Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

PIN HANEL

DESCRIPTION

Port 0(cont’)

‰It can be used for input or output, each pin must be connected externally to a 10K ohm pull-up resistor

¾This is due to the fact that P0 is an open drain, unlike P1, P2, and P3

ƒOpen drain is a term used for MOS chips in the same way that open coll

ector is used for TTL

chips

Vcc P0.0P0.1P0.2P0.3P0.4P0.5P0.6P0.7

10 K

8051/52

Port 0

P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7RST(RXD)P3.0(TXD)P3.1(INT0)P3.2(INT1)P3.3(T0)P3.4(T1)P3.5(WR)P3.6(RD)P3.7XTAL2XTAL1GND

VccP0.0(AD0)P0.1(AD1)P0.2(AD2)P0.3(AD3)P0.4(AD4)P0.5(AD5)P0.6(AD6)P0.7(AD7)-EA/VPPALE/PROG-PSENP2.7(A15)P2.6(A14)P2.5(A13)P2.4(A12)P2.3(A11)P2.2(A10)P2.1(A9)P2.0(A8)

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(^40393837363534333280513130) (8031) 292827262524232221