20X2 HPWM problem


Hi ya

I'm using a 20X2 which processes various RC input signals, reads a couple of pots and three jumper links, has several digital outputs and also gebnerates a single PWM stream.

Having designed and built a strip-board layout I wrote some trivial test programs to exercise the hardware before starting on the programming proper. The bits all worked in isolation.

All was going well until I found one of my (previously tested) jumper link inputs had frozen into the low condition (it's normally pulled up by a 47K resistor, and the jumper, if fitted, links it to 0v). After some effort I have determined that invoking the HPWM command is responsible for pulling it low.

To eliminate my software application I wrote the following program

high B.7 'turns the LED on - just so I know its working
pause 3000 'time to see input C.0 (leg 10) is sitting high

hpwm 0,0,%0100,100,50 'I'm using HPWM C (leg 7)

do 'prevent HPWM terminating

sure enough after 3 seconds leg 10 takes a dive to 0v. The PWM on leg 7 runs just fine. I've even bent the entire HPWM set of legs out of the socket and C.0 is still pulled low.

Any ideas????



I've altered my layout so that I can use the regular PWM on C.5 instead - and everything works fine now, so I'm not stuck, but I'm still curious !