Lpc2000

At 07:38 AM 3/2/04 +1100, you wrote:
>Hi ,
>
> > industrial controller board.  2 questions.  I assume the device can
> > be used to count external pulses, encoder signal, which pin(s) can be
> > used for a counter i/p?
>
>The Timers have capture/compare channels, but I haven't looked yet at
>counting pulses with it.

You can't, at least on the variants that I've looked at.  This is one of 
the odder lacks on the chips from my perspective [others have their own 
choices ;) ].  I'd have gladly traded off the RTC for more timer 
resources.  The little RTC functionality I have any use for can be easily 
done with timers and since there is no timer supply separate from the CPU 
supply....

I must admit I really don't see the point of the RTC on the LPC it's only 
purpose seems to be to save a little arithmetic.

>With "encoder signal", do you mean you need to input a quadrature signal
>(eg. from a shaft encoder) to the LPC2000 ?
>That's one thing missing from the LPC2000. I haven't seen too many MCUs
>that had that capability built into its timers.

I've seen a few, it's more common on DSPs though.  Quadrature is fairly 
easily converted to pulse + direction though and more micros support that 
(eg ST10/C166, 196, some Motorola parts if I remember correctly).

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III