TS80C51RA2 Atmel Corporation, TS80C51RA2 Datasheet - Page 13

• Manufacturer Part Number: TS80C51RA2
• Description: High Performance 8-bit Microcontroller
• Manufacturer: Atmel Corporation

Dual Data Pointer
Register
Figure 3. Use of Dual Pointer
4188A–8051–10/02
7
AUXR1(A2H)
DPS
0
The additional data pointer can be used to speed up code execution and reduce code
size in a number of ways.
The dual DPTR structure is a way by which the chip will specify the address of an exter-
nal data memory location. There are two 16-bit DPTR registers that address the external
memory, and a single bit called DPS = AUXR1/bit0 (Table 4) that allows the program
code to switch between them (Refer to Figure 3).
Table 4. AUXR1: Auxiliary Register 1
1.
2.
Address 0A2H
Symbol
AUXR1
DPS
GF3
-
User software should not write 1s to reserved bits. These bits may be used in future 8051
GF3 will not be available on first version of the RC devices.
DPH(83H) DPL(82H)
family products to invoke new feature. In that case, the reset value of the new bit will
be 0, and its active value will be 1. The value read from a reserved bit is
indeterminate.
Function
Not implemented, reserved for future use
Data Pointer Selection.
This bit is a general purpose user flag
Reset value
DPTR1
DPS
0
1
DPTR0
Operating Mode
DPTR0 Selected
DPTR1 Selected
-
X
-
X
(2)
.
-
X
(1)
External Data Memory
-
X
GF3
0
TS8xC51Rx2
-
X
-
X
DPS
0
13