Method which provides debounced inputs from a touch screen panel by waiting until each x and y coordinates stop altering

• US 5,025,411 A
• Filed: 12/08/1986
• Issued: 06/18/1991
• Est. Priority Date: 12/08/1986
• Status: Expired due to Fees

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Sherbeck, Terry G., Tallman, James L.
• Primary Examiner(s): Williams, Jr., Archie E.
• Assistant Examiner(s): Harrell, Robert B.
• Application Number:
  US06/939,645
• Time in Patent Office: 1,653 Days
• Field of Search: 364/300, 364/900 MS File, 364/200 MS File, 340/706, 340/711, 340/712, 340/731, 340/747, 340/702, 340/738, 340/752, 340/762, 340/766
• US Class Current: 345/175
• CPC Class Codes: G01R 13/22 Circuits therefor
• CPC Class Codes: G01R 13/347 using electro-optic elements
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041

Abstract

A system for providing input to a computer comprises a touchscreen apparatus for generating a grid of horizontal and vertical light beams and producing a set of output signals, each indicating whether a corresponding one of the light beams strikes an object. A scanning device repeatedly scans the states of the output signals, stores data representing the last scanned state of each output signal, and transmits a first interrupt signal to the computer whenever the state of any one of the output signals changes. In response to the interrupt signal, the computer reads the stored scan data, determines whether the data indicates that a horizontal and a vertical light beam is striking an object, and if so, sets parameter values to identify the horizontal and vertical light beams. In response to a second interrupt signal periodically generated by a clock, the computer determines whether or not the parameter values have remained constant for a predetermined period, and if so executes a routine responsive to the parameter values.

Claims

1. For an instrument comprising a computer, means for producing a plurality of output signals, and interface means for storing data indicating the states of said output signals, for transmitting and interrupt signal to said computer whenever the state of any one of said output signals changes, and for transferring said data to said computer, a method for said computer for acquiring and responding to said data, the method comprising the steps of:

a. acquiring said data stored by said interface means upon each receipt of said interrupt signal, and setting the value of a first parameter to represent the state of at least one of said plurality of output signals as indicated by said data;

b. concurrently with performing step a, periodically determining whether the value of said first parameter has remained constant for a predetermined period; and

c. initiating a selected action after the first parameter is determined in step b to have remained constant for said predetermined period, said action being selected according to the value of said first parameter.

2. For an oscilloscope comprising a screen, a computer, touchscreen means for transmitting a first plurality of light beams in a first direction across and proximate to the surface of said screen, for transmitting a second plurality of light beams in a second direction across and proximate to the surface of said screen, said first and second directions being nonparallel, and for producing a plurality of output signals, each corresponding to a separate one of said light beams and indicating whether or not the corresponding light beam strikes an object proximate to the surface of said screen, and scanning means for repeatedly scanning states of said plurality of output signals, for storing data indicating the last scanned states of said output signals, and for transmitting an interrupt signal to said computer whenever the state of any one of said output signals changes between scans, a method for said computer for selecting and initiating at least one action, the method comprising the steps of:

a. acquiring said data stored by said scanning means upon each receipt of said interrupt signal and, when the data indicates that a first light beam of said first plurality of light beams and a second light beam of said second plurality of light beams have both struck an object proximate to said screen, setting the value of first parameters to identify said first and second light beams and when the data indicates that no light beams have struck an object, setting the values of said first parameters to predetermined values;

b. concurrently with performing step a, periodically determining whether the values of said first parameters have remained constant for a predetermined period; and

c. selecting and initiating said at least one action when the values of said first parameters are determined in step b to have remained constant for said predetermined period, said at least one action being selected according to the values of said first parameter.