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.
- - - - -
DPSEL(92 H)
DPSEL
.2
0
0
0
0
1
1
1
1
.1
0
0
1
1
0
0
1
1
.0
0
1
0
1
0
1
0
1
.2 .1 .0
DPTR7
Selected
Data-
pointer
DPTR 0
DPTR 1
DPTR 2
DPTR 3
DPTR 4
DPTR 5
DPTR 6
DPTR 7
External Data Memory
MCD00779
DPTR0
DPH(83 H )
DPL(82 H)
Figure 8
External Data Memory Addressing using Multiple Datapointers
Semiconductor Group
20
1997-07-01