition is true)
{
IE = 0x90; // turn on serial interrupts
while(1); // do nothing else
}

if (some other condition is true)
{
IE = 0x83; // enable INT0 and timer0
while(1); // do nothing else
}


I've tried to use

IE = 0x93; // enable all the interrupts I want
while (1); // let the interrupts work


but this does not work.

Any ideas?

adam