Voting resources, early voting, and poll worker information - VOTE. ... Adafruit is open and shipping.
0

A Tiny Tiny Brick
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

A Tiny Tiny Brick

by stinkbutt on Tue Oct 26, 2010 1:34 pm

I think I just bricked my ATTiny13. Which isn't that big of a deal, I suppose, since it's a frigging ATTiny13. They cost less $2 a pop so I suppose I could just throw it out and use the next one. However, perhaps it's salvagable. So here's the problem:

I altered the fuse bits. OF COURSE I altered the fuse bits, right? If someone bricks their AVR it's almost invariably that. I changed the lower fuse from 0x6A to 0x6B, which corresponds to changing the internal clock from 9.6 MHz to 128 KHz, and NOT changing anything else, including keeping divide-by-8 flag (CKDIV8), so now I believe that my ATTiny13 is running at 16 KHz. Now I can't program the thing any more. Every time I try anything (reprogramming the fuse, putting the hex, etc...) I get no joy:

Code: Select all | TOGGLE FULL SIZE
Programmer Type : USBtiny
Description : USBtiny simple USB programmer, http://www.ladyada.net/make/usbtinyisp/
avrdude: programmer operation not supported

avrdude: Using SCK period of 10 usec
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.


Now, I've also tried the -B and -i flags to slow down the programmer (AVRFreaks have suggested that) but it appears that -B caps at 250 us which ought to be sufficient, since 250 us corresponds to 4 KHz, exactly 1/4 of the speed of my ATTiny13, but I get the same error, only instead of 10 usec it reads 250 usec:

Code: Select all | TOGGLE FULL SIZE
Programmer Type : USBtiny
Description : USBtiny simple USB programmer, http://www.ladyada.net/make/usbtinyisp/
avrdude: programmer operation not supported

avrdude: Using SCK period of 250 usec
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.


Now, I've absolutely confirmed that the wiring is correct. I've programmed two other Tiny's without incident, primarily because I wasn't foolish enough to touch the fuses on them. I've also confirmed that I did not disable the reset pin.

So my question is: Is there any way to talk to a 16 KHz ATTiny using the USBTinyISP? I don't want to waste the chip - mostly out of principle at this point - and I'd like to eventually make 16 KHz actually work as a clock speed. I'm beginning to suspect that my choices are going out and buying a Dragon or a Fuse Doctor.
Red M&M, Blue M&M: They all wind up the same color

stinkbutt
 
Posts: 593
Joined: Wed Feb 17, 2010 2:40 am

Re: A Tiny Tiny Brick

by stinkbutt on Wed Oct 27, 2010 12:32 pm

Looks like the chip's borked, then. Ah well.
Red M&M, Blue M&M: They all wind up the same color

stinkbutt
 
Posts: 593
Joined: Wed Feb 17, 2010 2:40 am

Re: A Tiny Tiny Brick

by jgotthardt on Thu Oct 28, 2010 1:20 pm

There is a minimum ISP frequency below which the AVR chip can no longer be programmed. But you can erase the chip at a very low speed using the procedure in this link:

http://www.evilmadscientist.com/article.php?story=avrclockbits
John

jgotthardt
 
Posts: 33
Joined: Mon Dec 03, 2007 11:58 am
Location: Massachusetts

Re: A Tiny Tiny Brick

by stinkbutt on Thu Oct 28, 2010 2:27 pm

Holy crap, this is EXACTLY what I did. This is perfect! (Well, I think it's perfect. We'll see if I can unbrick it tonight.)
Red M&M, Blue M&M: They all wind up the same color

stinkbutt
 
Posts: 593
Joined: Wed Feb 17, 2010 2:40 am

Re: A Tiny Tiny Brick

by stinkbutt on Fri Oct 29, 2010 1:34 pm

...but it didn't work. Screw it I just threw the thing out. There's a limit to how much effort I'll spend trying to save a $1 part.
Red M&M, Blue M&M: They all wind up the same color

stinkbutt
 
Posts: 593
Joined: Wed Feb 17, 2010 2:40 am

Re: A Tiny Tiny Brick

by mightyohm on Tue Nov 02, 2010 3:09 pm

I'm working on adding ATtiny support to the AVR HV Rescue Shield. With any luck it will be included in the next major release, hopefully later this month.

Stay tuned...
http://mightyohm.com/blog/products/avr- ... ue-shield/
mightyohm
 
Posts: 19
Joined: Mon Sep 22, 2008 8:30 pm

Re: A Tiny Tiny Brick

by wholder on Thu Nov 18, 2010 3:36 am

If you own an Arduino, here's a simple way to "unbrick" ATTiny chips that works for me:

https://sites.google.com/site/wayneholder/attiny-fuse-reset

Wayne

wholder
 
Posts: 59
Joined: Mon Mar 16, 2009 2:09 pm

Please be positive and constructive with your questions and comments.