16MHZ = 250nS per instruction cycle , if Prescaler value = X , then 250nS*X = time of TMR0+1 , 1S/(250nS*X) = Y , Y = TIMER count value , So , TMR0 not long enough to count , Maybe use Timer1, or use the other byte to count TIMER0 interrupt ,
2 . sure , you can use them at the same time , Why not ! in PIC18F , you can set high priority and Low priority for each interrupt source ,
I use 18f458@16MHz,I want the tmr0 to interrupt 1 times per second,how to set register tmr0 and the prescale value?May i enable timer0 and timer1 interrupt at the same time?