JPH03150657A - Line system among input devices - Google Patents

Abstract

PURPOSE:To transmit data from each input device to a host computer without causing collision with each other by raising a request to send by the input device and sending the data from it when permission to send arrives, and transferring the permission to send to a lower order input device from a host input device when there is no request to send in the host input device itself and in addition, the permission to send arrives at it. CONSTITUTION:At the time of transmission from some terminals, for instance, the terminal 13, the request to send RS is raised, and when a host receives it and returns the permission to send CS, this is transferred and reaches the terminal 13 if the terminals 11,12 of the higher order than the terminal 13 are not in the course of the transmission, and since the terminal 13 is raising the request to send, this is never transferred to the lower order terminal 14. Accordingly, only the terminal 13 acquires a sending right, and th other terminals never send the data. Thus,the data from each terminal can be transmitted to the host computer without causing the collision with each other on a data line 2.

Description

[Detailed Description of the Invention] [Summary of the Invention] In a system in which a plurality of input devices are connected to a host computer, the present invention relates to a line system between the input devices for transmitting data transmitted from each input device to the host computer without causing collision, In a system configuration in which input devices are connected, the purpose is to transmit data from each input device to the host computer without causing collisions, and it is possible to connect multiple input devices to the host computer in series or in parallel. In a line system between input devices in a system, a data line, a transmission request line, and a transmission permission line are provided between a host computer and multiple input devices, and the input device issues a transmission request and sends data when transmission permission is granted. death,
The higher-level input device is configured to transfer it to the lower-level input device when there is no request for transmission and permission to transmit is received.

[Industrial application field]

The present invention relates to a line system between input devices for transmitting data from each input device to the host computer without causing collision in a system in which a plurality of input devices are connected to a host computer.

In recent years, input terminals for computers such as personal computers have been required to include various input devices such as keyboards, ten-key keyboards, mice, joysticks, and card leagues. In addition, each input device is becoming more intelligent.
There is a demand for connecting input devices in series/parallel to the host to reduce the burden on the host compared to the case where these input devices are connected to the host individually.

(Prior Art) Conventionally, as shown in FIG.
3. A plurality of terminals 13a having only hardware functions, such as 13a and 13b.

13b is connected to a common terminal 13 having a controller function, and this terminal 13 is connected one-to-one to a host computer. The terminals 13a and 13b are, for example, a mouse and a card league, and the terminal 13 is a keyboard. The terminal 13 even controls the terminals 13a and 13b.

[Problem to be solved by the invention]

When multiple terminals are connected to a host computer in a one-to-one ratio, connectors equal to the number of terminals are required in each convenience store, and data input/output control must be performed by software using these connectors as I10 ports. Control with the comviator becomes complicated.

Connect multiple input devices in series or parallel and connect them to one
If you treat it as @end and connect to the host, the burden on the host will be reduced. However, in this case, data collision between terminals is a problem.

An object of the present invention is to enable data from each input device to be transmitted to a host computer without causing collision in a system configuration in which such input devices are connected.

[Means to solve the problem]

As shown in FIG. 1, in the present invention, a host computer l and a plurality of input devices (@end) 11, 12, 13, . . .
- A data line 2, a transmission request line 3, and a transmission permission line 4 are provided in between.

When transmitting data, each terminal raises a transmission request R3 to the transmission request line 3, and when a transmission permission C8 comes from the transmission permission line 4, it sends the data to the data line 2.

Transmission permission AI? I4 connects the host computer and each terminal in cascade, and in this connection order, the host side is the upper one, and the opposite side is the lower one. When the higher-level terminal does not receive a transmission request (and receives a transmission permission C3 from an even higher-level terminal),
Transfer it to the lower terminal.

[Effect]

According to this configuration, no data collision occurs. That is, when a certain terminal, for example, the terminal 13, sends a transmission request R
When the host receives this and returns a transmission permission C8, this is transferred to the terminal 13 if the terminal 11 or 12 higher than the terminal 13 is not transmitting, and the terminal 13 issues a transmission request. Therefore, only terminal 13 obtains the transmission right, and other terminals do not send data, and each terminal transmits data on data line 2. data will never collide.

The priority order of data transmission is the order in which the devices are connected by the transmission permission line, and by changing this, the priority order can be changed.

〔Example〕

The operation of the system of FIG. 1 will now be described in detail.

When using the line: When the transmission request signal R3 is issued from another terminal, do nothing and proceed to processing other than the next data transmission; when the transmission request signal R3 is not issued from another terminal It sends a transmission request signal R3 (request) and waits for a transmission permission signal C3 (chip select). When the signal C3 comes, the data is sent to the host, and when the sending is completed, the signal R3 is lowered. If the signal C3 does not come even after waiting for a predetermined period of time, the signal R3 is lowered and the process proceeds to the next step.

When granting transmission permission to a lower-level terminal: When a lower-level terminal issues a transmission request, the own terminal is not in use (transmitting), and transmission permission is received from a higher-level terminal, the lower-level terminal is permitted to transmit. For example, in the case of the terminal 12, if a transmission permission C3I is received from the upper terminal 11, the transmission permission C32 is sent to the lower terminal 13.
send. The transmission permission signal sent to the lower terminal is restored when the lower terminal lowers its transmission request.

Terminals 11, 12. The main components of ...... are shown. Each terminal has a control processor 20, which is connected to a data line 2, a transmission request line 3, a transmission permission line 4, and input/output covers 21-25.

These lines 2-4 are pulled up to the power supply VCC by resistors. TO is a connection terminal to a higher-order terminal, and TD is a connection terminal to a lower-order terminal. In the configuration shown in FIG. 2, each terminal appears to be connected in series (actually, in parallel with the data line and transmission request line, and in series with the transmission permission line).

Data is sent from the terminal to the data line 2 via the output buffer 21 when the terminal receives transmission permission C3.

, the status of the transmission request line 3 (H/L level status) is constantly monitored by the processor 20 via the input buffer 22.
When the line is in use, the processor 2o outputs a transmission request signal R3 to the transmission request line 3 via the output buffer 23.

The status of the transmission permission line 4 (H/L level state) is monitored by the processor 2o via the input buffer 24, and the transfer to the lower terminal is performed via the output buffer 25.

If the host side does not require transmission permission/distortion control for each terminal (reception is possible at any time), it is sufficient to always output the transmission permission signal C3O and leave the transmission request line 3 open at the post. , this eliminates the need for any control on the host side.

Typically, there is one each of lines 2-4, so the data is transmitted serially. Further, the H/L level of the transmission request/permission line is L active.

This method allows easy system expansion. That is, terminal TU
, TD, it can be easily expanded by simply connecting the terminal TU of the terminal to be added to the terminal TD of the existing terminal using a signal line.

If permission to send is not received even after raising the sending request, the sending request is lowered and the process proceeds to the next step.This means that there was a key input on the keyboard, so when I tried to send it, permission to send did not come. , then move on to the next key input process, and if you prepare a buffer, this will be sufficient.

〔Effect of the invention〕

As explained above, according to the present invention, even when a plurality of input devices are connected to each other, data can be reliably transmitted without forcing the host to perform complex control, simplifying the system configuration and making it flexible for system expansion. We can respond.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a block diagram showing a conventional example. In FIG. 1, 2 is a data line, 3 is a transmission request line, 4 is a transmission permission line, l is a host, 11, 12 . . . . is an input device. Principle diagram of the present invention Block diagram showing an embodiment of the present invention Fig. 2

Claims (1)

[Claims] 1. In a line system between input devices in a system in which a plurality of input devices can be connected to a host computer in series or in parallel, a data line (two
), a transmission request line (3), and a transmission permission line (4) are provided, and the input device raises the transmission request (RS) and sends permission (CS).
A line system between input devices characterized in that the upper input device transmits data to the lower input device when there is no request for transmission to the upper input device and permission for transmission arrives.