Switch matrix encoding interface using common input/output parts

Abstract

An encoding interface is provided between input data ports and strobe output ports of a (semiconductor integrated) circuit (chip) and an array of switches (40) is connected to a series of L input data lines and output lines (31-38), whereby the L lines can alternatively strobe the switch matrix to determine the (50) position of each switch. By having each line function either as an input line or an output line at a particular instant of time, the number of switches being served by a fixed number of total input and output lines is increased. For example, with eight total lines 28 switches are accommodated when the lines function either as input or output lines while when four separate lines are dedicated as input lines and four other lines dedicated as output lines only 16 switches are accommodated. In a further embodiment using two switches and a pair of oppositely disposed diodes at each cross point in the matrix the number of switches can be doubled (to 56 with eight dual input/output lines).