JPH03192930A - Information processor - Google Patents

Abstract

PURPOSE:To prevent missing of a data by informing generation of an error to a sender side when a reception error takes place at the time of transferring data in the serial data transfer of 2-wire type start-stop synchronism type, and allowing the sender side receiving the information to transfer the data having an error again. CONSTITUTION:The processor consists of a switching means 1, a data retransfer command means 2 and a data retransfer means 3. When an error takes place during the transfer of a serial data, the switching means 1 switches a reception enable signal into a reception disable signal, the data retransfer command means 2 issues the retransmission command of a serial data to the sender side equipment and the sender side equipment receives the command and transfers the serial data again to the receiver side. Thus, missing of data at serial data transfer is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an information processing device that performs two-wire asynchronous serial data transfer.

(B) Conventional technology Conventionally, as a signal for data transfer in this type of information processing device, the serial data output T output by the transmitting device is
xD, and a transmission permission output RR output by the receiving device. As shown in Figure 7, the format of serial data is a synchronous format in which a start bit and a stop bit are placed before and after the 8-bit data, respectively, and the start bit is always "0". , and the stop bit is always "1". FIG. 8 is a diagram illustrating conventional transfer processing. In the figure, the receiving side sets RR to "High" if it is in a state where it can receive data, and sets RR to "Low" if it is a reception permission signal. The RR is set to "Low" for processing. On the other hand, when transmitting, the transmitting side refers to the RR and checks whether it is possible to transmit. If the RR is "High", it is possible to transmit. The serial data is output to the receiving side.The transfer process is as follows.In other words, as the processing on the sending side, O
If RR is "High" at the time marked, serial data is output. As shown by ΔA, as a process on the receiving side, RR is set to “Low” during reception to prevent data from being sent continuously.
”.As shown by ΔB, as a process on the receiving side, when reception is completed and the next data can be received, R
Set R to “High”.

(c) Problems to be solved by the invention However, in the two-wire asynchronous serial data transfer described above, if a transmission error is detected on the receiving side, it is not possible to notify the transmitting side that an error has occurred. . Therefore, in data transfer in a conventional information processing apparatus, data in which a reception error has occurred becomes invalid, resulting in so-called data dropout. Types of reception errors include framing errors where the serial data format is not as specified, data errors where the received data is not the specified data, and sampling results that do not match if each bit of the serial data is sampled more than once. There may be a sampling error or something like that.

The present invention has been made in consideration of the above circumstances, and provides an information processing device that can prevent data from being dropped during serial data transfer.

(iv) Means for Solving Problems FIG. 1 is a block diagram showing the basic configuration of the present invention. In the figure, the present invention is configured to connect a transmitting side device and a receiving side device with two signal lines consisting of a data transfer line and a control signal transfer line, and to transfer serial data in an asynchronous format. In an information processing device, a switching means 1 for detecting a serial data transfer error and switching a reception permission signal on a control signal line to a reception disable signal, and a switching means! data retransfer instructing means 2 which gives a serial data retransfer instruction to the transmitting device when the signal is switched to a reception-disabled signal; and data retransfer means 3 which receives the data retransfer instruction and transfers the serial data again.
An information processing device comprising:

The information processing device in this invention may be any device that has at least a transmitting device and a receiving device, and the transmitting device preferably includes a keyboard, and the receiving device specifically includes a keyboard. Specifically, it is preferable that the computer be configured with an office computer main body, a word processor main body, etc. Further, the main body of the receiving device may further be connected to an output device such as a display device or a printing device.

(E) Effect According to the present invention, when an error occurs in the transfer of serial data, the switching means switches the reception permission signal to the reception disable signal, and the data retransmission instruction means instructs the transmitting device to retransmit the serial data. In response to this, the transmitting side device acts to transfer the serial data to the receiving side again.

(F) EXAMPLES The present invention will be described in detail below based on examples shown in the figures. Note that this invention is not limited by this.

FIG. 2 is a block diagram showing the configuration of an information processing device that is an embodiment of the present invention. In the figure, 4 is a keyboard as a transmitting side device, 5 is an information processing device main body (hereinafter referred to as the main body) as a receiving side device, and both are connected to a data transfer line (TxD) 6 and a control signal transfer line (RR).
Connected by two signal lines consisting of 7, the keyboard 4
The serial data input from the main unit 5 is transferred to the main body 5 in an asynchronous format.

A microcomputer built into the main body 5 controls the output of the control line RR. That is, when a serial data transfer error is detected, the reception permission signal on the control signal line RR is changed to a reception disable signal, and when the reception permission signal is switched to the reception disable signal, control is performed to issue a serial data retransfer instruction to the keyboard 4.

Further, the keyboard 4 receives a data retransfer instruction from the main body 5 and transfers the serial data again.

3 and 4 are diagrams for explaining the data transfer process of the information processing apparatus, with FIG. 3 showing the data transfer process during normal operation, and FIG. 4 showing the data transfer process when a reception error occurs.

In Fig. 3, in normal case, the keyboard 4 side is R
If R is High (O mark A), the serial data is transferred to the main body 5, and once the main body 5 starts receiving, it keeps RR "Low" until the reception is completed.

Then, the keyboard 4 side refers to RR before the stop bit output ends, and if it is "Low", it determines that the transfer has ended normally and ends the transfer.

In Fig. 4, when a reception error occurs, when the reception error is detected, the RR is set to “H” by the end of the stop bit.
(ΔC) to notify the keyboard 4 of the error.The keyboard 4 side presses R before the stop bit output ends.
Determine that there is a transfer error by referring to R (
○ mark C). If a transfer error is determined, the keyboard 4 side transfers the serial data again. Then, before the stop bit output ends, refer to the RR (O mark B), and if it is "Low", it is determined that the transfer has ended normally, and the transfer is ended.

FIG. 5 is a flowchart showing the processing on the main body 5 side of this embodiment, and FIG. 6 is a flowchart showing the processing on the keyboard 4 side.

In Fig. 5, first, if reception is possible, set RR to High.
Next, step to-11), and if reception is not possible, set RR to "Low" (step IO→12).

When data reception starts after step 11 (step 13), RR is set to "Low" (step 14).
), then it is determined whether there is a reception error (step 15). If there is no reception error, it is then determined in step 16) whether reception has ended, and when reception is completed, the received data is processed (step 17) and the process returns to step 10. If it is determined that a reception error has occurred in step 15, the RR is set to "High" to notify the keyboard 4 of the reception error (step 18).
At the same time, the process returns to step 13.

In FIG. 6, it is determined whether there is transmission data or not (Step 20), and if YES, it is determined whether RR is "High" or not (Step 21).
gh", output serial data. Step 22
), then RR goes “Low” before the stop bit output ends.
”, that is, check whether a reception error has occurred (step 23); if YES, return to step 20.
In other words, if a reception error has occurred, step 21
Return to , and resend the serial data.

(G) Effects of the Invention According to the present invention, in two-wire asynchronous serial data transfer, if a reception error occurs during data transfer, the transmitting side is notified that an error has occurred, and the transmitter receives the notification. Since the sending side retransmits the data in which the error occurred, it is possible to prevent data from being omitted.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of this invention, FIG. 2 is a block diagram showing the configuration of an embodiment of this invention, and FIGS. 3 and 4 are diagrams for explaining the data transfer process of the embodiment. FIGS. 5 and 6 are flowcharts for explaining the operation of the embodiment, and FIGS. 7 and 8 are explanatory diagrams for explaining the data transfer process of the conventional example. l...Switching means, 2...Data retransfer instruction means, 3...
Data retransmission means. Figure 1 Timing 7 at 4-dollar mark Figure Serial data format

Claims (1)

[Claims] 1. The transmitting side device and the receiving side device are connected by two signal lines consisting of a data transfer line and a control signal transfer line, and configured to transfer serial data in a start-stop synchronization format. In the information processing device, the switching means detects a serial data transfer error and switches a reception permission signal on a control signal line to a reception disable signal;
data retransfer instruction means for giving a serial data retransfer instruction to the transmitting device when the switching means switches to a reception-disabled signal; and data retransfer means for receiving the data retransfer instruction and transmitting the serial data again. An information processing device comprising: