82C55A Datasheet, PDF (7/23 Pages) Intel Corporation – CHMOS PROGRAMMABLE PERIPHERAL INTERFACE

82C55A
Operating Modes
Mode 0 (Basic Input Output) This functional con-
figuration provides simple input and output opera-
tions for each of the three ports No ‘‘handshaking’’
is required data is simply written to or read from a
specified port
Mode 0 Basic Functional Definitions
 Two 8-bit ports and two 4-bit ports
 Any port can be input or output
 Outputs are latched
 Inputs are not latched
 16 different Input Output configurations are pos-
sible in this Mode
MODE 0 (BASIC INPUT)
MODE 0 (BASIC OUTPUT)
231256 – 8
231256 – 9
7