P89C51RB2HBA NXP Semiconductors, P89C51RB2HBA Datasheet - Page 23

• Manufacturer Part Number: P89C51RB2HBA
• Manufacturer: NXP Semiconductors

Specifications of P89C51RB2HBA

• Cpu Family: 89C
• Device Core: 80C51
• Device Core Size: 8b
• Frequency (max): 33MHz
• Interface Type: UART
• Program Memory Type: Flash
• Program Memory Size: 16KB
• Total Internal Ram Size: 512Byte
• # I/os (max): 32
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• Instruction Set Architecture: CISC
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: PLCC
• Lead Free Status / Rohs Status: Not Compliant

Philips Semiconductors
Reduced EMI Mode
The AO bit (AUXR.0) in the AUXR register when set disables the
ALE output.
Reduced EMI Mode
AUXR (8EH)
AUXR.1
AUXR.0
Dual DPTR
The dual DPTR structure (see Figure 13) 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 that allows the program
code to switch between them.
AUXR1 (A2H)
Where:
The DPS bit status should be saved by software when switching
between DPTR0 and DPTR1.
The GF2 bit is a general purpose user-defined flag. Note that bit 2 is
not writable and is always read as a zero. This allows the DPS bit to
2002 May 24
New Register Name: AUXR1#
SFR Address: A2H
Reset Value: xxxxxxx0B
DPS = AUXR1/bit0 = Switches between DPTR0 and DPTR1.
80C51 8-bit Flash microcontroller family
16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM
7
–
7
–
6
–
6
–
Select Reg
DPTR0
DPTR1
EXTRAM
AO
ENBOOT
5
–
5
4
–
4
–
Turns off ALE output.
3
–
GF2
3
2
–
2
0
DPS
0
1
EXTRAM
1
1
–
DPS
AO
0
0
20
be quickly toggled simply by executing an INC AUXR1 instruction
without affecting the GF2 bit.
The ENBOOT bit determines whether the BOOTROM is enabled
or disabled. This bit will automatically be set if the status byte is
non zero during reset or PSEN is pulled low, ALE floats high, and
EA > V
cleared during reset.
DPTR Instructions
The instructions that refer to DPTR refer to the data pointer that is
currently selected using the AUXR1/bit 0 register. The six
instructions that use the DPTR are as follows:
The data pointer can be accessed on a byte-by-byte basis by
specifying the low or high byte in an instruction which accesses the
SFRs. See Application Note AN458 for more details.
INC DPTR
MOV DPTR, #data16
MOV A, @ A+DPTR
MOVX A, @ DPTR
MOVX @ DPTR , A
JMP @ A + DPTR
AUXR1
DPS
BIT0
IH
on the falling edge of reset. Otherwise, this bit will be
P89C51RB2/P89C51RC2/
(83H)
DPH
Increments the data pointer by 1
Loads the DPTR with a 16-bit constant
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
Figure 13.
(82H)
DPL
P89C51RD2Hxx
DPTR1
DPTR0
EXTERNAL
MEMORY
DATA
Product data
SU00745A