Lpc2000

At 12:03 PM 11/19/04 -0600, you wrote:
>   Won't the watchdog reset cause P0.14 to revert to an input?

Good point Bill, I had forgotten that and that the WD state was 
checked.  That makes the hole much smaller.  I still don't like the idea 
that a jump to 0 can invoke the ISP (it does eliminate the possibility of 
using that as a soft reset to restart the system) but barring executing a 
null pointer the rest of the avenues are covered.  So using P0.14 as an 
output should be relatively safe.  Like wise as an input if you can 
guarantee the reset state.  It would be safer still though if the boot 
actually cared about the state of the reset pin.

As far as having pins mean different things on startup, I'm used to 
that.  The ST10 had (I think) 16 pins to configure the processor that were 
read on input on a reset.  They were ignored if the processor restarted for 
ANY other reason.  The Intel 196 had similar (but fewer) pins that could 
place the chip into test modes if not in the right state on reset.

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