8051 Pin Diagram

8051 Pin Diagram & Description

 

Pin Description:

Pin	Name	Description
40	Vcc	Active High Input. Power Supply. Usually +5V.
32 – 39	P0.0 – P0.7	Bi-directional IO port. Bit/Byte addressable.
	AD0 – AD7	Data bus and lower order address bus for external memory interfacing.
31	EA	Active Low Input. External Access input is used to enable or disable external memory interfacing.
	Vpp	Programming Voltage
30	ALE	Active High Output. Address Latch Enable is used to de-multiplex address and data signal of port 0.
	PROG	Program pulse input during EPROM/ROM programming.
29	PSEN	Active Low Input. Program Store Enable is used to read signal from external program memory.
21 - 28	P2.0 – P2.7	Bi-directional IO port. Bit/Byte addressable.
	A8 – A15	Address bus for external memory interfacing.
20	Vss	Power Supply Ground. 0V.
18 – 19	XTAL	Inputs for on-chip oscillator and clock generator circuit.
17	P3.7	Bi-directional IO pin.
	RD	Active Low Output. External memory Read control signal.
16	P3.6	Bi-directional IO pin.
	WR	Active Low Output. External memory Write control signal.
15	P3.5	Bi-directional IO pin.
	T1	External input to Timer 1.
14	P3.4	Bi-directional IO pin.
	T0	External input to Timer 0.
13	P3.3	Bi-directional IO pin.
	INT1	Input. External interrupt source.
12	P3.2	Bi-directional IO pin.
	INT0	Input. External interrupt source.
11	P3.1	Bi-directional IO pin.
	TxD	Output. Transmits serial data.
10	P3.0	Bi-directional IO pin.
	RxD	Input. Received serial data.
9	Reset	Reset Input.
1 – 8	P1.0 – P1.7	Bi-directional IO port. Bit/Byte addressable.

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Related topics:
8051 History   |   8051 Features   |   8051 Architecture   |   8051 Memory Types   |   8051 Memory Map

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