ATmega88PA Automotive Atmel Corporation, ATmega88PA Automotive Datasheet - Page 18

• Manufacturer Part Number: ATmega88PA Automotive
• Manufacturer: Atmel Corporation

8.3
18
SRAM Data Memory
Atmel ATmega48PA/88PA/168PA [Preliminary]
Figure 8-3
The Atmel ATmega48PA/88PA/168PA is a complex microcontroller with more peripheral units
than can be supported within the 64 locations reserved in the Opcode for the IN and OUT
instructions. For the Extended I/O space from 0x60 - 0xFF in SRAM, only the ST/STS/STD
and LD/LDS/LDD instructions can be used.
The lower 768/1280/1280/2303 data memory locations address both the Register File, the I/O
memory, Extended I/O memory, and the internal data SRAM. The first 32 locations address
the Register File, the next 64 location the standard I/O memory, then 160 locations of
Extended I/O memory, and the next 512/1024/1024/2048 locations address the internal data
SRAM.
The five different addressing modes for the data memory cover: Direct, Indirect with Displace-
ment, Indirect, Indirect with Pre-decrement, and Indirect with Post-increment. In the Register
File, registers R26 to R31 feature the indirect addressing pointer registers.
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 Z-register.
When using register indirect addressing modes with automatic pre-decrement and post-incre-
ment, the address registers X, Y, and Z are decremented or incremented.
The 32 general purpose working registers, 64 I/O Registers, 160 Extended I/O Registers, and
the 512/1024/1024/2048 bytes of internal data SRAM in the Atmel ATmega48PA/88PA/168PA
are all accessible through all these addressing modes. The Register File is described in
eral Purpose Register File” on page
Figure 8-3.
shows how the Atmel
Data Memory Map
(512/1024/1024/2048 x 8)
64 I/O Registers
160 Ext I/O Reg.
Data Memory
Internal SRAM
32 Registers
®
ATmega48PA/88PA/168PA SRAM Memory is organized.
11.
0x02FF/0x04FF/0x4FF/0x08FF
0x0000 - 0x001F
0x0020 - 0x005F
0x0060 - 0x00FF
0x0100
9223B–AVR–09/11
“Gen-