Datasheet

The direct addressing reaches the entire data space.

The Indirect with Displacement mode reaches 63 address locations from the base address given by the

Y- or Zregister.

When using register indirect addressing modes with automatic pre-decrement and post-increment, the

address registers X, Y, and Z are decremented or incremented.

The 32 general purpose working registers, 64 I/O registers, and the 4096 bytes of internal data SRAM in

the Atmel AVR ATmega64A are all accessible through all these addressing modes. The Register file is

described in General Purpose Register File.

Figure 12-2 Data Memory Map

Me mo ry Co nfiguration B

32 Registers

64 I/O Regis ters

Interna l S RAM

(4000 x 8)

$0000 - $001F

$0020 - $005F

$1000

$0FFF

$FFFF

$0060

Data Memory

Exte rnal S RAM

(0 - 64K x 8)

Me mo ry Co nfiguration A

32 Registers

64 I/O Regis ters

Interna l S RAM

(4096 x 8)

$0000 - $001F

$0020 - $005F

$1100

$10FF

$FFFF

$0060 - $00FF

Data Memory

Exte rnal S RAM

(0 - 64K x 8)

160 Ext I/O Re g.

$0100