JP2574540B2 - Data interface device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data interface device, and more particularly, to a data interface device for a microcomputer (hereinafter referred to as a microcomputer) for transmitting and receiving digital data through a data transmission path.

[0002]

2. Description of the Related Art FIG. 2 shows a schematic configuration of a conventional data interface device of this kind.

That is, in the configuration of the conventional apparatus shown in FIG. 2, reference numerals 31 and 41 denote respective microcomputers on the own side and on the other side, and reference numerals 32 and 42 denote data interfaces (I / F) of these microcomputers 31 and 41. ICs, each of which is a buffer amplifier (hereinafter, referred to as Buf) 33, 43
, Auto gain control amplifiers (hereinafter referred to as AGC amplifiers) 34 and 44, amplifiers (hereinafter referred to as AMPs) 35 and 45, and detectors (hereinafter referred to as DEs).
T) 36 and 46). and again,
The microcomputer 31 on its own side is connected to a data transmission path 39 via a Buf 33, a capacitor 37, and a transformer 38 in order, and similarly, the microcomputer 41 on the other side
f43, the capacitor 47, and the transformer 48 are connected to the data transmission path 39 in this order.

Next, the operation of the conventional device will be described. The digital data signal output from the microcomputer 31 on its own side is transmitted to the Bu of the data I / F IC 32 on its own side.
At f33, the output signal is converted from a low or high output signal to a data signal in which the reference voltage is constant at the time of low and the amplitude is centered on the reference voltage at the time of high, and the DC component is cut by the capacitor 37. The data is transmitted to the data transmission path 39 by the connection of the transformer 38.

The data signal passing through the data transmission line 39 is amplified by the AGC amplifier 44 of the data I / F / IC 42 on the other side via the transformer 48 and the capacitor 47, and the data signal is amplified by the AMP 45. After being amplified to a detectable level, the low and high data signals detected by the DET 46 can be input to the microcomputer 41 on the other side. This is the transmission of the digital data signal from the other side to the own side. Is exactly the same.

On the other hand, each microcomputer 3 on the own side and the other side
1 and 41 themselves, the digital data signals output from them are respectively Buf33 and 43 in the data I / F IC 32 and 42 on the own side and the other side,
The signals can pass through the AGC amplifiers 34 and 44, the AMPs 35 and 45, and the DETs 36 and 46, and can be input to their own input pins.

That is, as described above, even in the conventional data interface device, the microcomputer can arbitrarily transfer its own data and data from another microcomputer.

[0008]

However, in the conventional data interface device having the above configuration, the data level at the input of the AGC amplifier at the time of transmission to the microcomputer on its own side and the AGC at the time of reception from the microcomputer at the other side are different.
Because there is a difference between the data level at the amplifier input,
There is a problem in that it is not possible to correctly identify data by the AGC amplifier from noise, data distortion due to other external components, and the like.

An object of the present invention is to solve such a conventional problem and to provide a data interface device capable of accurately transmitting data between microcomputers. .

[0010]

In order to achieve the above object, a data interface device according to the present invention is provided with a signal level detection circuit in a data I / F / IC to output a data signal to its own microcomputer. Sometimes, the gain of the AGC amplifier is suppressed,
It is designed to correspond to the output of the C amplifier.

That is, the present invention relates to a data interface device for a microcomputer, comprising: a buffer amplifier for converting a digital data signal input from a microcomputer on its own side into a voltage having an amplitude around a reference voltage; Means for transmitting the output to the other microcomputer, the buffer amplifier, or an auto gain control amplifier for amplifying only a certain amplitude of a signal from the other microcomputer, and a digital signal from the own microcomputer. A signal level detection circuit that detects a signal level of a data signal and suppresses an amplification factor of the auto gain control amplifier, an amplifier that amplifies an output of the auto gain control amplifier to a detectable value, and detection of an output of the amplifier. Do Te is a data interface device, characterized in that it comprises a detector for inputting the detection output to the host side of the microcomputer.

[0012]

According to the present invention, the following functions are provided by the above configuration.

That is, the data signal from the microcomputer on its own side is output with a reduced amplification factor of the auto gain control amplifier because there is no data loss due to the data transmission path, while the data signal from the microcomputer on the other side is output. In order to cause data loss through the data transmission path, the amplification factor of the auto gain control amplifier is increased and the data is output. By this, the level of the correct data signal in the amplifier and the detector later than this is output. Can be adjusted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a data interface device according to the present invention will be described below in detail with reference to FIG.

FIG. 1 is a schematic block diagram showing a configuration of a data interface device to which one embodiment of the present invention is applied.

That is, also in the configuration of the embodiment apparatus shown in FIG. 1, reference numerals 11 and 21 denote respective microcomputers on the own side and the other side, and reference numerals 12 and 22 denote respective microcomputers 1 and 2.
Bufs 13 and 23 for converting digital data signals into a voltage having an amplitude around a reference voltage, and AGC amplifiers 14 and 24 for amplifying only a certain amplitude or more. The AGC amplifier 1 detects the signal level of the digital data signal.
Signal level detection circuits (hereinafter referred to as SL) 15 and 25 for lowering the gains of the AGC amplifiers 1 and 24;
AMP that amplifies the output of 4, 24 to a detectable level
16 and 26, and DET for detecting the output from the AMPs 16 and 26. Also here, the microcomputer 11 on the own side is connected to the data transmission path 20 via the Buf 13, the capacitor 18, and the transformer 19, and similarly, the microcomputer 21 on the other side is
It is connected to data transmission path 20 via Buf 23, capacitor 28, and transformer 29.

Next, the operation of the above conventional device will be described. The digital data signal output from the microcomputer 11 on its own side is output from the low and high output signals by the Buf 13 of the data I / F / IC 12 on its own side, When the reference voltage is constant and high, the data signal is converted into a data signal having an amplitude at the center of the reference voltage, and the DC component is cut by the capacitor 18 and transmitted to the data transmission line 20 by the coupling of the transformer 19. Is done.

In this case as well, the data signal transmitted through the data transmission path 20 is transmitted through a transformer 29 and a capacitor 28 by the AGC amplifier 24 of the data I / F / IC 22 on the other side at a certain level as a boundary. Only the signal that is determined to be is amplified and amplified to a level detectable by the AMP 26, and then the low and high data signals detected by the DET 27 can be input to the microcomputer 21 on the other side. The same applies to the transmission of a digital data signal from the other side to the own side.

On the other hand, regarding each of the microcomputers 11 and 21 on the own side and the other side, the digital data signals output from the respective microcomputers 11 and 21 are converted into data I / F ICs 12 and 22 on the own side and the other side. Buf13,23 in
Are sent to the AGC amplifiers 14 and 24 via the channel. At this time, if the digital data signal is high,
The amplification factors of the AGC amplifiers 14 and 24 are suppressed by 15 and 25, and in this state, they can be input to their own input pins through the AMPs 35 and 45 and the DETs 36 and 46, respectively.

As described above, in this embodiment,
When transmitting a digital data signal from the microcomputer 11 on its own side to the microcomputer 21 on the other side, even if the digital data signal is transmitted at a large value in consideration of the loss in the data transmission path 20, the digital signal to the microcomputer 11 on its own side can be transmitted. When transmitting the data signal, the signal level of the AGC amplifier 14 is suppressed by the SL 15, so that the signal level is made equal to the signal level transmitted from the microcomputer 21 on the other side through the data transmission path 20. Here, more accurate data transfer becomes possible.

[0021]

According to the present invention, as is apparent from the above embodiment, when the data signal is output to the local microcomputer,
A signal level detection circuit for suppressing the amplification factor of the GC amplifier is provided so that the output of the AGC amplifier at the time of outputting the data signal can correspond to the output of the AGC amplifier at the time of receiving from the other microcomputer. The difference between the data level at the output of the AGC amplifier at the time of transmission to the microcomputer and the data level at the output of the AGC amplifier at the time of reception from the microcomputer on the other side can be eliminated, so that the data signal can be accurately transferred. You get
In addition, here, there are excellent features such as easy selection of external constants such as AMP and DET.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of a data interface device to which an embodiment of the present invention is applied.

FIG. 2 is a schematic block diagram showing a configuration of a conventional data interface device.

[Explanation of symbols]

 11, 21 Microcomputer 12, 22 Data interface / IC 13, 23 Buffer amplifier 14, 24 Auto gain control amplifier 15, 25 Signal level detection circuit 16, 26 Amplifier 17, 27 Detector 18, 28 Capacitor 19, 29 Transformer 20 Data transmission path

Claims (1)

(57) [Claims] 1. A data interface device for a microcomputer, comprising: a buffer amplifier for converting a digital data signal input from a microcomputer on its own side into a voltage having an amplitude centered on a reference voltage; Means for transmitting to the microcomputer, the buffer amplifier, or an auto gain control amplifier for amplifying only a certain amplitude or more of the signal from the microcomputer on the other side, and a signal of the digital data signal from the microcomputer on the own side. A signal level detection circuit that detects a level and suppresses the amplification factor of the auto gain control amplifier, an amplifier that amplifies the output of the auto gain control amplifier to a detectable value, and detects the output of the amplifier, Before the detection output A data interface device comprising: a detector for inputting data to a microcomputer on the data storage side.