Unrecognized signature for atm328p-pu is End of story?

Hi, The Atmega boardprogrammer sketch gives out Unrecognized signature for an atm328p-pu. What does this mean? Buy another one?


Not really... don't trash it just yet.

There is a special king of programming, called "high-voltage parallel programming" (HVPP) that can rescue Atmegas in such state.

I have a 328-PU (of the non-P type) that is giving me the same trouble. I built a Fusebit Doctor, which apparently has the magical powers and wisdom to fix such annoyances.

I can't tell you yet if the fusebit doctor works because although I have built the PCB, my Atmega8 9the uC used by Fusebit doctor) hasn't arrived yet.

I understand that I have to bild a pcb to fix this problem?

bobbele: I understand that I have to bild a pcb to fix this problem?

Or buy a ready made one, like this one: http://mightyohm.com/blog/products/hv-rescue-shield-2-x/

It does the same thing, and if youll be working with lots of Atmegas, having one of these handy is always a good idea... you never know when "something" might hit the fan.

I remember you posted earlier about the Serial not working.

Were you able to get the board detection sketch working correctly? If the board detection code works, you should be able to program the chip.

Answer to AlxDroidDev:

No not a lot of atmegas, this is my first hardware/programming experience. That is not usefull for me. And to much to bild myself. Tanks for your reaction.


Hi Ikazone,

Yes that was all right so far with the detector. So OK, Sounds good...should be able to, but When I run the board programmer it stops there. Normally you have to make a choise for frequention there. But in my case that question dosn`t appear. Any idea what to do now? run another boarddetector?



Its hard to say whats happening without looking at you’re setup.

Just to make sure you’re loading up this sketch?

The detector and programmer are 2 different sketch. The detector does stop after it prints out bunch of stuff.

Or are you using this with ArduinoISP?

In ether case make sure you have things bread boarded correctly.

Unrecognized signature

What signature is reported (turn on verbose mode)? An unrecognized signature usually means either a wiring problem (reports signature of 000000) or that you don't have the chip that you thought you had (atmega328 vs atmega328p) A chip with bad clock settings is also possible (set for external oscillator or crystal when none is present) (but usually you'll get a complaint before you get to the signature phase.) That's possible to fix by providing an external clock. I'm not sure what happens if you've got a chip with disabled ISP or RESET pin. Those are the errors that you'd need HV parallel programming to fix. I suppose it's also possible that you have a completely fried or fake chip...


Yes I am doing a Tutorial ArduinoTo Breadboard same constellation and
your advise was good… I shuffled with the connections and signature was recognized,
but furtheron after programming the bootloader it seems to have flashed nothing.
I tried again both detector and programmer signature was not recognized.
I tried again and again it went good and went bad but ALWAYS in the end: all verification errors,
as if it din`t flash at all.
Maybe bad voltage then?
But at first (going to sleep) I am going to make soldered contacts anyhow.
I will come back later with the results.

Thank You for your advise


hi westfw,

Please look at my earler post today for an answer to your questions. (I am very tiered now, sorry)

you wrote: I suppose it’s also possible that you have a completely fried or fake chip…

Yes I think so too, but probably just not completely: so i`ll be buisy tomorrow with a little hope.