I am trying to program a PIC16F77 using a PICKit2 programmer. This
isfor a project that was completed a long time ago and I'm now trying
toupdate it. The programmer correctly IDs the device and I can load
thehex file and program it. When I verify it, I get a verification
successful message. However, when I plug the device into my
workingcircuit (verified with a previously working MCU), it won't do
anything. All of the I/O pins read 0V even if I try to drive them
high. I've tried programming 4 other 16F77s and a 16F84A all with the
same result- successful programming and verification, yet they don't
work in a circuit. I've tried programming with a PICKit2 clone from
Sure Electronics and with the one from Microchip, but get the same
results with each. If the MCUs are bad, I wouldn't expect the verify
to pass. I've read about the possible need of adding an external
power supply in the event the USB cable can't supply the proper
programming voltage. Could that be the problem, and how would I go
about doing that? I have the programmer hooked up to a board with a
DIP ZIF socket. Any ideas?

Thanks

What about the fuses that set the Oscillator mode, etc.? Are you
programming them correctly? They are seperate from the hex file....




"mcki0127" <mcki0127@hotmail.com> wrote in message
news:1192731685.677796.13090@e34g2000pro.googlegro ups.com...

On Oct 18, 5:42 pm, "Bill Chernoff" <b...@star-techno.com> wrote:
I've tried using a 4MHz and a 20MHz crystal oscillator (20MHz in the
existing circuit) and 20pF capacitors. I've also tried setting the
configuration bit to XT and HS, but still get the same results.

I have the same problem. However, when I make my program smaller than 180
bytes it works. Go figure...