Lpc2000

Hi.
There's no such thing as a dumb question. There are lazy questions
(where the answer is obvious when you read the user manual).
There are dumb answers.

Why might you use the prescaler?
It is only a 32-bit counter. So at 60 MHz, it will overflow at
2^32/60000000 = 71 seconds (I think). What happens if you want
a time longer than that?

The faster things run, the more power they use. So for the most
power-efficient applications, you might choose to slow things
down as much as possible. For this particular case it is a weak
argument, but other peripherals are more power-hungry and
so you can save some power this way.

Philips also say that you can divide PCLK to a slower rate than
core in case some of their peripherals cannot run as fast as the
arm core. The also say that all current peripherals can run at
60 MHz so there is little cause to do this right now. But in future?

Maybe you have a system that runs in two modes, with the
processor fast or slow depending (say) whether you're running off
mains or battery. If you can re-program the peripherals so they
always run at the same pace (even though the arm core is different)
then you don't need to recalculate all the timings etc.

There's no killer reason. But one of my timers happens to have the
prescaler divide by 60 so I have a 1MHz tick. It makes my
calculations easier.

Hope this helps,
Danish

--- In lpc2000@yahoogroups.com, "sherifkamelzaki" <sherifkamelzaki@...> wrote:
>
> hi i have a very dump question y do we use prescale while we can enter 
> any value  we want in the TOMR0
>