SAB80C517A-N18 Siemens Semiconductor Group, SAB80C517A-N18 Datasheet - Page 26

• Manufacturer Part Number: SAB80C517A-N18
• Description: 8-Bit CMOS Single-Chip Microcontroller
• Manufacturer: Siemens Semiconductor Group

Multiple Datapointers
As a functional enhancement to standard 8051 controllers, the SAB 80C517A contains eight
16-bit datapointers. The instruction set uses just one of these datapointers at a time. The
selection of the actual datapointer is done in special function register DPSEL (data pointer
select, addr. 92
Figure 3
Addressing of External Data Memory
Semiconductor Group
DPSEL(92 )
DPSEL
-
.2
0
0
0
0
1
1
1
1
-
.1
0
0
1
1
0
0
1
1
-
H
H
). Figure 3 illustrates the addressing mechanism.
-
.0
0
1
0
1
0
1
0
1
-
Selected
Data-
pointer
DPTR 0
DPTR 1
DPTR 2
DPTR 3
DPTR 4
DPTR 5
DPTR 6
DPTR 7
.2
.1
.0
DPH(83 )
H
25
DPL(82 )
H
DPTR7
DPTR0
SAB 80C517A/83C517A-5
External Data Memory
MCD00779
1994-05-01