Datasheet

AT89C51RB2/RC2

4180D–8051–06/05

Dual Data Pointer

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 17) that allows the program

code to switch between them (see Figure 7).

Figure 7. Use of Dual Pointer

External Data Memory

AUXR1(A2H)

DPS

DPH(83H) DPL(82H)

DPTR0

DPTR1