AT90LS8535-4MC View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT90LS8535-4MC

8-Bit AVR® Microcontroller with 4K/8K Bytes In-System Programmable Flash

Atmel Corporation 

SRAM Data Memory

AT90S/LS8535

Figure 8 shows how the AT90S8535 SRAM memory is organized.

Figure 8. SRAM Organization

Register File

R0

R1

R2

...

Data Address Space

$0000

$0001

$0002

...

R29

R30

R31

I/O Registers

$00

$01

$02

...

$001D

$001E

$001F

$0020

$0021

$0022

...

$3D

$005D

$3E

$005E

$3F

$005F

Internal SRAM

$0060

$0061

...

$025E

$025F

The lower 608 data memory locations address the Register file, the I/O memory and the

internal data SRAM. The first 96 locations address the Register file + I/O memory, and

the next 512 locations address the internal data SRAM.

The five different addressing modes for the data memory cover: Direct, Indirect with Dis-

placement, 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 features 63 address locations reached from the

base address given by the Y- or Z-registers.

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

increment, the address registers X, Y, and Z are decremented and incremented.

The 32 general-purpose working registers, 64 I/O registers and the 512 bytes of internal

data SRAM in the AT90S8535 are all accessible through all these addressing modes.

See the next section for a detailed description of the different addressing modes.

11

1041H–11/01

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