sylvandb/ArduinoISP — comment on commit a5d34dfde4675dd82792da6efc2f8dbcd2ac81a6
File:  line 0
By rsbohn:

Could you use pin 3,5, or 6 for this? Then you wouldn't need to remap pin 9.
I think you'd get the same result using analogWrite(CLOCK_PIN, 128);