I'm trying to use an ATtiny85 to charleplex some LEDs, and using a hardware timer to generate PWM for a 'fade up / fade down' effect. Code attached.
Randomly, there's an initial "blip" pulse of random length before the correct pulse train starts when enabling PWM. The blip measures from 0 to 2.040 ms in length. This is causing a quick strobe (flash) before the LED is 'fading' up.
What's causing this blip?