Problem using an Arduino Uno as an ISP to program an ATtiny85-20SU SOIC-8

Hi Guys,

I know this is a little bit of a noob-ish question, but here it goes.

I am running Arduino IDE 1.6.7 and wrote a simple program for an Attiny85. It is hooked up to the below schematic. If the Attiny85 is the PDIP-8, ATtiny85-20PU, it programs without any issues and does what I tell it to. However, with the exact same schematic, but with an ATtiny85-20SU (Mouser Part), I get an error.

avrdude: please define PAGEL and BS2 signals in the configuration file for part ATtiny85
avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override

I know the first message is normal for the David A. Mellis attiny stuff, but the second error I am not as familiar with.

I guess I am to use -F or something to specify the avrdude to work on an Attiny85-20SU instead of a PU, but I don’t know how to do that.

Anyone know how?

Thanks for any help,

When programming the Attiny how do you power it ?In your schematic i assume j2 is the isp header but only 5 pins connected.I work with an Attiny85-SO SMD(not an expert , still learning) and it works just like the dip. My guess is that something is wrong with your connections. Hope i could help.Maybe others will have other ideas,there are a lot of experts on this forum. ;)

Oops. Sorry, I forgot to explain that. The ignition signal is a 12V supply source, which after it leaves U1, it becomes 5V. I also remove the jumper shunt on JP1, so that basically the attiny85 is isolated from anything that could goof up the programming.


Do the different chips happen to have different signatures, as they do with the ATmega328 versions?

Hi Paul,

I believe from that error message, that they do. However, I am not exactly sure in the Arduino IDE, how to tell it what the "right signature" is.

That may be what I am trying to ask.


Hmmm. In the datasheet, I find only one version of the signature as 0x1e 0x93 0x0b, however avrdude.conf (/usr/share/arduino/hardware/tools/avrdude.conf) also mentions 0x1E 0x93 0x08, so I cannot pick why!

Try this in avrdude avrdude -c "your programmer" -B 50 -p t85 -v -v -v -v It should try to find the mcu without flashing or doing anything and maybe the -B option helps(slows SCK for 1mhz chips).

Thanks Andrei112, will try today and let you all know.

So, I got another ATtiny85-20SU and it works fine with that one. So, I guess the issue was with just getting a DOA chip the first time. Thanks for all the help!