Data communication method between circuits

• US 5,467,200 A
• Filed: 11/04/1993
• Issued: 11/14/1995
• Est. Priority Date: 08/17/1989
• Status: Expired due to Fees

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Ohsawa, Yutaka, Hashimoto, Isamu
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): Grant, II, Jerome
• Application Number:
  US08/145,947
• Time in Patent Office: 740 Days
• Field of Search: 358/426, 358/468, 358/427, 358/261.1, 358/261.2, 358/261.3, 358/262.1, 358/431, 358/432, 359/154, 359/186, 359/185, 455/78, 455/82, 455/88, 455/89, 371/30, 371/32, 370/26, 370/8, 370/9
• US Class Current: 398/41
• CPC Class Codes: G08C 19/28 using pulse code

Abstract

A method for performing data communication between two circuits is provided. The method comprises the steps of: serially transmitting information between two circuits, determining a first level change in one direction of a pulse signal output from one of the circuits to the other as a reference time, judging whether a first data bit is "1" or "0" in accordance with a time period from the reference time to a second level change in the one direction following the reference time, and determining the second level change in the one direction as the reference time relative to the next bit of data in the pulse signal, whereby data of a predetermined number of bits are continuously transmitted.

Claims

1. A method for performing data communication between a pair of circuits, the data communication being established by serially transmitting information which is composed of pulse signals, wherein the pair of circuits are connected by a single bi-directional communication line, and wherein the data communication is performed in accordance with a duty modulation system using a format including a first predetermined time period, a second predetermined time period and a third predetermined time period, the first predetermined time period being defined as a time period from a time of detection of an instant of first level change of a signal level which is being output to the communication line to a time of detection of the instant of a second level change of the signal level following the instant of the first level change, the second predetermined time period being defined as a time period capable of giving data of "1" or "0" to the bi-directional communication line within the first predetermined time period, the third predetermined time period being defined as a time period for holding a level of the communication line following the second predetermined time period at "0" or "1."

2. A method according to claim 1, wherein the first level change and the second level change are increases in the signal level.

3. A method according to claim 1, wherein the first level change and the second level change are decreases in the signal level.

4. A method according to claim 1, wherein the first level change and the second level change are one of increases or decreases in the signal level.

5. A method for performing data communication between a pair of circuits, the data communication being established by serially transmitting information which is composed of pulse signals, wherein the pair of circuits are connected by a single communication line, and wherein the data communication is performed in accordance with a bit level time position fixing using a format in which a reference time is assigned at a time point at which the instant of a first level change of a signal level, being output to the communication line, occurs;

second and onward level changes each being output at integral multiples of a first predetermined time after the reference time when the signal is outputting "0" data bits and said second and onward level changes each being output at integral multiples of a second predetermined time, different from the first predetermined time, when the signal is outputting "1" data bits.

6. A method according to claim 5, wherein the first level change and the second level change are increases in the signal level.

7. A method according to claim 5, wherein the first level change and the second level change are decreases in the signal level.

8. A method according to claim 5, wherein the first level change and the second level change are one of increases or decreases in the signal level.

9. A method for performing a bi-directional data communication between a pair of circuits, the data communication being established by serially transmitting information which is composed of pulse signals, wherein each of the circuits include a light emitting element for emitting infrared light, a light receiving element for receiving infrared light, a control circuit for controlling the light emitting element, and a processing circuit for processing signals received in the light receiving element, and wherein the bi-directional data communication is performed in accordance with a duty modulation using a format including a first predetermined time period, a second predetermined time period and a third predetermined time period, the first predetermined time period being defined as a time period from a time of detection of a first level change of infrared light to be output to a time of detection of a subsequent second level change, following the first level change, the second predetermined time period being defined as a time period capable of giving data of "1" or "0" to the infrared light within the first predetermined time period, the third predetermined time period being defined as a time period for holding a level of the infrared light following the second predetermined time period at "0" or "1."

10. A method according to claim 9, wherein the first level change of infrared light and the second level change of infrared light occur when the infrared light changes states between "OFF" and "ON".

11. A method for performing data communication between a pair of circuits, the data communication being established by serially transmitting information which is composed of pulse signals, wherein each of the circuits include a light emitting element for emitting infrared light, a light receiving element for receiving infrared light, a control circuit for controlling the light emitting element, and a processing circuit for processing signals received in the light receiving element, and wherein the data communication is performed by means of a pulse width modulation in which a time period from a first level change of the infrared light to be output to a second level change of the infrared light is modified in accordance with whether "0" or "1" data bits are output.

12. A method according to claim 11, wherein the first level change of infrared light and the second level change of infrared light occur when the infrared light changes states between "OFF" and "ON".

15. The method of claim 11, wherein the step of serially transmitting information comprises transmitting serial information using a bi-directional communication line.

13. A method for performing data communication between a pair of circuits, the data communication being established by serially transmitting information composed of pulse signals, wherein each of the circuits includes a light emitting element for emitting infrared light, a light receiving element for receiving infrared light, a control circuit for controlling the light emitting element, and a processing circuit for processing signals received in the light receiving element, and wherein the data communication is performed in accordance with a bit level time position fixing using a format in which a time point at which a first level change of an infrared light occurs is assigned as a reference time, and second and onward level changes are each output at integral multiples of a first predetermined time from the reference time when outputting "0" data bits, whereas second and onward level changes are each output at integral multiples of a second predetermined time different from the first predetermined time when outputting "1" data bits.

14. A method according to claim 13, wherein the first level change of infrared light, and the second and onward level changes of infrared light occur when the infrared light changes states between "OFF" and "ON".