I haven't done much PIC work since leaving $JOB over 2 years ago. =20
Recently, I've been getting back into it.   The subject line describes=20
today's experience.
I had bought an Olimex PIC-P28 dev board as a platform for some quick=20
projects.  One such project came up where I wanted to generate a PWM=20
signal with a PIC to test some motor speed control FETS[1].  I made up a=20
program that output a PWM signal, and it reflected the PWM signal on the=20
LED, and a button cycled the duty cycle in 10% steps from 0 to 100%.  I=20
used HiTech C Lite with MPLAB X and an ICD3, and observed the output=20
with my old Tektronix 453 bought around 1988, I'd guess.
It was working nicely, so today, I soldered a header on the Olimex board=20
to extend the PWM output to a radio shack breadboard (we used to call=20
them continental specialties boards).  I connected it up, powered it on,=20
and nothing.  Unplugged breadboard, still nothing.  Connected it to ICD,=20
and try to debug, and MPLab tells me the device ID is 0.   I ran=20
Debugger Self Test and it passed.
Long story short, the pins I had selected on the Olimex board are on a=20
semi documented "grtound bus", so I had shorted the board's VCC to=20
GND.    Looking at the Olimex manual, the pictures show a hint of=20
shading that should have told me this.  The manual mentions GND bus, but=20
does not specify where it is.   It also mentions Vcc bus, so I better=20
locate that.

So:
o Crappy Doc.   Olimex could do a better job
o Crappy software - MPLAB X should have known the target board had=20
shorted supply.
o Crappy assumptions - I assumed my wiring was OK.

Fortunately, the board survived and moving the header allowed me to test=20
FETs.

Joe W


[1] Another story about crappy product from an Asian supplier on Ebay. =20
A new speed controller had a bad 555 timer and possibly bad FETs.
--=20
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