Figure 1. I/O Direct Addressing
Operand address is contained in six bits of the instruction word. n is the destination or source register address.
Note: Some complex AVR Microcontrollers have more peripheral units than can be supported within
the 64 locations reserved in the opcode for I/O direct addressing. The extended I/O memory
from address 64 to 255 can only be reached by data addressing, not I/O addressing.