p89v51rb2 NXP Semiconductors, p89v51rb2 Datasheet - Page 19

• Manufacturer Part Number: p89v51rb2
• Description: 8-bit 80c51 5 V Low Power 16/32/64 Kb Flash Microcontroller With 1 Kb Ram
• Manufacturer: NXP Semiconductors

NXP Semiconductors
P89V51RB2_RC2_RD2_4
Product data sheet
6.2.8 Dual data pointers
The device has two 16-bit data pointers. The DPTR Select (DPS) bit in AUXR1
determines which of the two data pointers is accessed. When DPS = 0, DPTR0 is
selected; when DPS = 1, DPTR1 is selected. Quickly switching between the two data
pointers can be accomplished by a single INC instruction on AUXR1 (see
Fig 6. Internal and external data memory structure
2FFH
000H
2FFH
000H
EXPANDED RAM
ADDRESSING)
EXPANDED
(INDIRECT
768 B
RAM
Rev. 04 — 1 May 2007
FFFFH
0300H
FFH
7FH
80H
00H
INTERNAL RAM
INTERNAL RAM
(INDIRECT AND
ADDRESSING)
ADDRESSING)
ADDRESSING)
LOWER 128 B
UPPER 128 B
EXTRAM = 0
EXTERNAL
P89V51RB2/RC2/RD2
(INDIRECT
(INDIRECT
MEMORY
DIRECT
DATA
8-bit microcontrollers with 80C51 core
FFFFH
0000H
FFH
80H
REGISTERS (SFRs)
ADDRESSING)
ADDRESSING)
EXTERNAL
FUNCTION
(INDIRECT
EXTRAM = 1
MEMORY
SPECIAL
(DIRECT
DATA
© NXP B.V. 2007. All rights reserved.
Figure
002aaa517
7).
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