JPH0531410U - Communication device - Google Patents

Abstract

(57) [Summary] [Purpose] The transmission data can be transmitted to the end without the user's awareness with a simple configuration. A communication device comprising a two-stage transmission buffer, a communication driver for transmitting serial data to a communication medium, and a communication control circuit for performing communication control for continuously transmitting serial data, the communication device comprising: Input a transmission complete signal from the second stage transmission buffer connected to the driver,
A communication driver control means for inputting a transmission end instruction signal from the communication control circuit and for instructing the communication driver to disable transmission based on the both input signals is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a communication device that performs clock-synchronous serial communication, and more specifically, enables data to be output to the end without leaving unoutput data in the transmission buffer when the transmission operation is stopped. Regarding communication equipment.

[0002]

[Prior Art]

 FIG. 6 is a schematic diagram of the configuration of a communication device having a conventional clock-synchronous serial communication function. In this device, two-stage transmission data buffers 2 and 3 are connected to the output side of the communication control circuit 1, and the transmission data from the communication control circuit 1 passes through the two transmission data buffers 2 and 3 and the communication driver 4 With this, serial data can be continuously transmitted to a communication medium (not shown). That is, the communication control circuit 1 first writes data in the transmission buffer 2 in the first stage. Then, the data is transferred to the transmission buffer 3 in the second stage. As a result, the first-stage transmission buffer 1 becomes empty, so that the communication control circuit 1 is notified of this via the transmission completion notification line 5 and a request is made to write the next transmission data. There is.

[0003]

[Problems to be solved by the device]

 However, after writing the final data to the transmission buffer 2 in the first stage, when the completion of transmission is notified and the communication stop is instructed via the communication enable line 6, a part of the final transmission data is not transmitted and the second stage is not transmitted. There is a problem that the eye remains in the transmission buffer 3.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a serial communication device capable of reliably transmitting data up to the last data.

[0005]

[Means for Solving the Problems]

 The present invention, which solves such a problem, has a two-stage transmission buffer, a communication driver for sending serial data from the two-stage transmission buffer to a communication medium, and serial data synchronized from this communication driver to a clock. And a communication control circuit for performing communication control for continuously transmitting data, wherein a transmission completion signal is input from a second-stage transmission buffer connected to the communication driver, and the communication control circuit A communication device is provided with communication driver control means for inputting a transmission end instruction signal and for instructing the communication driver to disable transmission based on both input signals.

[0006]

[Action]

 The communication driver control means does not end the communication operation with respect to the communication driver only by the communication end command from the communication control circuit, until the transmission completion notification of the second stage transmission buffer is output. Instruct the communication driver to continue the transmission operation.

This prevents the transmission operation from ending with the data to be transmitted remaining in the second-stage transmission buffer.

[0008]

【Example】

 Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration block diagram showing an embodiment of the present invention. In the figure, the same parts as those of the conventional apparatus of FIG. 6 are designated by the same reference numerals. In this embodiment, 2 and 3 are transmission buffers connected in two stages, 4 is a communication driver for sending the data from the transmission buffer 3 in the second stage to a communication medium, 1 is a communication control circuit, and 1st stage It is configured to receive a transmission completion notification signal from the second transmission buffer 2 and write the next data to the first-stage transmission buffer, whereby serial data synchronized with the clock from the communication driver 4 is transferred. The communication is controlled so that it is continuously transmitted to the communication medium.

Reference numeral 7 is a control means of the communication driver 4, which is a feature of the present invention, and inputs a transmission completion signal from the second-stage transmission buffer 3 connected to the communication driver 4 via the notification line 8 and performs communication. A transmission end instruction signal is input from the control circuit 1 via the instruction line 6, and the communication driver 4 is instructed to disable transmission based on both input signals.

The operation of the apparatus thus configured will be described below. FIG. 2 is a flowchart showing the communication control operation performed by the communication control circuit 1. First, the communication driver 4 is instructed to the enabled state via the communication driver control means 7. In this state, the data is written in the first stage transmission buffer 2 until the final data is reached, and the data written in the transmission buffer 2 is transferred. When the transfer is completed, the communication driver control means 7 is instructed to disable the transmission of the communication driver 4.

FIG. 3 is a flowchart showing the operation of the first-stage transmission buffer 2. When there is write data from the communication control circuit 1, it is judged whether or not the second-stage transmission buffer 3 is empty. If it is, the written data is sequentially transferred to the second-stage transmission buffer 3, When the transfer is completed, a transfer completion notification is sent to the communication control circuit 1.

FIG. 4 is a flowchart showing the operation of the second-stage transmission buffer 3. When data is transferred from the transmission buffer 2 of the first stage, it is serially transmitted bit by bit toward the communication medium via the communication driver 4. When the transmission is completed for all the bits, a transmission completion notification is sent to the communication driver control means 7.

FIG. 5 is a flowchart showing the operation of the communication driver control means 7. When a transmission enable instruction is given from the communication control circuit 1, a transmission enable signal is output to the communication driver 4. As a result, the serial data from the second-stage transmission buffer 3 can be transmitted to the communication medium side. Next, it is monitored whether there is a disable instruction from the communication control circuit 1, and if there is such an instruction, then it is monitored whether a transmission completion notification comes from the second stage transmission buffer 3. Then, when the transmission completion notification is sent from the second-stage transmission buffer 3, the transmission disable is sent to the communication driver 4, and the communication driver 4 stops the transmission at the time of receiving the notification. That is, even if the communication control circuit 1 gives a disable instruction, the transmission operation is continued until the transmission completion notification of the second stage transmission buffer 3 is output.

By such an operation, the transmission operation does not end with the data to be transmitted remaining in the transmission buffer 3 in the second stage.

[0015]

[Effect of the device]

 As described above in detail, according to the present invention, in the synchronous serial communication device having the two-stage transmission buffer, the transmission completion signal from the second-stage transmission buffer and the transmission disable signal from the communication control circuit are provided. A communication driver control unit that controls the operation of the communication driver according to the signal is provided, and a highly reliable communication device that can transmit the transmission data to the end without realizing the user with a simple configuration is realized. be able to.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a communication control operation performed by a communication control circuit.

FIG. 3 is a flowchart showing an operation of a first stage transmission buffer.

FIG. 4 is a flowchart showing an operation of a second stage transmission buffer.

FIG. 5 is a flowchart showing the operation of the communication driver control means.

FIG. 6 is a configuration conceptual diagram of a communication device having a conventional clock-synchronous serial communication function.

[Explanation of symbols]

 1 Communication Control Circuit 2 First Stage Transmission Buffer 3 Second Stage Transmission Buffer 4 Communication Driver 7 Communication Driver Control Means

Claims (1)

[Scope of utility model registration request] 1. A two-stage transmission buffer, a communication driver for sending serial data from the two-stage transmission buffer to a communication medium, and serial data synchronized with a clock from the communication driver. And a communication control circuit for controlling the communication of the communication device, wherein a transmission completion signal is input from a second-stage transmission buffer connected to the communication driver, and a transmission end instruction signal is input from the communication control circuit. A communication device comprising communication driver control means for instructing the communication driver to disable transmission based on both input signals.