SoftwareSerial magic numbers

robtillaart:
Have you tried AltSoftSerial on a 1Mhz ATTINY as that is what Robin is looking for?

Oh, no, I haven't tried it, but I'm pretty sure it won't work. Most ATTINY chips have only 8 bit timers. AltSoftSerial needs a 16 bit timer with input capture and 2 compare units.