SyncMOS Technologies Inc.
May 2001
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)
02FF
Expanded 768 bytes (Accessed
by
direct external addressing
mode,
by instruction MOVX)
(OME = 1)
FF
80
FF
SFR (Accessed by direct
addressing mode only)
Higher 128 bytes (Access by
indirect addressing mode only)
80
7F
Lower 128 bytes (Accessed by
addressing mode)
direct & indirect
0000
00
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).
Internal RAM Control Register (RCON, $85)
bit-7
Unused
*
bit-0
RAMS0
Read :
Write :
Reset value :
Unused
*
Unused
*
Unused
*
Unused
*
Unused
*
RAMS1
0
0
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 [ SYNCMOS TECHNOLOGIES,INC ]
