Vcc

Vss

XTAL1

XTAL2

RST/VPD

ALE/PROG reverse

EA/Vpp

PSEN anti

Arithmetic/logical operation unit ALU

Accumulator ACC

Register B

scratchpad

Program status word register PSW

Program CounterPC

Instruction register IR

Decoding and control logic

data pointer DPTR

Stack pointer SP

When the EA pin is connected to high level, instructions are fetched from the on-chip program memory.

When the EA pin is connected to low level, instructions are fetched from the off-chip program memory.

0000H: MCU reset entry address;

0003H: Interrupt service routine entry address of external interrupt 0

000BH: Timer/Counter 0 overflow interrupt service routine entry address

0013H: Interrupt service routine entry address of external interrupt 1;

001BH: Timer/Counter 1 overflow interrupt service routine entry address;

0023H: Serial port interrupt service routine entry address;

002BH: Enhanced microcontroller timer/counter 2 overflow or T2EX negative transition interrupt service program entry address

When the P0 port is used as a general-purpose I/O port, it is a quasi-bidirectional port. read, modify, write

Used as address/data bus (C=1) It's a true two-way mouth

It is used as a general-purpose I/O port and is a quasi-bidirectional port.

Used as address bus (c=1)

It is a general-purpose quasi-bidirectional I/O port.

When used as a general-purpose I/O port, it is a quasi-bidirectional port.

Use as a second function