Switch scanning means for use with integrated circuits

• US 4,277,784 A
• Filed: 07/13/1979
• Issued: 07/07/1981
• Est. Priority Date: 07/13/1979
• Status: Expired due to Term

• Current Assignee: AD Technologies LLC
• Original Assignee: Commodore Electronics Limited. (Torque Lifestyle Brands, Inc.)
• Inventors: Hyltin, Tom M.
• Primary Examiner(s): TRAFTON, DAVID
• Application Number:
  US06/057,166
• Time in Patent Office: 725 Days
• Field of Search: 340/711, 340/708, 340/802, 340/765, 236/47, 200/16 R
• US Class Current: 345/87
• CPC Class Codes: G05D 23/1904 variable in time
• CPC Class Codes: G09G 3/04 for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions
• CPC Class Codes: H03M 11/20 Dynamic coding, i.e. by key scanning H03M11/26 takes precedence

Abstract

Method and apparatus for generating a digital data word representative of the position of a switch element which is selectively engageable with one of a plurality of driver conductors which are utilized for conducting actuating signals from a source to a data display system of the type having a plurality of display elements for visually indicating alphanumeric data. The display elements have visually perceptible and imperceptible data indicating states and are characterized by a lagging response to either the application or interruption of the actuating signal wherein a turn-on or turn-off transition interval elapses during a change from one state to the other with the preexisting state of the display element appearing to an observer to remain unchanged during the transition interval. The actuating signals are periodically applied during a load energizing interval through one or more of the driver conductors and are interrupted during a sampling interval. The load energizing interval is much longer in duration relative to the duration of the sampling interval, with the duration of the sampling interval being substantially less than the duration of the turn-off transition interval. Each driver conductor is sequentially pulsed during the sampling interval with a strobe signal having a pulse component duration which is substantially shorter than the turn-on time of the display elements. A number of repetitive events are counted which occur during the interval commencing with the first application of a strobe pulse to a driver conductor of the array and terminating with the application of a strobe pulse to the driver conductor engaged in electrical contact with the data input conductor through the movable switch element. The number of repetitive events counted during the sampling interval is proportional to the number of strobe pulses applied to the driver conductors during the sampling interval and is therefore representative of the position of the movable switch element.

Claims

1. In combination:

a data display device having liquid crystal display elements each characterized by a turn-on and turn-off transition interval;

a data logic circuit having output nodes for conducting actuating signals to said liquid crystal display elements and having a data input node;

driver conductors connecting said data logic output nodes to said display elements;

a data input conductor connected to said data input node;

a switch assembly including a movable switch element for electrically connecting the data input conductor to one of the driver conductors;

a control circuit coupled to the data logic circuit for applying the actuating signals during a load interval and interrupting the actuating signals during a sampling interval, the load interval being longer than the sampling interval and the sampling interval having a duration which is less than the turn-off time of the liquid crystal display elements; and

,

sampling means coupled to said driver conductors and to said data input conductor for pulsing said driver conductors with an electrical strobe signal having a pulse duration less than the turn-on time of the liquid crystal display elements during said sampling interval and for counting a number of repetitive events occurring during the sampling interval commencing with the first application of a strobe pulse to a driver conductor and terminating with the application of a strobe pulse to the driver conductor engaged in electrical contact with the data input conductor through said movable switch element.

2. The combination as defined in claim 1 wherein said switch assembly comprises a slide switch and said movable switch element comprises a wiper arm which is movable from one of said conductors to another.

3. The combination as defined in claim 1 wherein said switch assembly comprises a keyboard and said movable switch element comprises a touch pad which is movable from a non-contacting position to a position of electrically contacting engagement between one of said driver conductors and one of said return conductors.

4. The combination as defined in claim 1 wherein the repetitive events comprise the strobe pulses.

5. The combination as defined in claim 1, wherein the repetitive events comprise a repetitive pulse signal, said combination including:

means for generating the repetitive pulse signal;

a counter coupled to said repetitive pulse signal generating means for counting the repetitive pulses and producing a plurality of data bits defining a data word representative of its count; and

,

said control circuit including means coupled to said counter for starting the counting of said repetitive pulses in response to the first application of a strobe pulse to a driver conductor and for latching said counter and storing the data word representative of its count in response to the transmission of a strobe pulse through the driver conductor engaged in electrical contact with said data input conductor through said movable switch element.

6. Matrix switch apparatus comprising:

a digital data display device having a plurality of display elements for visually indicating alphanumeric data in response to an actuating signal, said display elements each having visually perceptible and imperceptible data indicating states and being characterized by a lagging response to either the application or interruption of the actuating signal wherein a turn-on or turn-off transition interval elapses during a change from one state to the other with the preexisting state of the display element appearing to an observer to remain unchanged during the transition interval;

a data logic circuit having output nodes for conducting actuating signals and a data input node;

a plurality of driver conductors electrically connecting said data output nodes to the data display elements;

a data input conductor connected to said data input node;

a movable switch element for electrically connecting the data input conductor to one of the driver conductors;

a control circuit coupled to the data logic circuit for applying the actuating signals during a load interval and interrupting the actuating signals during a sampling interval, said load interval being longer in duration relative to the duration of the sampling interval, and the duration of the sample interval being less than the duration of the turn-off transition interval of the display elements;

sampling means coupled to said driver conductors for pulsing each driver conductor during said sampling interval with a strobe signal having a pulse component duration less than the turn-on time of said display elements; and

,

counting means coupled to said sampling means and to said data input conductor for counting a number of repetitive events occurring during the interval commencing with the first application of a strobe pulse to a driver conductor and terminating with the application of a strobe pulse to the driver conductor engaged in electrical contact with the data input conductor through the movable switch element.

7. In a digital data display system of the type having a plurality of display elements for visually indicating alphanumeric data in response to an actuating signal, said display elements each having visually perceptible and imperceptible data indicating states and being characterized by a lagging response to either the application or interruption of the actuating signal wherein a turn-on or turn-off transition interval elapses during a change from one state to the other with the preexisting visual state of the display element appearing to an observer to remain unchanged during the transition interval, a data logic circuit having output nodes for driving said visual display elements and a data input node, and a plurality of driver conductors electrically connecting said data output nodes to said data display elements, the combination with said driver conductors of a data input conductor connected to said data input node, a movable switch element for electrically connecting the data input conductor to one of the driver conductors, a strobe generator electrically coupled to said driver conductors for pulsing each driver conductor with a strobe pulse having a duration which is less than the duration of the turn-on transition interval during a sampling interval having a duration which is less than the duration of the display element turn-off transition interval, a counter coupled to said strobe generator for counting the strobe pulses and producing a plurality of data bits defining a data word representative of its count, and control circuit means coupled to said data logic circuit, data input conductor and counter for interrupting the display actuating signals during said sampling interval and applying said strobe pulses to said driver conductors, starting the counting of the strobe pulses in response to the first application of a strobe pulse to a driver conductor, latching the counter and storing the data word representative of its count in response to the transmission of a strobe pulse through the data input conductor.

8. In apparatus having a plurality of driver conductors disposed in an array for conducting actuating signals to a group of display elements for visually indicating alphanumeric data, wherein each display element is characterized by a turn-on and turn-off transition interval, the combination with the driver conductor array of a plurality of data input conductors disposed for electrical connection with each of the primary conductors;

a plurality of switch assemblies for visually indicating a number of data set points of one or more assigned functions, respectively, over a range with resolution of the function associated with a particular switch assembly within said range corresponding to the number of columns of driver conductors and the numner of assigned functions corresponding to the number of rows of data input conductors, each switch assembly including a movable switch element for electrically connecting a data input conductor to a selected one of the driver conductors, the position of said movable switch element being manually adjustable for one driver conductor to another for establishing a discrete electrical connection between its associated data input conductor and any selected one of the driver conductors, means for applying the actuating signals through the driver conductors during a load interval and interrupting the actuating signals during a sampling interval, wherein said load interval being much longer in duration relative to the duration of the sampling interval, and the duration of the sampling interval being less than the duration of the turn-off transition of the display elements;

sampling means coupled to said driver conductors for pulsing said driver conductors during said sampling interval with a strobe signal having a pulse component duration less than the turn-on transition interval of said display elements; and

for each assigned function, counting means coupled to said sampling means and to said data input conductors for counting a number of repetitive events occurring during the interval commencing with the first application of a strobe pulse to a driver conductor and terminating with the application of a strobe pulse to the driver conductor engaged in electrical contact with the data input conductor through the movable switch element corresponding with

9. In apparatus having a plurality of driver conductors disposed in an array for conducting actuating signals to a group of display elements for visually indicating alphanumeric data, wherein each display element is characterized by a turn-on and turn-off transition interval during which intervals the preexisting data-indicating state appears to remain unchanged, the combination with the driver conductor array of a plurality of data input conductors disposed for electrical contact with each of the primary conductors;

said driver and data input conductors defining a conductor matrix having columns and rows formed by the driver conductors and data input conductors, respectively;

a switch assembly having a movable conductor element electrically coupled between each intersection of the row and column conductors for selectively establishing a momentary electrical contact between the row and column conductors at each matrix intersection;

means for applying the actuating signals through the driver conductors during a load interval and interrupting the actuating signals during a sampling interval, wherein said load interval being longer in duration relative to the duration of the sampling interval, and the duration of the sampling interval being less than the duration to the turn-off transition interval of the display elements;

sampling means coupled to said driver conductors for pulsing each driver conductor during said sampling interval with a strobe signal having a pulse component duration less than the duration of the turn-on transition interval of said display elements; and

for each row of data input conductors, counting means coupled to said sampling means and to said data input conductors for counting a number of repetitive events occurring during the interval commencing with the application of a strobe pulse to the first driver conductor of the matrix and terminating upon the first occurrence of the application of a strobe pulse of the sequence to a driver conductor engaged in electrical contact with the associated data input conductor through one of the movable switch elements in the corresponding row.

10. In electrical apparatus having a plurality of data display elements, a data transmission circuit for generating a plurality of data signals representative of alphanumeric data, and a plurality of driver conductors interconnecting the data transmission circuit with the data display elements, the combination of a control circuit coupled to said data transmission circuit for interrupting the data signals during a scan interval having a duration which is less than the turn-off time of the data display elements, a strobe circuit coupled to said driver conductors for pulsing the driver conductors with an electrical strobe signal having a pulse duration less than the turn-on time of the data display elements, and a counting circuit coupled to said strobe circuit and to a selected one of the driver conductors for counting the number of strobe pulses applied during the scan interval commencing with the first application of a strobe pulse to a driver conductor and terminating with the application of a strobe pulse to said selected driver conductor.

11. A method for generating a digital data word representative of the position of a movable switch element which is selectively engageable in discrete contacting relation with one of a plurality of driver conductors which are utilized for conducting actuating signals from a source to a data display system of the type having a plurality of display elements for visually indicating alphanumeric data, each display element having visually perceptible and imperceptible data indicating states and being characterized by a lagging response to either the application or interruption of the actuating signal wherein a turn-on or turn-off transition interval elapses during a change from one state to the other with the preexisting state of the display element appearing to an observer to remain unchanged during the transition interval, said method comprising the steps:

applying the load actuating signals from said source to the display elements of the data display system through one or more of said driver conductors during a load energizing interval and interrupting the load actuating signals during a sampling interval, said load energizing interval being much longer in duration relative to the duration of the sampling interval, and the duration of the sampling interval being less than the duration of the turn-off transition interval of the display elements;

pulsing said driver conductors during said sampling interval with a strobe signal having a pulse component duration less than the turn-on time of said display elements;

counting a number of repetitive events occuring during the interval commencing with the first application of a strobe pulse to a driver conductor and terminating with the application of a strobe pulse to the driver conductor engaged in electrical contact with the data input conductor through the movable switch element; and

,

producing a plurality of data bits representative of the number of repetitive events counted during said sampling interval.

12. The method as defined in claim 11, including the step of establishing each conductor at a common potential level prior to applying said strobe pulses and wherein each driver conductor is sequentially pulsed from said common potential level to a different potential level.

13. A method for generating a digital data word representative of the row and column location of a switch element in a switch matrix having conductor elements coupled between the intersections of row and column conductors for selectively establishing a momentary electrical contact between the row and column conductors at each matrix intersection wherein said column conductors are also utilized for conducting actuating signals from a source to a data display system of the type having a plurality of display elements for visually indicating alphanumeric data, said display elements being characterized by a lagging response to either the application or interruption of the actuating signal wherein a turn-on or turn-off transition interval elapses during a change from one state to the other with the preexisting visual state continuing during the transition interval, said method comprising the steps:

applying the actuating signals through the driver conductors during a load interval and interrupting the actuating signals during a sampling interval, said load interval being longer in duration relative to the duration of the sampling interval, and the duration of the sampling interval being less than the duration of the turn-off transition interval of the display elements;

pulsing each driver conductor during said sampling interval with a strobe signal having a pulse component duration less than the duration of the turn-on transition interval of said display elements;

for each row of data input conductors, counting a number of repetitive events occurring during the interval commencing with the application of a strobe pulse to the first driver conductor of the matrix and terminating upon the first occurrence of the application of a strobe pulse of the sequence to a driver conductor engaged in electrical contact with the associated data input conductor through one of the movable switch elements in the corresponding row; and

,

producing a plurality of data bits representative of the number of repetitive events counted during the sampling interval for each row.