SM89516B datasheet(18/49 Pages) SYNCMOS

18 / 49 page

SM89516B

8-Bit Micro-controller

64KB Flash

& 1KB RAM embedded

Specifications subject to change without notice contact your sales representatives for the most recent information.

ISSFD-M087

Ver D SM89516B 08/07/2015

- 18 -

3.2

Data Memory

The SM89516B has 256B +768B on-chip SRAM. 256B of it are the same as general 8052 internal memory

structure while the expanded 768 Bytes on-chip SRAM can be accessed by external memory addressing method

( by instruction MOVX). As shown in Fig. 3-2.

Higher 128 Bytes (Accessed by

indirect addressing mode only)

Lower 128 Bytes (Accessed by

direct & indirect addressing mode )

SFR (Accessed by direct addressing

mode only)

Expanded 768 Bytes

(Accessed by direct

external addressing mode

by instruction MOVX)

0000

02FF

Fig. 3-2: RAM architecture

3.3

Data memory - lower 128 byte (00h to 7Fh)

Data memory 00h to FFh is the same as 8052.

The address 00h to 7Fh can be accessed by direct and indirect addressing modes.

Address 00h to 1Fh is register area.

Address 20h to 2Fh is memory bit area.

Address 30h to 7Fh is for general memory area.

3.4

Data memory - higher 128 byte (80h to FFh)

The address 80h to FFh can be accessed by indirect addressing mode.

Address 80h to FFh is data area.

3.5

Data memory - Expanded 768 bytes ($0000 to $02FF)

From external address 0000h to 02FFh is the on-chip expanded SRAM area, total 768 Bytes. This area can be

accessed by external direct addressing mode (by instruction MOVX).

Mnemonic

Description

Dir.

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

RST

Expanded RAM

SCONF

System

Configuration

BFh

WDR

PDWU

OME

ALEI

02H

RCON

Internal RAM

Control Register

85h

RAMS

00H

DBANK

Data Bank

Control Register

86h

BSE

BS3

BS2

BS1

BS0

01H

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