Browse Prior Art Database

Keyboard Sensor Timing

IP.com Disclosure Number: IPCOM000082847D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Castle, WH: AUTHOR [+3]

Abstract

It is desirable from the cost standpoint to keep the number of sensors in an electronic keyboard to a minimum. Described is a method of eliminating the sensor associated with the timing of the data sensors.

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Keyboard Sensor Timing

It is desirable from the cost standpoint to keep the number of sensors in an electronic keyboard to a minimum. Described is a method of eliminating the sensor associated with the timing of the data sensors.

In Fig. 2, the six data sensors B1-B6 are logically ORed together at A to generate a signal KB STROBE. KB STROBE is used on the input to a delay circuit B with a minimum delay of about 2 ms.

The minimum delay is necessary to be sure that all data contacts are good before the generation of L STROBE.

L STROBE (Fig. 1) is the output of the delay circuit B and is used by the system logic as an indication that the keyboard sensors can be sampled.

The keyboard sensors are good for a minimum period of time after the generation of L STROBE, but not for the complete duration of L STROBE. It is necessary for the system logic to sample within the time period that the contacts are good. This time is on the order of 6 to 10 ms, and is not a problem for system logic.

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