I got 8 led in a charlieplexing config using 4 outputs of the ATTiny85. I let 1 led glow up and the previous one glow down and make a round for a small lighthouse. I want this to happen in 8 seconds for all leds. So one cycle takes up 8000 millisec / 8 led / 64 steps.
The interrupt is handeling the values and order set in the loop.
I don't get the timing right. The board is running at 8Mhz.
So one cycle should be 8000/8/64 = 15 millisec. But when i put in a delay of 15 it runs to fast. It needs to be 1800. Don't understand why.
Thanks for looking into it.