Lpc2000

Hi,

just discovered something in the Users Manual of the LPC2138. Several
months ago there was a questions how to count external events with a
LPC2106, to my surprise the answer was, generate an interrupt und do a
software counter :-(

In the LPC2130 series however, it is possible to select any of the
CAPIN pins to be an external counter, counting falling, rising or both
edges. The Match registers can still be used to generate an interrupt.
The rather short description, pretty much limited to a new register
can be found in the UM (posted here in the files section) on page 179,
table 130.  :-)

There was no indication in the pinout that the CAPIN pins can be used
as counters so I thought this was worth pointing out here.

Cheers, Bob

Just to note.

I have an impression, that 90% of this forum problems are caused by
bad documentation of the LPC2000  (though the parts are nice).
It seems, that Philips people, monitoring the forum do not pay 
attention to this fact. Or, maybe, it is done knowingly?
The LPC2129 UM is not edited from May 2004, though only here were 
reported a lot of uncertainties.
Here is one more:
if you try to read I2CONSET register, all bits are zeroed.
I spent a couple of hours, before understanding, that

I2CONSET |= STA; (not wrong for most of other registers)

resets the I2EN bit and should be replaced by:

I2CONSET = STA;

So working with LPC2000 we have inventing a new science "an 
experimental programming", though the traditional programming is 
theoretical for sure.

Varuzhan


--- In lpc2000@yahoogroups.com, "lpc2100_fan" <lpc2100_fan@y...> 
wrote:
> 
> Hi,
> 
> just discovered something in the Users Manual of the LPC2138. 
Several
> months ago there was a questions how to count external events with a
> LPC2106, to my surprise the answer was, generate an interrupt und 
do a
> software counter :-(
> 
> In the LPC2130 series however, it is possible to select any of the
> CAPIN pins to be an external counter, counting falling, rising or 
both
> edges. The Match registers can still be used to generate an 
interrupt.
> The rather short description, pretty much limited to a new register
> can be found in the UM (posted here in the files section) on page 
179,
> table 130.  :-)
> 
> There was no indication in the pinout that the CAPIN pins can be 
used

> as counters so I thought this was worth pointing out here.
> 
> Cheers, Bob