Method of Testing a Keyboard Controller on a Computer Without Involving the Operator
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
A method is described to test a computer keyboard controller on each power-on without requiring key depression by the operator. The IBM Convertible Personal Computer utilizes reduced logic in the keyboard controller to save space and power. In previous personal computers a dedicated CPU is used as the keyboard controller with additional logic to scan all key positions and detect key changes. Diagnostics usually require that each key be depressed by the operator and visually verified by depiction of the depressed key on the display. The keyboard controller in the IBM Convertible has no dedicated processor. Instead, it consists of logic to sequentially drive each column line on the keyboard and sense each row line coming back from the keyboard.