JPH0426904Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention is used in the field of interface circuits that handle digital signals.

The present invention relates to an interface circuit capable of parallel and bidirectional transmission.

(b) Prior Art An RS-232C interface circuit is known as a serial, bidirectional transmission system. Also, in parallel,
As a unidirectional transmission method, the Centronics standard is used for printers, for example.

(c) Problems to be solved by the invention RS-232C has a slow data transfer rate because it is a serial transmission method, and requires complicated settings for the baud rate.

Second, Centronics's use is limited because it is unidirectional. Furthermore, in parallel transmission systems based on this standard, bidirectional buffers are often used to reduce the number of signal lines. In this case, a time difference occurs in direction switching, noise voltage is likely to occur due to signal collision, and unless strict timing design is performed, malfunctions are likely to occur. moreover,
Designing relay buffers and signal terminations is also difficult, placing a heavy burden on software.

The purpose of this invention is to adopt a parallel transmission method that has a high transfer rate and is easy to connect without adjustment, and also incorporates a bidirectional transmission method to ensure stable operation with all data signal lines operating in one direction, either input or output. It is an object of the present invention to provide an interface circuit that can be expected and therefore facilitates circuit design and software design.

(d) Means for solving the problem The above purpose is to provide an output circuit consisting of a plurality of data signals, a strobe signal, a busy signal, and an extension signal for transfer control, and a signal having the same configuration as above. This is achieved by arranging the signal terminals of the output circuit and the signal terminals of the input circuit completely symmetrically with respect to the center of the end face of the connector portion.

(e) Effect With the RE-232C, the signal arrangement of the connector differs between the computer or terminal side and the modem side, so it may be necessary to set a switch to change the signal arrangement depending on the type of connected device. Furthermore, when connecting devices with the same signal arrangement, it is necessary to rearrange the signals using cables, which confuses users. Therefore, each signal on the transmitting side and the receiving side is arranged completely symmetrically, the signal arrangement on the equipment side is the same regardless of whether it is a computer or a peripheral device, and the connectors at both ends of the connecting cable are always connected in reverse arrangement.
Therefore, the correspondence between the signal output terminal and the signal input terminal becomes clear.

(F) Embodiments A preferred embodiment of the present invention will be explained based on the drawings.

FIG. 1 is a schematic end view of a connector showing one embodiment thereof and a detailed view of its terminal arrangement. This illustrated example is a 36-pin standard connector.
This is applied to AMPHENOL/DDK plugs and jacks. As shown in the figure, the terminal arrangement between the 8-bit data input and output signals is symmetrical with respect to the center C of the connector.

FIG. 2 is a cable connection diagram according to the embodiment of FIG. The B side signal name is omitted, but if you look at the terminal number, you can see that the B side output signal corresponds to the A side output signal.
You can see that the input signal on the side is connected.

FIG. 3 is a diagram showing the relationship between terminal numbers and signal names of a 50-pin connector (plug and jack) showing another embodiment, and FIG. 4 is a diagram showing the connection relationship between the terminals.

FIG. 5 is a diagram illustrating handshake timing of the interface circuit according to the present invention. Compared to conventional Centronics standard devices, there is no ACK signal terminal, but this terminal is rarely used, and the interface circuit of the present invention can also be connected to Centronics standard devices. In that case, it is necessary to change the signal line arrangement of the cable.

Also, as in the illustrated example, it has EXO/EXI signals. This is 1 bit in addition to 8 bit data.
Bit extension signals are available. Using this, it is possible to distinguish between data and commands,
Any binary data other than character codes can be efficiently transmitted. 8-bit data alone would require software using special sequences, but this effort is eliminated. It can also be used for other purposes, in which case it does not need to be synchronized with the output signal DnO.

FIG. 6 is an exemplary diagram of the standard input/output circuit of the interface circuit according to the present invention.

Furthermore, FIG. 7 is a diagram illustrating an application example of the interface circuit according to the present invention.
The data bidirectional operation mode between the CPU and the interface circuit will be understood.

(g) Effects Transfer speed is fast, it can be used without adjustment, the signal terminals between input and output are arranged symmetrically, making connection easy, and all data signal lines can be used for unidirectional input or output operation. This has the effect that stable operation can be expected, and that circuit design and software design are also facilitated.

[Brief explanation of the drawing]

Figure 1 shows one embodiment of the present invention, the upper part is an end view of the 36-pin interface connector, the lower part is its terminal arrangement table, and Figure 2 is the cable connection table of Figure 1. Figure 3 is a 50-pin connector terminal arrangement table, Figure 4 is the cable connection table of Figure 3, Figure 5 is an example of handshake timing according to the present invention, and Figure 6 is a standard input/output circuit according to the present invention. The example diagram, FIG. 7, is a diagram illustrating an application of the present invention. C is the center of the interface connector end face.

Claims (1)

[Scope of utility model registration request] It is composed of an output circuit consisting of a plurality of data signals, a strobe signal, a busy signal, and an extension signal for transfer control, and an input circuit consisting of signals of the same configuration as above, and the signal terminal of the output circuit and the input An interface circuit characterized in that the signal terminals of the circuit are arranged completely symmetrically with respect to the center of the end face of the connector part, and parallel and bidirectional transmission is possible.