JPH11177637A - Data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the current consumption of a light emitting element when transmitting data. SOLUTION: When the number of bits in data '0' is more than that of data '1', a communication control part 1 switches a selector circuit 4 to the side of B so as to select the output of a bit inverter circuit 2. A transmission data format generating circuit 12 inverts bits while adding a code showing the execution of bit inversion to a bit inversion flag. By performing the bit inversion, the number of bits in data for driving a light emitting element 6 is reduced less than 1/2 without fail. Thus, currents to be consumed by the light emitting element 6 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication apparatus for performing data communication using, for example, light.

[0002]

2. Description of the Related Art There are various communication systems in a conventional infrared communication apparatus for performing data communication using infrared rays. Among them, a representative communication system is a communication system of the Ir-DA 1.0 standard. This communication type infrared communication device includes an infrared light emitting element that emits infrared light, a driving circuit that drives the infrared light emitting element, an infrared light receiving element that receives infrared light and converts it into an electric signal, and an electric light output from the infrared light receiving element. It has a signal waveform shaping circuit that shapes a signal waveform such as a signal level so that a communication control circuit that controls communication for a signal can cope with the signal, and a communication control circuit that controls data communication for transmission and reception.

When an infrared communication device transmits data, a communication control circuit adds a bit necessary for communication, a start bit and a stop bit to the transmission data every eight bits, and adds a flag necessary for communication to the frame. Generate a configuration and transmit it in frame units. In the Ir-DA 1.0 standard system, a frame is formed and when the data is "0" as shown in FIG.
Emit infrared radiation for 16 periods. Accordingly, the communication control circuit generates a pulse signal for actually driving the infrared light emitting element based on the generated transmission data, and outputs the pulse signal to the infrared light emitting element driving circuit. The infrared light emitting element driving circuit drives the infrared light emitting element using the signal.

When data is received, infrared rays radiated from the other party's infrared communication device are received by an infrared light receiving element and converted into electric signals. Since the converted electric signal level is minute, the signal waveform shaping circuit converts the electric signal level into a signal level that can be input by a communication control circuit at a subsequent stage, and outputs the signal level to the communication control circuit. The communication control circuit analyzes the input signal and controls communication and receives data.

[0005]

SUMMARY OF THE INVENTION In an optical communication device,
When data transmission is performed, the light emitting element is driven to emit light, but at this time, a large current is consumed. In a conventional optical communication device, light is radiated based on transmission data. Therefore, in a communication method in which light is radiated when data is “0”, when data having transmission data biased to “0” is transmitted, the ratio of radiating light is reduced. There is a problem that the current consumption increases and the current consumption of the optical communication device increases.

The optical communication device is often used for small portable equipment driven by a battery or the like, since a cable connection is not required for communication. In this case, there is a problem that the operation time of the battery-powered portable device is shortened when the current consumption increases.

It is an object of the present invention to provide a data communication device which solves the above problems.

[0008]

According to a first aspect of the present invention, there is provided a data communication apparatus for performing data communication using light, comprising: Counting means for counting at least one of the number of bits of data that does not emit light, inverting means for inverting the bit of the transmission data according to the count result of the counting means, and whether or not the bit of the transmission data has been inverted by the inversion means Means for inserting command data indicating the following into transmission data.

According to a second aspect of the present invention, in the first aspect, detecting means for detecting command data indicating whether a bit of the received data inserted in the received data is inverted, and wherein the detecting means detects the command data Means for inverting the bit of the received data when detecting is detected.

Further, according to the present invention, in the first aspect, it is determined whether or not it is possible to transmit the bit-inverted data of the transmission data before starting communication with the communication apparatus of the other party. It is characterized by further comprising means for confirming with the communication device.

Further, the invention according to claim 4 is characterized in that, in claim 1, the light is infrared light.

Further, according to a fifth aspect of the present invention, in the data communication apparatus, an inverting means for inverting bits of transmission data to be transmitted, transmission data in which bits from the inversion means are inverted, and transmission data in which bits are not inverted. And means for selecting and transmitting any one of the above.

According to a sixth aspect of the present invention, in the fifth aspect, a judging means for judging whether or not the bit of the received data is inverted, and wherein the bit of the received data is inverted by the judging means. Means for inverting the bit of the received data when the judgment is made.

According to a seventh aspect of the present invention, in the fifth aspect, the transmission data is transmitted depending on whether or not to drive an element in bit units.
When transmitting the bits included in the transmission data, if the number of times of driving the element exceeds a predetermined value, the bits of the transmission data are inverted.

Further, the invention of claim 8 is characterized in that, in claim 7, the element is a light emitting element.

In a ninth aspect of the present invention, in the ninth aspect, the light emitting element is an infrared light emitting element.

In a tenth aspect of the present invention, in the fifth aspect, the transmitting means transmits data indicating whether a bit of the transmission data has been inverted.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described.

FIG. 1 is a functional block diagram of a communication section of an optical communication apparatus to which the present invention is applied. FIG. 2 shows a frame structure of data used by the optical communication apparatus to which the present invention is applied for communication. FIG. 3 shows a format in a byte unit which forms a frame of data.

In FIG. 1, 1 is a communication control unit for controlling transmission and reception of communication, 2 is a bit inversion circuit for inverting the bit of transmission data, and 3 is the number of bits of data for emitting infrared light in the transmission data. A counting circuit for counting, a selector circuit for switching between normal transmission data and bit-inverted transmission data, an infrared light emitting element driving circuit, an infrared light emitting element for emitting infrared light, and an infrared light emitted from a communication device on the other end. Infrared light receiving element to receive light,
8 is a waveform shaping circuit for shaping the waveform of an electric signal output from the infrared light receiving element to generate received data, 9 is a bit inverting circuit for inverting bits of the received data, and 10 is a bit inverting of data added to the received data. A bit inversion flag detection circuit for detecting a bit inversion flag indicating that the operation has been performed, a selector circuit 11 for switching between the normal reception data and the bit-inverted reception data, and a reference numeral 12 for adding a start bit, a stop bit and each flag to the transmission data. A transmission data format generation circuit 13 for generating a frame format of the transmission data converts a pulse signal from the waveform shaping circuit 8 into a data signal and converts the data signal from a start bit, a stop bit in the reception data, and a flag constituting a frame. 14 is a frame separation circuit that separates From the transmission data generated in the configuration of a pulse generating circuit for generating a driving pulse for driving the infrared light emitting element.

In FIG. 2, 21 is a start flag indicating the start of frame data, 22 is a bit inversion flag indicating the presence or absence of bit inversion of transmission data, 23 is a data field, and 24 is an error for checking whether or not a communication error has occurred. The detection field 25 is a stop flag indicating the end of the frame data.

In FIG. 3, reference numeral 31 denotes a start bit;
Is data, and 33 is a stop bit. As shown in FIG. 3, a start bit and a stop bit are added to data constituting a frame in units of one byte.

Next, the operation will be described.

When transmitting data to the communication device of the other party,
The communication control unit 1 outputs transmission data to be transmitted in one transmission operation to the counting circuit 3. In the present embodiment, assuming that infrared rays are radiated when the data is “0”, the counting circuit 3 counts the number of bits of the data “0” in the transmission data and returns the result to the communication control unit 1. The communication control unit 1 compares the previously recognized bit number of the transmission data with the bit number of the data “0” obtained from the counter circuit 3,
The number of bits of data “1” is calculated. When the number of bits of data “0” is smaller than the number of bits of data “1”, the selector circuit 4 is switched to the A side so that normal transmission data is output. Transmission data format generation circuit 12
Adds a start bit and a stop bit to the transmission data in units of bytes so that the data input from the selector circuit 4 has the format shown in FIGS. , An error detection field, and a stop flag. The bit inversion flag added at this time is a code in which bit inversion of data is not performed. The pulse generation circuit 14 converts the generated frame data “0” into a pulse width for actually driving the infrared light emitting element and outputs the pulse width to the infrared light emitting element driving circuit 5. The infrared light emitting element driving circuit 5 drives the infrared light emitting element 6 based on the signal to emit infrared light.

According to the result obtained from the counter circuit 3, when the number of bits of the data "0" is larger than that of the data "1",
The communication control unit 1 switches the selector circuit 4 to the B side so that the output of the bit inversion circuit 2 is selected. The transmission data format generation circuit 12 adds a code indicating that the bit has been inverted to the bit inversion flag, and transmits the same as in the case where the bit inversion is not performed.

When data is received from the other party's communication device, the infrared radiation emitted from the other party's communication device is converted into an electric signal by the infrared light receiving element 7, the waveform is shaped by the waveform shaping circuit 8, and output to the flag separating circuit 13. I do. The flag separating circuit 13 separates the data portion from the flags constituting the frame, and outputs the separated bit inversion flag to the bit inversion flag detection circuit 10. Bit inversion flag detection circuit 10
Monitors the bit inversion flag and sets the selector circuit 11 to the A side so that normal data is selected for a code in which bit inversion of data is not performed. When the bit inversion flag indicates that bit inversion of data is performed, the selector circuit 11 is set to the B side so that the output of the bit inversion circuit 9 is selected.

The data content of the output data of the selector circuit 11 is analyzed by the communication control unit 1. The above operation is performed for each frame to transmit and receive data.

Further, in order to perform the communication of the above embodiment, it is preferable that the other party's communication device also has the same function. Therefore, when starting communication, it is also possible to perform communication for confirming the function of the partner communication device as to whether or not the partner communication device has the function of the present invention, using normal data without first performing bit inversion of data. As a result, when the other communication device also has the function of the present invention, the communication operation of the present invention can be performed for both transmission and reception.

[0029]

As described above, according to the present invention,
When transmitting data, the number of bits of data to be transmitted (for example, data for driving a light emitting element) is counted, and when the number of bits is equal to or more than の of the total number of data, bit inversion is performed on the data. The number of bits of data (for example, data for driving a light emitting element) is always 以下 or less.
As a result, it is possible to reduce a current consumed by a unit (for example, a light emitting element) for outputting data to be transmitted, and to reduce power consumption of the entire communication device.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an optical communication device to which the present invention has been applied.

FIG. 2 is a diagram illustrating a frame configuration of data used by an optical communication apparatus to which the present invention is applied for communication.

FIG. 3 is a diagram showing a format in units of bytes constituting a data frame.

FIG. 4 is a diagram illustrating a relationship between transmission data and a light emitting element drive signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication control part 2, 9-bit inversion circuit 3 Count circuit 4, 11 Selector circuit 5 Infrared light emitting element drive circuit 6 Infrared light emitting element 7 Infrared light receiving element 8 Waveform shaping circuit 12 Format generation circuit 13 Frame separation circuit 14 Pulse generation circuit

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H04B 10/04 10/06 H04L 25/02 303

Claims (10)

[Claims] 1. A data communication device for performing data communication using light, wherein a counting means for counting at least one of a bit number of data for emitting light and a bit number of data for not emitting light in transmission data; Inverting means for inverting the bit of the transmission data in accordance with the count result of the counting means, and means for inserting command data indicating whether or not the bit of the transmission data has been inverted by the inversion means into the transmission data, Data communication device. 2. A detecting means according to claim 1, wherein said detecting means detects command data indicating whether or not the bit of the received data inserted in the received data is inverted. Means for inverting a bit of the received data. 3. The method according to claim 1, wherein whether or not it is possible to transmit data obtained by performing bit inversion of transmission data before starting communication with the communication apparatus on the other end is performed.
A data communication device, further comprising means for confirming with the other communication device. 4. The data communication device according to claim 1, wherein the light is infrared light. 5. In a data communication apparatus, an inverting means for inverting bits of transmission data to be transmitted, and one of transmission data in which the bits from the inversion means are inverted and transmission data in which the bits are not inverted are selected. And a means for transmitting the data. 6. The determining means according to claim 5, wherein said determining means determines whether or not the bit of the received data is inverted, and said determining means determines whether the bit of the received data is inverted. Means for inverting the bit of the received data. 7. The transmission data according to claim 5, wherein the transmission data is transmitted depending on whether or not to drive an element in a bit unit, and the inverting means transmits the bit included in the transmission data when transmitting the bit. A data communication device for inverting bits of transmission data when the number of times of driving an element exceeds a predetermined value. 8. The data communication device according to claim 7, wherein the element is a light emitting element. 9. The data communication device according to claim 8, wherein the light emitting element is an infrared light emitting element. 10. The data communication apparatus according to claim 5, wherein said transmission means transmits data indicating whether or not bits of transmission data have been inverted.