Atmel ATtiny25, ATtiny45 , ATtiny85 Datasheet ...
ATtiny25/45/85 [DATASHEET] 7 2586OS–AVR–02/13 4. Register Summary Note: 1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit...