Original Publication Date: 1981-Nov-01
Included in the Prior Art Database: 2005-Feb-12
The drawing shows a keyboard 2 having an array of key-operated switches 3, 4. Each switch is connected between a row wire X1...Xn and a column wire Y1...Yn. The circuit of the drawing scans the row and column wires and produces an output on a line 5 that identifies a switch that has been closed. For the scanning operation, each row or column wire is driven by an AND Invert (AI) gate.