Been diviing into the description of the use of the interrupts for the 18F252 device and want to test out my understanding relative to the relationship between the prescaler and 8/16 bit registers of the timer.

If I'm using a 4Mhz oscillator and an internal clock for the Timer then my effective frequency going to the 8 or 16 bit counter is either:

1 Mhz for a Prescale value of 1
500 Khz for a prscale value of 2
etc....

Then this frequency is fed into the counter and when it overflows an interrupt is generated.

Correct?

So if I want an interrupt every 0.5 seconds I could use a prescale of 8 giving me a frequency of 125khz (8us period) and preload the 16bit register with 3036 (decimal)

I reached this figure by dividing 0.5 sec by 8 us and getting 62500 pulses required to overflow the 16bit counter. With no preload, the counter would take 65,536 counts to overflow so I would preload it with 65536-62500

Correct?

The other thing I'm not sure about is the ability to configure the timer for 16 bit reads and writes. I still need to read TMR1L and TMR1H separately... don't I?

I'm sure I'll have more questions when I attempt to program this later on this weekend.

thanks...Chris