HV Parallel Programming Project

[microburst]

Has anyone successfully built and used one of the Uno-based HV Parallel Programmer projects? ("HV Rescue", "HV Rescue Shield by Mighty Ohm")

I've built (from scratch) two different designs and neither work. As a matter of fact, I destroyed the device signature on one of my 328p chips trying to get it working. Trying to describe the issue isn't easy . . . the sketches behave erratic.
The fuse values I plug in (serial monitor) don't get burned, read/verify functions return random values, etc. etc.

I've constructed much more complex projects/circuits in the past, I have 40+ years as a senior electronics tech and this time I'm stumped.

Any thoughts, suggestions?

[TomGeorge]

Hi,
Can you please post links to the project you are describing?

Thanks.. Tom..

[gilshultz]

Posting an annotated schematic as how you have it setup would help.

[microburst]

Thanks for the reply. Here they are:

HV Rescue Shield 2

HV Rescue Simple

Second example using a Pro Mini. Both designs use same pin connections and signals (as per Atmel datasheets), but use slightly different method of applying 12V RESET.

[microburst]

Schematic for the first one:

Having trouble uploading schema for second one . . . standby

[microburst]

Second one:

[microburst]

I'm using a typical breadboard with jumper wires. 12VDC is supplied by a separate 7812 based supply.

Course of matter that I checked, rechecked, rechecked, and rechecked again wiring and procedures.

RF bypass caps on power rails doesn't help.

Hoping for someone that says "Hey! I built that and it worked for me!"

[westfw]

i made a self-designed (direct from the datasheet) HV parallel programmer for ATtiny28 chips, and it worked. I used an atmega4809 as the programmer, though - an uno-class chip starts to get tight on the pin count by the time you need ~16 connections to the target, plus control for 12V, plus com with your computer...

That's probably not much help.