The 8051 Microcontroller and Embedded

Department of Computer Scien

ce and Information Engineering

National Cheng Kung University, TAIWAN

HANEL

PROGRAMMING THE 8255Mode Selection

of 8255(cont’)

2. Mode 1ƒPort A and B can be used as input or output ports with handshaking capabilitiesƒHandshaking signals are provided by the bits of port C


3. 
   

   Mode 2ƒPort A can be used as a bidirectional I/O port with handshaking capabilities provided by port C ƒPort B can be used either in mode 0 or mode^1

   
   


4. 
   

   BSR (bit set/reset) modeƒOnly the individual bits of port C can be programmed