Very Simple ICSP Programmer

[marksk]

tried my laptop over the weekend to no avail. i used an external supply for the +5v, but each time i tried i got an "verification failed at 0000h". i also tried applying +12v to MCLR to get it into programming mode, but that didn't work. i prefer to use the laptop for several reasons:

1. it fits nicely in my work area
2. it's 10 years old and isn't used, so if it blows it's no big loss
3. i've got problems if i use my desktop pc and it blows

i have an old 486 pc in my garage, but i don't have a spare monitor or keyboard for it.

can someone point me to a schematic that would allow me to use the laptop? (preferably with easy to find parts) if i use my desktop for the LVP programming, what are my changes of killing the pc?

thanks!

[nomad]

you can't just apply +5, and +12 for power and Vpp and have it work. there's timing issues, when it applies the voltage, which is first applied, to even get into programming mode. these voltages need to be controlled by the programmer. some newer JDM's use external supplies, but it still controls when they're applied to the pic.

as everyone has been saying, break down and buy the pickit2, or other.

by the time you build the cheapo serial one, buy a cable, waste hours upon hours trying to get it to work, you'll have spent way more than if you bought
the pickit (or other) in the first place..

here's the kicker, even after you get an enhanced jdm, get it to work, get/make external supplies for +5/+13, make a housing for it with switches etc, and tweak the software to run off your laptop with a usb converter...............

You'll end up buying a different programmer for the other features.!
(say um, pickit2? for serial i/o, logic injection/analyzer, etc..)

oh, and if code protect is on, it will always fail verification.. even if it programmed fine, it will be unable to read the code to do the verification. :/