I am using an Arduino as ISP to program Attiny chips at 8Mhz (internal). I am using the Arduino IDE as I find this easier. Some of the chips I was programming however appeared to be working at 1Mhz instead of 8Mhz. After pulling my hair out for 30 minutes thinking it was random, I realised that they have different numbers on them (Both Attiny85-20PU) but one had 1512 (works properly) and one has 1822 (does not work properly). They are both from ATMEL.
What is this number, and also how can I get around this?
Best Answer
That's the date code. "1822" is a misread since that date is in the future. You can get around this by unprogramming the CKDIV8 fuse which comes programmed from the factory.