May 2001

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

6/19

Ver 1.3

PID 89516 05/01

SyncMOS Technologies Inc.

SM89516

Data Memory

The SM89516 has 1K bytes on-chip RAM, 256 bytes of it are the same as general 8052 internal memory

structure while the expanded 768 bytes on-chip RAM can be accessed by external memory addressing method.

(by instruction MOVX)

FF

80

7F

00

FF

80

Expanded 768 bytes (Accessed

direct external addressing

by instruction MOVX)

02FF

0000

Data Memory - Lower 128 byte

Data memory $00 to $FF is the same as 8052

The address $00 to $7F can be accessed by direct and indirect addressing modes.

Address $00 to $1F is register area.

Address $20 to $2F is memory bit area.

Address $30 to $7F is for general memory area.

Data memory - Higher 128 byte

The address $80 to $FF can be accessed by indirect addressing mode only.

Addressing $80 to $FF is data area.

Data Memory - Expanded 768 bytes

From external address $0000 to $02FF is the on-chip expanded RAM area, total 768 bytes. This area can be

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

Higher 128 bytes (Access by

indirect addressing mode only)

SFR (Accessed by direct

addressing mode only)

Lower 128 bytes (Accessed by

direct & indirect

by

mode,

addressing mode)

(OME = 1)

Internal RAM Control Register (RCON, $85)

bit-7

bit-0

Read :

Unused

Unused

Unused

Unused

Unused

Unused

RAMS1

RAMS0

Write :

Reset value :

******

0

0