I've spent this afternoon attempting to program an attiny85 I purchased a while ago with an arduino uno. It worked fine last night however I noticed the program didn't seem to be running completely smoothly the next morning so I tried to test the chip with the generic blink program, which is when problems began. I'm using the wiring diagram from:
And I have checked an endless amount of times the wiring is right. However after uploading the arduino ISP sketch to my uno, when I connect the attiny85 to the pins the yellow L light on the board goes off, and when I try to upload a sketch I get an invalid device signature error. Is this something I'm doing wrong or is the attiny bricked?
It worked at one time and now does not ?
One way of achieving this is to select the wrong board type and choose the burn boot loader option which sets the fuses to expect a non existing crystal oscillator.
Incidentally, the diagram here http://highlowtech.org/?p=1706 is a good example of a bad Fritzing diagram where important detail (pin numbers etc. are obscured) and a simple connections table would have been far more useful.
Are you programming your tiny on a solderless breadboard? This has given me problems on more than one occasion. If so, try wiggling the connections around a bit, or move to a different breadboard.
It seems like the wide shape of the pins on a pdip chip can spread the pinchers inside the breadboard to the point that thin wires don't always make good contact.