SyncMOS Technologies Inc.
July 2002
SM5964
02FF
Expanded 768 byte (Accessed
by direct external addressing
mode, by instruction MOVX)
FF
(OME = 1)
FF
Higher 128 byte (Accessed by
80
indirect addressing mode only)
7F
SFR (Accessed by direct
addressing mode only)
80
0000
Lower 128 byte (Accessed by
00
direct & indirect addressing mode)
1.2.1 Data Memory - Lower 128 byte ($00 to $7F, Bank 0 & Bank 1)
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.
1.2.2 Data Memory - Higher 128 byte ($80 to $FF, Bank 2 & Bank 3)
The address $80 to $FF can be accessed by indirect addressing mode or by bank mapping direct addressing mode.
Address $80 to $FF is data area.
1.2.3 Data Memory - Expanded 768 bytes ($0000 to $02FF, Bank 4 ~ Bank 15)
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 (by instruction MOVX) or by bank mapping direct addressing mode.
If the address of instruction MOVX @DPTR is larger than $02FF then SM5964 will generate the external memory control
signal automatically. The bit 1 (OME) of special function register $BF (SCONF) can enable or disable this expanded 768
byte RAM. The default setting of OME bit is 1 (enable).
The address space of instruction MOVX @Ri, i=0,1 is determined by bit 1 & bit 0 (RAMS1, RAMS0) of special function reg-
ister $85 (RCON). The default setting of RAMS1, RAMS0 bits is 00 (page0).
One page of data RAM is 256 byte.
RAMS1, RAMS0=00, Rn of instruction MOVX @Ri, i=0,1 mapping to expanded RAM address $0000 to $00FF (page 0)
RAMS1, RAMS0=01, Rn of instruction MOVX @Ri, i=0,1 mapping to expanded RAM address $0100 to $01FF (page 1)
RAMS1, RAMS0=10, Rn of instruction MOVX @Ri, i=0,1 mapping to expanded RAM address $0200 to $02FF (page 2)
RAMS1, RAMS0=11, Rn of instruction MOVX @Ri, i=0,1 mapping to expanded RAM address $XY00 to $XYFF which high
byte address specified by port 2. (SM5964 will generate the external memory control signal automatically).
Specifications subject to change without notice,contact your sales representatives for the most recent information.
7/28
Ver 1.0
PID 5964 07/02
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
