Lpc2000

--- In lpc2000@yahoogroups.com, "moostieuk" <moostieuk@y...> wrote:
> I've tried this before, it appears that once you've put the pins
> capture/compare mode you cannot read the state directly from the
> pin.  
> 
> I was reading a PWM signal, so in the end I just ended up creating
> a state machine and in the capture interrupt change the edge
> triggering for the next capture.

A state machine won't work for my application.  I suppose I can
use the capture pins to trigger the interrupt, and read the state
from another set of pins that mirror the values.  But what a waste
of pins!  I suppose I could move to a 2114 to get some extra pins,
but then I need to squeeze the RAM requirements down to only 16k.
I hate tradeoffs.

The Philips User Manual is clearly wrong about this.  I read the
docs carefully, believed what they said, and now I have to toss a
couple of prototype boards in the trash and rewrite the software
when I am already behind schedule.  They should fix their dang
docs and not leave this for the next engineer to trip over.  This
isn't a printed manual, it is just a PDF file, so it shouldn't be
much effort to fix. 

    -bob


> --- In lpc2000@yahoogroups.com, "bobbruce000" <bobbruce000@y...> wrote:
> > I have several pins configured as capture pins which interrupt on
> > either a rising of falling edge.  Then in the interrupt handler
> > I read the IOPIN register to get the value.
> > 
> > According the description of the IOPIN register on page 81 of the
> > Philips 210x User Manual, this should work.  I quote:
> > 
> >   "The current state of the port pins can always be read from
> >     this register, regardless of pin direction and mode."
> > 
> > But it doesn't seem to work.  I have double and triple checked
> > my code, and I 95% sure this is not a software bug.  The capture
> > pins always read zero.
> > 
> > Is the user manual wrong?
> > 
> >     -bob