T89C51AC2-SLSIM View Datasheet(PDF) - Atmel Corporation

Part Name

Description

MFG CO.

T89C51AC2-SLSIM

Enhanced 8-bit Microcontroller with 32 KB Flash Memory

Atmel Corporation 

Prev 21 22 23 24 25 26 27 28 29 30 Next

Data Memory

A/T89C51AC2

The A/T89C51AC2 provides data memory access in two different spaces:

1. The internal space mapped in three separate segments:

• the lower 128 Bytes RAM segment.

• the upper 128 Bytes RAM segment.

• the expanded 1024 Bytes RAM segment (XRAM).

2. The external space.

A fourth internal segment is available but dedicated to Special Function Registers,

SFRs, (addresses 80h to FFh) accessible by direct addressing mode.

Figure 11 shows the internal and external data memory spaces organization.

Figure 10. Internal Memory - RAM

FFh

Upper

128 Bytes

Internal RAM

indirect addressing

80h

7Fh

Lower

128 Bytes

Internal RAM

direct or indirect

addressing

00h

FFh

Special

Function

Registers

direct addressing

80h

Figure 11. Internal and External Data Memory Organization XRAM-XRAM

FFFFh

64 KB

External XRAM

256 up to 1024 Bytes

Internal XRAM

EXTRAM = 0

00h

Internal

FFh or 3FFh

EXTRAM = 1

0000h

External

23

4127H–8051–02/08

Share Link: