Here is the initialization procedure I've followed as shown the manual for the PIC18F45K22:
Timer3 is initialized to run wide open on the 4 MHz system clock/4 = 1 uSec per count.
TMR3H = 0; // Clear high byte
TMR3L = 0; // Clear low byte
clrbit(PIR2, TMR3IF); // Clr TMR3 int flag
setbit(PIE2, TMR3IE); // Set timer 3 interrupt enable
setbit(T3CON, TMR3ON); // Set timer 3 running
setbit(INTCON, PEIE); // Set peripheral device interrupt enable
setbit(INTCON, GIE); // Set Global Interrupt Enable
di();
TMR3H = 0xFF; // SET high timer for 125 usec
TMR3L = 0x83; // FF83 == 125 uSec to rollover
ei();
The timer is running but there is no interrupt produced on the tick over from FFFF to 0000.
Can anyone suggest what the heck I'm doing wrong?