JPH05108508A - Data transmitter - Google Patents

Abstract

PURPOSE:To provide a function for holding data on a communication path until it is confirmed that the data transmitted onto the communication path are normally received without fail. CONSTITUTION:This device is equipped with a transmission buffer 13 to output transmitting data which error can be detected, transmission control part 12 to transmit the transmitting data outputted from the transmission buffer 13 onto communication paths 31 and 32 and to execute control for holding the state of transmitting the data onto the communication paths 31 and 32 until the reception of a signal reporting the complete reception of the said data, parity check part 23 to detect error from the data transmitted from the transmission control part 12 and held on the communication paths and to output an error signal, and reception control part 22 to transmit a signal reporting the complete reception of the data to a communicating means when no error signal is outputted from the parity check part 23 and the data held on the communication paths 31 and 32 are not required any more.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission device having an error detecting function for digital information transmitted in a predetermined bit unit.

[0002]

2. Description of the Related Art In order to realize a highly reliable communication path (data transmission path) for digital signals, it is necessary to detect a data error occurring in a device involved in communication (data transmission),
It is necessary to correct the error. Regarding this type of data error detection and error correction, various data error detection / correction methods have been proposed in the past and applied to many devices. Generally, there are the following two methods for data error detection / correction.

1). A method in which error-detectable data is used for communication to perform only error detection, and when an error is detected, the data is retransmitted to correct the error (eg, parity check method).

2). A method of correcting an error by using error-detectable data for communication and performing an error correction process on the data when an error is detected (eg, ECC (Erro
r Checking and Correction) method).

In general, the latter method described in the above item 2) has a limitation in correction capability. Therefore, when an error is detected but the error cannot be corrected (multi-bit error), the above 1) is used.
It is necessary to retransmit the data in the same manner as the former method described in the section.

As described above, it is generally necessary to retransmit data in order to realize highly reliable communication (data transmission). However, in order to realize the data retransmitting means, it is necessary to add hardware or software, and when an error is detected, it is necessary to redo communication,
Various problems occur, such as an increase in the total communication time.

Particularly, in a system that is easily affected by external noise such as radio interference, the frequency of error occurrence is high, and therefore the overhead of performance of data retransmission on performance is large.

[0008]

As described above, retransmission of data is indispensable for realizing highly reliable communication, but addition of hardware or software is required for retransmission of data. In addition, when an error is detected, it is necessary to re-communicate, which causes various problems such as an increase in the total communication time.

The present invention has been made in view of the above situation,
In a data transmission device using a bus or the like capable of holding data on a communication path (data transmission path) by a communication means, data transmission capable of reducing overhead such as data retransmission and realizing a highly reliable data transmission / reception mechanism The purpose is to provide a device. [Constitution of Invention]

[0010]

The present invention is characterized in that it has a function of holding data on a communication path until it is confirmed that the data sent on the communication path is correctly received without error. And

That is, according to the present invention, data output means for outputting error-detectable transmission data, data output from this data output means are held on a communication path, and the fact that the data on the communication path has been received is notified. Communication means for holding the data on the communication path until an acknowledge signal (ACK) is confirmed, and error detection means for detecting an error from the data held on the communication path by this communication means and outputting an error signal, And a control means for sending an acknowledge signal to the communication means when no error signal is output and the data on the communication path becomes unnecessary.

Further, when the time for which the data is held on the communication path by the communication means becomes a certain time or more,
An error output means for outputting an error signal is provided.

[0013]

According to the present invention, the error-detectable data output by the data output means is held by the communication means, and the data is used by the user. The user does not use the data on the communication path while the data error signal is being output from the error detecting means, and the control means does not output an acknowledge signal (ACK). Further, the user uses the data on the communication path when the communication means has data on the communication path and the error detecting means does not output a data error signal. Further, the control means sends an acknowledge signal indicating that the data on the communication path has been received, to the communication means.

As a result, when there is an error on the communication path, the communication is not completed and the user does not use the erroneous data, so that there is an intermittent failure due to radio wave interference or the characteristics of hardware constituent elements. And a highly reliable data transmission device can be realized.

When a data error occurs due to a steady fault, the control means does not output an acknowledge signal, so that the communication means keeps the data on the communication path. Therefore, the error output means keeps the user steady. You can know the breakdown.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the case where the parity check is used as the error detection has been described as an example, but the present invention is not limited to this and can be realized by other error detecting means. .. FIG. 1 is a block diagram showing a configuration of a main part of a data transmission device according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a transmission unit for transmitting the data output from the data output unit 10 (here, 16-bit parallel data (DATA 0 to 15)).
Is a receiving unit that receives the data output from the data output unit 10 via the transmitting unit 1 and the communication paths (31 to 34) and transfers the data to the data user unit 20.

The data output unit 10 outputs the data (DATA 0 to 15) having a 16-bit structure on the data line 14, and then outputs the control signal 16 indicating that the data is output to the data line 14. The data user unit 20 takes in the data on the data line 24 and uses it when the data available signal 28 is confirmed. Reference numerals 11 to 13 are components of the transmission unit 1, and 11 is a parity generation unit,
Reference numeral 12 is a transmission control unit, and 13 is a transmission buffer.

The parity generator 11 generates a parity bit from the data (DATA 0 to 15) on the data line 14 and outputs it to the data line 17. To generate the parity bit, a method of taking the exclusive OR of all the bits is used.

The transmission control unit 12 outputs the control signal 16 indicating that the data output unit 10 has output the data (DATA 0 to 15) on the data line 14 and then outputs the acknowledge line 3
Output enable signal (O
E) 15 and the strobe line 34 included in the communication line are asserted. In addition, after asserting the strobe signal line 34, the timeout signal 18 is output when the acknowledge line 33 included in the communication line is not asserted within a fixed time.

In the transmission buffer 13, when the output enable signal (OE) 15 is asserted, the data (DATA 0 to 15) on the data line 14 is included in the communication line as the data line 31.
In addition, the value (PARITY) of the data line 17 is output onto the data line 32 included in the communication line. Reference numerals 21 to 23 are constituent elements of the reception unit 2, 21 is a reception register, 22 is a reception control unit, and 23 is a parity check unit.

The reception register 21 has a set signal (SET).
Data line 31 and data line 3 when 25 is output
The value of 2 (DATA 0 to 15 · PARITY) is stored and output to the data line 24 and the data line 27, respectively.

The reception controller 22 outputs a set signal (SET) 25 when the strobe line 34 is asserted. Further, after the set signal (SET) 25 is output, when the output of the error signal (ERR) 26 is confirmed after a fixed time, the set signal (SET) 25 is output again. Further, after the set signal (SET) 25 is output, when the output of the error signal (ERR) 26 is not confirmed after a certain period of time, the acknowledge line 3 until the strobe line 34 is negated.
3 is asserted and the data available signal 28 is output.

The parity check unit 23 has a data line 24.
And the value of the data line 27 (DATA 0 to 15 / PARITY) is used for error detection. When an error is detected, an error signal (ERR
) 26 is output. For error detection, the exclusive OR of all the signals on the data line 24 is calculated, and the value (PA
RITY) method is used.

31 to 34 are data lines and control signal lines included in the communication line, and 31 is a transmission buffer 1
16-bit wide data line for supplying the data (DATA 0 to 15) output via 3 to the receiving register 21.
Reference numeral 2 is a data line for supplying the parity bit signal (PARITY) output via the data line 32 to the reception register 21, and 33 is an acknowledge signal (ACK) output from the reception control unit 22 to the transmission control unit 12. An acknowledge line for supplying 34 is a strobe line for supplying the strobe signal (STRB) output from the transmission controller 12 to the reception controller 22.

FIG. 2 is a time chart showing the signal state of each part for explaining the operation of the embodiment shown in FIG. 1, and FIG. 2 (a) is a strobe signal (STRB) transmitted through the strobe line 34. ), The same figure (b) shows the acknowledge signal (ACK) transmitted through the acknowledge line 33.
(C) shows an output enable signal (OE) 15 sent from the transmission control unit 12 to the transmission buffer 13, and (d) of FIG. 16 is transmitted via the data line 31.
The output timing of the bit data (DATA 0 to 15) is shown, (e) of the figure shows the output timing of the parity bit signal (PARITY) transmitted via the data line 32, and (f) of the figure shows the reception control. The set signal (SET) 25 sent from the unit 22 to the reception register 21 is shown, and the figure (g) shows the error signal (ERR) 26 sent from the parity check unit 23 to the reception control unit 22. Here, FIG. 1 and FIG.
The operation in the embodiment of the present invention will be described with reference to FIG.

The data output unit 10 transmits the transmission data (DATA 0
15 to 15) are output to the data line 14, and the control signal 16 indicating that the data is output to the data line 14 is output.

The transmission data (DATA 0 to 15) output from the data output unit 10 and the control signal 16 are sent to the transmission unit 1 respectively, and the transmission data (DATA 0 to 1) on the data line 14 is sent.
5) is transmitted to the receiving unit 2 under the control according to the control signal 16.

In the transmission unit 1, the transmission data (DATA 0 to 15) output on the data line 14 is supplied to the parity generation unit 11 and also supplied to and stored in the transmission buffer 13. Further, the control signal 16 is transmitted to the transmission control unit 1
2 is supplied.

The parity generator 11 generates a parity bit signal (PARITY) from the transmission data (DATA 0 to 15) received via the data line 14 and outputs it to the data line 17. The parity bit signal (PARITY) on the data line 17 is stored in the transmission buffer 13 together with the corresponding data (DATA 0 to 15).

Upon receiving the control signal 16, the transmission controller 12 outputs the output enable signal (OE) to the transmission buffer 13.
15 is sent (see FIG. 2C) and the strobe line 34 is asserted (see FIG. 2A).

Upon receiving the output enable signal (OE) 15 from the transmission controller 12, the transmission buffer 13 receives the data line 1
Data received via 4 (DATA 0-15) and data line 17
And a parity bit signal (PARITY) received via the data line 31 and the data line 32, respectively (see FIG. 2).
(See (d) and (e)).

The reception control section 22 provided in the reception section 2 is
When it is confirmed that the strobe line 34 is asserted by the transmission controller 12, the set signal (SET) 25 is output to the reception register 21 after a fixed time (FIG. 2 (f)).
reference).

The reception register 21 has a set signal (SET) 2
When 5 is received, the data on the data line 31 (DATA 0 to 15)
And the parity bit signal (PARITY) on the data line 32 are held, the held data (DATA 0 to 15) are held on the data line 24, and the parity bit signal (PARITY) is held on the data line 27.
Output to each.

The parity check unit 23 includes a data line 24.
A parity check is carried out by means of the data line 27 and an error signal (ERR) 26 is output when a data error is confirmed (see FIG. 2 (g)).

The reception control unit 22 uses the set signal (SET) 2
Error signal (ERR) 26 after a fixed time after 5 is output
2), the set signal (SET) 25 is output again to the reception register 21 (see FIG. 2 (f)), and the values (DATA 0 to 15 · PARITY) of the data lines 31 and 32 are
The reception register 21 is set again. This process is repeatedly executed until the parity check unit 23 does not confirm the data error.

Therefore, since the reception register 21 always stores data in which no data error is confirmed (correct data without data error), it is possible to exclude the delivery of errored abnormal data to the data user unit 20, and Line 3
It is possible to protect the data user unit 20 from an intermittent failure due to noise or the like on 1, 32.

The reception control unit 22 includes a parity check unit 2
When no data error is detected by 3, the control signal (data available signal) 28 is output to notify the data user unit 20 that the data (DATA 0 to 15) on the data line 24 can be used. At the same time, the acknowledge line 33 is asserted to notify the transmission control unit 12 that the reception is completed (see FIG. 2B).

Further, a steady failure occurs in the data line 31,
When the acknowledge line 33 is not asserted by the transmission control unit 12 within a fixed time after the strobe line 34 is asserted, the transmission control unit 12 determines that the timeout signal 1
Outputs 8 to notify the outside that a steady failure has occurred.

As described above, since the data is held in the data line 31 until the receiving side confirms that the error-free data is received, the communication of the computer system used in the place where the influence of noise is great. It is possible to supply the data to which the error is not detected to the receiver against the intermittent data error which frequently occurs on the road. Further, by adopting the configuration of the above-described embodiment, the data retransmitting means, which was necessary in the conventional method, is unnecessary, and it can be easily realized by adding a simple control means to the error detecting means, so that it can be implemented under bad conditions. It is effective for use in a communication device that is required to have high reliability.

[0041]

As described above in detail, according to the data transmission apparatus of the present invention, error-detectable transmission data is transmitted on the communication path, and a signal indicating the data transmission state indicating the completion of reception of the data is received. The communication means on the transmitting side that holds up to and the error held in the data sent from the communication means and held on the communication path are checked, and when there is no error and the data held on the communication path becomes unnecessary, By adopting a configuration in which the communication means on the transmission side is provided with a control means for notifying completion of data reception, it is possible to avoid intermittent data error that frequently occurs in a communication path of a computer system used in a place where noise is large. On the other hand, only normal data in which no error is detected can be supplied to the data using device on the receiving side. Further, the above-described configuration of the present invention eliminates the need for the data resending means required in the conventional method, and can be easily realized by adding a simple control means to the error detecting means, so that it can be used under adverse conditions. It is effective when used for a communication device that requires high reliability.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of a data transmission device according to an embodiment of the present invention.

FIG. 2 is a time chart showing signal states of respective parts for explaining the operation of the embodiment shown in FIG.

[Explanation of symbols]

1 ... Transmission unit, 2 ... Reception unit, 10 ... Data output unit, 11 ...
Parity generator, 12 ... Transmission controller, 13 ... Transmission buffer, 14 ... Data line, 15 ... Output enable signal (O
E), 16 ... Control signal, 17 ... Data line, 18 ... Timeout signal, 20 ... Data user section, 21 ... Reception register, 22 ... Reception control section, 23 ... Parity check section, 2
4 ... Data line, 25 ... Set signal (SET), 26 ... Error signal (ERR), 27 ... Data line, 28 ... Data available signal, 31 ... Data line, 32 ... Data line, 33 ... Acknowledge line, 34 ... Strobe line.

Claims (2)

[Claims] 1. A data output means for outputting error-detectable transmission data, a signal for transmitting the transmission data output from the data output means on a communication path, and a signal for notifying the completion of reception of the data in the same data transmission state. Communication means for holding until reception, error detection means for detecting an error from data sent from the communication means and held on the communication path and outputting an error signal, and no error signal output by the error detection means, and A data transmission device comprising: control means for sending a signal notifying completion of data reception to the communication means when the data held on the communication path becomes unnecessary. 2. The data transmission device according to claim 1, further comprising an error output means for outputting an error signal when the data holding time on the communication path exceeds a certain time.