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Mechanical Encoder Mouse Bounce Canceller

IP.com Disclosure Number: IPCOM000034689D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Amagami, A: AUTHOR

Abstract

This article describes a method for cancelling mechanical bouncing noise which a mechanical encoder mouse has intrinsically. This circuit is composed by a logic circuit and can completely eliminate the bouncing noise. It is also simple and very low cost. Two selectors and a 2-bit binary counter are utilized to control two mouse interface signals. A change of the interface signal transfers the state of logic which results in ignoring the following change of watching the line so that it can be free from consecutive counting noise. Fig. 1 shows a timing relationship between two mouse output signals (A and B). The mouse interface logic counts mouse moving distance by counting changing number of signals A, B according to the moving direction which is determined by the phase deference among the signals. (Image Omitted) Fig.

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Mechanical Encoder Mouse Bounce Canceller

This article describes a method for cancelling mechanical bouncing noise which a mechanical encoder mouse has intrinsically. This circuit is composed by a logic circuit and can completely eliminate the bouncing noise. It is also simple and very low cost. Two selectors and a 2-bit binary counter are utilized to control two mouse interface signals. A change of the interface signal transfers the state of logic which results in ignoring the following change of watching the line so that it can be free from consecutive counting noise. Fig. 1 shows a timing relationship between two mouse output signals (A and B). The mouse interface logic counts mouse moving distance by counting changing number of signals A, B according to the moving direction which is determined by the phase deference among the signals.

(Image Omitted)

Fig. 2 shows the detail of signals A, B including bouncing noise. At the first rising edge of signal A, the mouse interface counts up its motion counter. In this situation, a rising edge of A is to be used as a clock input of the counter and B is to be used as the up/down control signal of the counter. During moving mouse, clock source and direction source should be changed as shown in the table of Fig. 3. At the same time, the bouncing noise after the first rising edge of the signal should be canceled. Fig. 3 also shows a basic block diagram of the bounce canceller. This circuit selects clock and direction sourc...