Keyboard crosspoint encoder having pseudo-n-key rollover

Claim 2

In a crosspoint encoder device, an improved method for the detection and solution of phantom key problems comprising the steps of: (a) scanning rows and columns of an encoder matrix to determine a status of each switch in said matrix; (b) creating a keystroke event buffer to store successive changes in said crosspoint switch status by storing said changes sequentially in order of occurrence; (c) analyzing accumulated data in said event buffer for an existence of a phantom condition; (d) halting the reporting of data to an object device when said phantom condition is detected; (e) continuing to record incoming data and retaining such data in said event buffer until said phantom condition no longer exists; (f) reporting a corrected data stream in an order recorded to said object device when said phantom condition ceases to exist; whereby actual switch changes are presented correctly in the order of their occurrence.

Claim 3

The method of claim 1, wherein the step of analyzing said existence of said condition comprises the steps of: (a) selecting a first key down event from said event buffer; (b) comparing matrix coordinates, having a first and a second coordinate number of said first selected key down event with those of each other key down event in said buffer; (c) selecting second key down event having a same second coordinate number as said first selected key down event; (d) comparing matrix coordinates of said second selected key down event with those of all other key down events in said buffer; and, (e) identifying an existence of said phantom condition whenever another key down event in said buffer has a same first coordinate as said second selected key down event.

Claim 4

The method of claim 2, wherein said first coordinate number is a row number and said second coordinate number is a column number of said matrix.

Claim 5

The method of claim 2, wherein said crosspoint encoder device is of a type having a plurality of electrical switching elements arranged in a matrix of rows and columns.

Claim 6

The method of claim 1, wherein in the step (f), a corrected data stream is reported up to a possible second phantom condition when said first phantom condition ceases to exist.

Claim 7

In a crosspoint encoder device having a plurality of electrical switching elements arranged in a row and column matrix, an improved method for solving a phantom key condition, comprising the steps of: (a) scanning rows and columns of said matrix to determine a state of each of said switching element; (b) storing state changes of said switching elements in a storage buffer as events in the order of their occurrence; (c) selecting a first event from said buffer by recording every key down event in the order of occurrence; (d) comparing matrix coordinates, having a first and a second coordinate number, of said first selected event with those of all events stored in said buffer; (e) selecting a second event having a same second coordinate number as said first selected event; (f) comparing matrix coordinates of said second selected event with those of all other events stored in said buffer; (g) identifying an existence of said phantom key condition whenever another event in said buffer has a same first coordinate number as said second selected event; (h) continuing to store incoming switch state changes in said buffer until said phantom condition no longer exists; (i) reporting said events present in said buffer after removal of said phantom condition; (j) repeating steps (c) through (g) until said events in said buffer have processed for phantom conditions up to a point where a subsequent phantom condition is detected; whereby actual switch changes are presented correctly in the order of their occurrence.

Claim 8

In a crosspoint encoder device having a plurality of electrical switching elements arranged in a row and column matrix, an improved method for solving a phantom key condition, comprising the steps of: (a) scanning rows and columns of said matrix to determine a state of each of said switching element; (b) storing state changes of said switching elements in a storage buffer as events in the order of their occurrence; (c) selecting a first event from said buffer by recording every key down event in the order of occurrence; (d) comparing matrix coordinates, having a first and a second coordinate number, of said first selected event with those of all events stored in said buffer; (e) selecting a second event having a same second coordinate number as said first selected event; (f) comparing matrix coordinates of said second selected event with those of all other events stored in said buffer; (g) identifying an existence of said phantom key condition whenever another event in said buffer has a same first coordinate number as said second selected event; (h) continuing to store incoming switch state changes in said buffer until said phantom condition no longer exists; (i) reporting said events present in said buffer after removal of said phantom condition; (j) repeating steps (c) through (g) until said events in said buffer have processed for phantom conditions up to a point where a subsequent phantom condition is detected; whereby actual switch changes are presented correctly in the order of their occurrence.

Claim 9

The method of claim 6, wherein said first number is a row number and said second coordinate number is a column number of said matrix.