I am not familiar with Avrdude's behavior or the ATTINY13A's behavior to know if I am getting false hope here. With the vast experience base here, I appreciate some input.
This is the scenario: By mistake, I connected the ATTINY13A to 12V. So I think it is toasted. I have some replacements from Mouser enroute. So, I don't so much need the chip, but I hate to loose the week's "playtime" while I wait for the replacement.
Recalling that some has use 12V for fixing fuse issues when fuse is set wrong (disabling SPIEN), I thought perhaps 12V wouldn't kill the chip. So I decided to give AvrDude a go and try to read the chip. AvrDude seem to be reading something except it is always reading zeros including chip ID. The fuse reads zero, so SPIEN is disabled assuming that is right - which could not be right because if it is right, it means SPIEN is disabled and AvrDude could not have communicated with it...
AvrDude is behaving as if it is communicating, and it seems to think the chip is communicating back. Perhaps the chip is not stone dead... I thought... So I do a little more looking into.
Other searches said a 000000 for chip ID is lack of an external clock. So, I gave it a 1Mhz square wave at pin2, clk-in pin. That doesn't help.
I hook up the "high volt fuse recuse" circuit found here:
http://www.instructables.com/id/Simple-and-cheap-Fuse-Doctor-for-Attiny/And the circuit is:
I don't have a BC547 or an 2N3904. I have a pn2222a and a pn3565. It does seem to switch the 12V, I got 11V-ish at the collector. I am not sure the either is fast enough for the circuit. ATTINY13 does not communcate (
if(Serial.available()>0) is false readfuse() doesn't come back) so the TINY13A could in fact be dead. But AvrDude acts as if it is talking to it and it is talking back (with zeros). AvrDude thinks it can read and write flash/fuse/eeprom (but it wont verify of course since it always read 0.)
Question:
(1) Does AvrDude do any communication check? Or is it pretending the Tiny13A is talking back even when it is stone dead.
(2) Given the way the Tiny13A stopped working after connecting it to 12V, is what I described the behavior of a dead chip or a recoverable chip?
(3) For the "recuse circuit", is pn2222a or a pn3565 adequate for the job?
Mouser should be sending me the Tiny85V, but I sure like to know if the Tiny13A is recoverable so I can continue development while the 85V makes its way to me.
Thanks for sharing your experience and knowledge!
Rick