C515C Datasheet, PDF (20/69 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C515C
Multiple Datapointers
As a functional enhancement to the standard 8051 architecture, the C515C contains eight 16-bit
datapointers instead of only one datapointer. The instruction set uses just one of these datapointers
at a time. The selection of the actual datapointer is done in the special function register DPSEL.
Figure 8 illustrates the datapointer addressing mechanism.
- - - - - .2 .1 .0
DPSEL(92 _H)
DPSEL
Selected
Data-
.2 .1 .0 pointer
0 0 0 DPTR 0
0 0 1 DPTR 1
0 1 0 DPTR 2
0 1 1 DPTR 3
1 0 0 DPTR 4
1 0 1 DPTR 5
1 1 0 DPTR 6
1 1 1 DPTR 7
DPTR7
DPH(83H) DPL(82H)
DPTR0
External Data Memory
MCD00779
Figure 8
External Data Memory Addressing using Multiple Datapointers
Semiconductor Group
20
1997-07-01