TS80C54_14 Datasheet, PDF (11/62 Pages) ATMEL Corporation – Programmable Clock Out and Up/Down Timer/Counter 2

AT/TS8xC54/8X2
7. Dual Data Pointer Register Ddptr
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 external data
memory location. There are two 16-bit DPTR registers that address the external memory, and a
single bit called
DPS = AUXR1/bit0 (See Table 7-1.) that allows the program code to switch between them
(Refer to Figure 7-1).
Figure 7-1. Use of Dual Pointer
External Data Memory
7
0
DPS
AUXR1(A2H)
DPTR1
DPTR0
DPH(83H) DPL(82H)
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4431E–8051–04/06