I'm attempting to transfer over an Arduino Uno project to an ATTiny85. I have the blink example working, but when I try my project it doesn't quite work correctly. (I'm using Arduino as an ISP).
The circuit is the ATTiny driving 3 74HC595 registers chained together to control 20 LED's. The power source is a CR2032 cell, but I've also tried it from the Arduino's 3V supply. What happens is that the shift registers light up the LED's in completely the wrong order, sometimes flickering. There doesn't seem to be any logic behind how it's driving the registers it's driving.
Am I missing something obvious? I thought the internal clock speed (I've tried 1Mhz and 8Mhz), same result.
Any advice or ideas is welcome!