9 GPR - General Purpose Registers
The AVR64DA28/32/48/64 devices
provide four General Purpose Registers. These registers can be used for storing any
information, and they are particularly useful for storing global variables and interrupt
flags. General Purpose Registers, which reside in the address range 0x1C - 0x1F, are
directly bit-accessible using the SBI
, CBI
,
SBIS
, and SBIC
instructions.