mpc82g516a Megawin Technology, mpc82g516a Datasheet - Page 35

• Manufacturer Part Number: mpc82g516a
• Description: 8-bit Microcontroller
• Manufacturer: Megawin Technology

9 Dual Data Pointer Register (DPTR)
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 external data memory location. There are two
16-bit DPTR registers that address the external memory, and a single control bit called DPS (AUXR1.0) that
allows the program code to switch between the external memory.
Figure 9-1. Use of Dual DPTR
DPTR Instructions
The six instructions that refer to DPTR currently selected using the DPS bit are as follows:
AUXR1 (Address=8EH, Auxiliary Register1, Reset Value=0000,0000B)
DPS: DPTR select bit, used to switch between DPTR0 and DPTR1.
The DPS bit status should be saved by software when switching between DPTR0 and DPTR1.
35
INC
MOV
MOVC A,@A+DPTR
MOVX A,@DPTR
MOVX @DPTR,A
JMP
P4KB
7
DPTR
DPTR,#data16 ;Loads the DPTR with a 16-bit constant
@A+DPTR
DPTR0
DPTR1
P4PCA
6
DPS
0
1
(83h)
DPH
DPH
P4SPI
5
;Increments the data pointer by 1
;Move code byte relative to DPTR to ACC
;Move external RAM (16-bit address) to ACC
;Move ACC to external RAM (16-bit address)
;Jump indirect relative to DPTR
(82h)
DPL
DPL
DPTR selected
P4S2
4
DPTR0
DPTR1
MPC82G516A Data Sheet
Selected by
DPS=0
DPS=1
GF2
3
DPS
2
-
1
External Data Memory
-
DPS
0
MEGAWIN