Data Pointer - Siemens C500 User Manual

2.5

Data Pointer

8-bit accesses to the internal XRAM data memory or the external data memory are executed using
the data pointer DPTR as an 16-bit address register. Normally, the C500 family microcontrollers
have one data pointer. But some members of the C500 family provide eight data pointers. The
availability of eight data pointers especially supports the programming in high level languages which
have a demand to store data in large external data memory portions.
Special Function Register DPL (Address 82 H )
Special Function Register DPH (Address 83 H )
Special Function Register DPSEL (Address D0 H )
MSB
Bit No.
7
82 H .7
83 H MSB
92 H Ð
Bit Function
Ð Reserved bits for future use
DPSEL.2 - 0 Data pointer select bits
DPSEL.2-0 defines the number of the actual active data pointer.DPTR0-7.
Semiconductor Group
6 5
.6 .5
.6 .5
Ð Ð
DPSEL2 DPSEL1 DPSEL0 Function
0 0
0 0
0 1
0 1
1 0
1 0
1 1
1 1
4 3 2
.4 .3 .2
.4 .3 .2
Ð Ð .2
0 Data pointer 0 selected
1 Data pointer 1 selected
0 Data pointer 2 selected
1 Data pointer 3 selected
0 Data pointer 4 selected
1 Data pointer 5 selected
0 Data pointer 6 selected
1 Data pointer 7 selected
2-4
CPU Functions
C500 Family
Reset Value : 00 H
Reset Value : 00 H
Reset Value : 00 H
LSB
1 0
.1 LSB DPL
.1 .0 DPH
.1 .0 DPSEL
1998-04-01