JPH043554A - Interface circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interface circuit for asynchronous serial data communication, particularly to a serial data interface circuit suitable for an interface between aircraft-mounted AVIEX systems.

[Conventional technology]

FIG. 3 shows the configuration of a conventional interface circuit.

In the figure, (1) is a first device that can decide to send and receive data, and (2) is a first device that is capable of receiving data transmitted by (1) and responding with data based on the request. The second device (3) having the first device (1)
and a second device (2), the cable (4a) to (4b) is an asynchronous cable that determines the transmission/reception of data in the first device and the second device. Signal processing section of the equation interface circuit, (5m)
~(5d) converts the data requested by the signal processing unit (4a) of each of the first device (1) and the second device (2) from parallel data to serial data, or converts serial data from the outside into serial data. Serial-to-parallel conversion circuit that converts to parallel data, (6m) ~ (
6b) is a synchronization circuit that generates or reads a synchronization signal; (7
a) to (7b) are the first device (1) and the second device W (2).
) is an isolation transformer for insulating it from ground.

Next, the operation will be explained with reference to the timing chart of FIG. 4 showing the data transmission/reception processing operation.

When transmitting and receiving predetermined data in such a configuration,
Before transferring data, the signal processing unit (4a) of the first device (1) activates the synchronization circuit (6a) as a synchronization signal, and passes the synchronization signal (a) shown in Fig. 4 through the isolation transformer (7a). transferred to the second device (2). Next, the signal processing section (
4a), the predetermined data (a) shown in FIG. 4 is transferred to the serial/parallel converter circuit (5a) and then transferred as serial data to the second device (2) through the isolation transformer (7a). The transferred data (a) is received by the serial/parallel converter gI (5e) through the isolation transformer (7b), and is processed as parallel data by the signal processing section (4b). At this point, the signal processing unit (4b) can grasp the self-recognition code in this parallel data and obtain information on data transmission/reception and the number of transferred words.

Next, if the processed data is a data request required by the first device (1), the signal processing device section (4b) transfers the requested data to the serial/parallel converter (5d). The transferred data is converted into serial data (pieces) shown in FIG. 4 at the serial/parallel converter port i (5d) and sent to the first device (1) through the isolation transformer (7b).

The serial data (1) transferred to the first device (1) is transmitted through the isolation transformer (7a) to the data set between the first device (1) and the second device f (21) as shown in FIG. The data waveform (1) is converted into parallel data by the serial/parallel conversion circuit (5b) according to the read timing (o) of the synchronous cycle # (6a), and is read into the signal processing section (4a).

[Problem H that the invention attempts to solve]

Since the conventional asynchronous interface circuit is configured as described above, data transmission and reception between the first device and the second device involves reading serial data including a self-identification code, data type, and data number. There were issues such as not being able to respond immediately to data requests.

This invention is intended to solve the above problems.
In order to respond within a short time when transmitting and receiving data between devices, the recognition code, data type, number of data, etc. are transmitted and received using DC voltage, making the transmission faster than the conventional serial data transmission and reception. The present invention provides an interface circuit for asynchronous serial data transfer.

[Means to solve the problem]

The interface circuit according to the present invention sets a self-recognition code between devices before receiving predetermined data, converts the value into a DC voltage, and transfers the data to a second device. .

[For production]

In order to receive predetermined serial data in a short time, the interface circuit according to the present invention sets the self-recognition code between each device, the N class of data, and the number of data in advance as a DC voltage, so that the interface circuit receives predetermined serial data in a short time before requesting data. A predetermined voltage is then transferred to each device, and requested data can be sent and received in a short time.

〔Example〕

An embodiment of the present invention will now be described.

In FIG. 1, (1) to (7) are the same as in the prior art described above.

(8) is a recognition code voltage generation circuit in which voltages are set for the recognition code between devices, the type of data, and the number of data, and (9) is a recognition code voltage generator that is set with a voltage for the recognition code between devices, the type of data, and the number of data. This is a self-recognition code judgment circuit that grasps the code.

Next, a description will be given with reference to FIG. 2 showing processing timing waveforms of a serial interface circuit according to the present invention.

In such a configuration, when transmitting and receiving predetermined data, the signal processing section (4a) of the first device (1) uses a recognition code voltage generation circuit (8) to generate a recognition code voltage before transmitting the data. In contrast, the recognition code of the second device, the type of data, and the DC voltage corresponding to the number of data are transferred to the second device (2) through the isolation transformer (7a) as shown in the waveform (A) in FIG. 2. Next, the signal processing section (4a)
converts the predetermined data (a) shown in Figure 2 to a serial-to-parallel conversion circuit (
5a) and the isolation transformer (7a) as serial data.
) to the second device (2). The transferred data (a) is received by the serial/parallel converter circuit (5C) through the isolation transformer (7b).

The parallel data is processed by the signal processing unit (4b).

Next, when receiving data, the signal processing unit (4a) converts the predetermined recognition code, data type, and data number into DC voltage using the recognition code voltage generation circuit (8), and passes the data through the isolation transformer (7a). It is transferred as serial data to the second device (2).

The waveforms of the DC data of the DC voltage transferred to the second device (2) shown in Fig. 2 pass through the isolation transformer (7b), and the recognition code is grasped by the self-recognition code determination circuit (9). If it is the recognition code of the device (2), the data type and number of data are sent to the signal processing unit (4b), and the signal processing unit (4b) converts the specified data type and number of data into serial/parallel data. The data specified to the conversion circuit (5d) is passed through the isolation transformer (7b) to the first device (1).
respond to

Self-recognition determination circuit (9) in response to the first device (1)
) is the waveform shown in Fig. 4 at the first device N using a DC voltage.
Send to (1).

Next, the data (1) to be transferred to the first device (1) is read as parallel data by the serial/parallel conversion circuit (5b) through the isolation transformer (7a) and read into the signal processing unit (4a) at the timing (o). It will be done.

In the above embodiment, an asynchronous serial data interface circuit has been described, but the same effects as in the above embodiment can be achieved in a parallel data interface circuit.

〔Effect of the invention〕

As shown above, in the interface circuit according to the present invention, the data transfer time between devices is shortened by transferring the recognition code, type of data, and number of data between devices using a DC voltage using a recognition code voltage generation circuit. There is an effect that can be transferred to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an interface circuit according to an embodiment of the present invention, FIG. 2 is a data reading timing chart in the interface circuit of the present invention, FIG. 3 is a block diagram of a conventional interface circuit, and FIG. 3 is a reading timing chart of a conventional interface circuit. In the figure, (1) is the first device, and (2) is the second device. (3a) to (3b) are cables, (4a) to (4
b) is a signal processing section. (5a) - (5dl is a serial/parallel conversion circuit, (6a)
- (6b) are synchronous circuits, (7a) - (7b) are isolation transformers, (8) is a recognition code voltage generation circuit, and (9) is a self-recognition code judgment@path. Note that the same reference numerals in the two figures indicate the same or equivalent parts.

Claims (1)

[Claims] An interface circuit for asynchronous serial data communication between first and second devices connected to each other by a cable including a grounding wire and a signal line, the interface circuit being provided in the first device and connected in series to the second device. a serial-to-parallel conversion circuit for transmitting and receiving data;
a serial-to-parallel conversion circuit for transmitting and receiving the serial data from the device via the signal line in synchronization with a synchronization signal in the data; a synchronization circuit capable of reading or generating a synchronization signal so that data can be transmitted and received in synchronization; and a synchronization circuit equivalent to that of the first device in the second device; An interface circuit comprising: a recognition code voltage generation circuit that generates a voltage of a self-recognition code of the device; and a self-recognition code determination circuit that can determine the self-recognition code of the second device in terms of voltage.