Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

BIT HANEL

ADDRESSESI/O Port Bit Addresses

(cont’)

‰Notice that when code such as SETB P1.0

is assembled, it becomes

SETB 90H¾The bit address for I/O ports

ƒP0 are 80H to 87H ƒP1 are 90H to 97HƒP2 are A0H to A7HƒP3 are B0H to B7H

P2P2.0 (A0)P2.1P2.2P2.3P2.4P2.5P2.6(A7)P2.7

P3P3.0 (B0)P3.1P3.2P3.3P3.4P3.5P3.6(B7)P3.7

P1P1.0 (90)P1.1P1.2P1.3P1.4P1.5P1.6(97)P1.7

P0P0.0 (80)P0.1P0.2P0.3P0.4P0.5P0.6(87)P0.7

Port BitD0D1D2D3D4D5D6D7

Single-Bit Addressability of Ports