SM5964B
8-Bit Micro-controller
64KB with ISP Flash
& 1KB RAM embedded
3.2 Data Memory
The SM5964B 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.
02FF
Expanded 768 Bytes
(Accessed by direct
external addressing mode
by instruction MOVX)
FF
FF
80
Higher 128 Bytes (Accessed by
indirect addressing mode only)
SFR (Accessed by direct addressing
mode only)
80
7F
Lower 128 Bytes (Accessed by
direct & indirect addressing mode )
00
0000
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
System
Configuration
Register
Dir.
Bit 7
Bit 6
Expanded RAM
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
PDWU
E
SCONF
BFh
WDR
-
-
-
ISPE
OME
ALEI
02H
Internal RAM
Control Register
Data Bank
RAMS
1
RAMS
0
RCON
85h
86h
-
-
-
-
-
-
-
-
-
00H
01H
DBANK
BSE
BS3
BS2
BS1
BS0
Control Register
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M081 Ver A SM5964B 3/7/2014
- 18 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
