at89c51re2-slsem ATMEL Corporation, at89c51re2-slsem Datasheet - Page 18

• Manufacturer Part Number: at89c51re2-slsem
• Description: At89c51re2 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

Dual Data Pointer
Register DPTR
Figure 4. Use of Dual Pointer
18
AT89C51RE2
7
AUXR1(A2H)
The additional data pointer can be used to speed up code execution and reduce code
size.
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 = AUXR1.0 (see Table 16) that allows the program
code to switch between them (Refer to Figure 4).
DPS
0
DPH(83H) DPL(82H)
DPTR1
DPTR0
External Data Memory
7663B–8051–03/07