[avr-chat] avrdude: ATtiny45 unresponsive after writing to flash

[Daniele Nicolucci (Jollino)]

Hello all,
I just recently started playing with microcontrollers so I'm quite  
ignorant about them, but I'm learning. :)

I have a couple of ATtiny45s, a couple of ATtiny2313s and several  
ATmega8s and ATmega8Ls. So far I'm focusing on the tinies to learn the  
basics and whatnot. My set-up consists of an AVRISP from DigiKits.com  
(essentially a CP2101 USB-to-UART adapter, with an ISP connector built- 
in and connected to the right pins; it is seen as an STK500v2) and avr- 
gcc + avrdude on OS X.

With the ATtiny2313, everything went fine and I actually built a  
little thing it. With the ATtiny45, though, I have some serious  
problems I can't figure out.
When I flash a small program, say under 150 bytes or so, everything  
goes smoothly: it erases, flashes and verifies perfectly. For  
instance, this hex works:
---8<---
:100000000EC028C027C026C025C024C023C022C0DF
:1000100021C020C01FC01EC01DC01CC01BC0112499
:100020001FBECFE5D1E0DEBFCDBF10E0A0E6B0E05F
:10003000E4E6F0E003C0C89531960D92A036B10712
:10004000D1F710E0A0E6B0E001C01D92A036B107E4
:10005000E1F701C0D5CFCFE5D1E0DEBFCDBF8FEF57
:0400600087BBFFCF8C
:00000001FF
--->8---

When I try to flash something bigger, the programmer enters a coma  
state right after sending the bytes to be flashed, to the point that  
avrdude reports timeouts from the programmer. At that point I can't  
even kill it, and ps (the process viewer!) reports it as "E", which  
means "trying to exit but not really succeeding".
This is a hex file that does that:
---8<---
:100000000EC028C027C026C025C024C023C022C0DF
:1000100021C020C01FC01EC01DC01CC01BC0112499
:100020001FBECFE5D1E0DEBFCDBF10E0A0E6B0E05F
:10003000E0EBF0E003C0C89531960D92A036B10711
:10004000D1F710E0A0E6B0E001C01D92A036B107E4
:10005000E1F723C0D5CFC198882311F4C09801C01F
:10006000C09AC19A08951F93CF93DF93182FC0E0D1
:10007000D0E0812F99270C2E02C0880F991F0A9477
:10008000E2F7E9DF2196C830D10599F7DF91CF91EA
:100090001F910895C298C29A0895CFE5D1E0DEBFBE
:1000A000CDBF8FEF87BB84E6DEDFC298C29AFFCF59
:00000001FF
--->8---
The flash write seems to work (I'm not entirely sure as I was building  
that program a piece at a time, checking that everything worked as  
expected), but the flash read for the verification process doesn't  
even start. Inhibiting the verification stage times out anyway, as it  
can't read the fuses.
I put a log (with -vvvv) of what happens at http://jollino.it/stk500ko.txt 
, maybe someone can make some sense out of it.

I am running avrdude 5.3.1 installed through macports, but I also  
compiled 5.5 on my own and the problem doesn't change.

From the little understanding I have (so far) of microcontrollers, it  
can't be related to bugs in the source code of the hex file, as  
avrdude merely send streams of data to the chip to have it flashed  
into its memory. Then why does this happen?
I also noticed a weird thing: with the ATtiny2313, the programmer  
worked fine even without powering the circuit (isn't that weird?).  
With the ATtiny45, it has to be powered up otherwise it will not work  
at all.
I have been researching on the net, but I haven't found anything that  
could apply to my problem. Of course, it might also be a matter of not  
searching properly... in which case I apologize.

Any hints would be greatly appreciated. :)

Thank you very much in advance.


Daniele
--
Daniele Nicolucci (Jollino)
Salvaguardia dell'italiano: http://www.nokappa.it
Photo portfolio: http://www.nicolucci.eu
Blog: http://www.flussodicoscienza.it