JPH0675719A - Interface control system - Google Patents

Abstract

PURPOSE:To simplify a software constitution which can secure the connection of many peripheral devices via a single control circuit by monitoring at one time the state transitions of all status signals including an extension status signal. CONSTITUTION:A controller 109 controls a printer 108 equivalent to a peripheral device via an interface. When the printer 108 starts a print job under the control of the controller 109, the state of a status signal 110 is first read and a fact that the printer 108 has no fault is confirmed. Then the state of the signal 110 is written into a comparison register 101. When the printer 108 has a fault and the state of the signal 110 is changed, a comparator 102 detects the discordance between the signal 110 and the register 101. Then an interruption circuit 103 generates an interruption on a processor 106. Thus the state transition of the signal 110 can be simply detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device in an information processing system such as a workstation which is composed of a control device for controlling a peripheral device such as a printer through an interface and a peripheral device to be controlled. The present invention relates to an interface control method on the side, and particularly to an interface control method suitable for enabling connection of many types of peripheral devices having different functions of an extended status signal by one control circuit.

[0002]

2. Description of the Related Art As an interface for controlling a peripheral device such as a printer, for example, an interface manufactured by Centronics Co., Ltd. is widely used. There is a status signal for expansion in the interface, and a specific specification of the peripheral device is defined. It may have been. For example, a status signal indicating the power state of a peripheral device may be defined as an extended status signal in some devices, or may be assigned to a different signal line in some devices. In such a case, the controlling software must properly use the signal according to the function of the extended status signal.

Since the conventional status monitoring means has not taken into consideration the extended status signal, the signal necessary for detecting the state transition must be checked by software as needed. Therefore, when connecting various types of peripheral devices, the structure of software for controlling becomes very complicated.

As a countermeasure therefor, there is a method in which a hardware switch is attached and the interface is changed by switching the switch. However, malfunctions due to operation mistakes when operating the switch and time loss during setup were problems.

In addition to this, there is a system as shown in Japanese Patent Laid-Open No. 61-180328. However, since it is necessary to have a type signal on the cable of the peripheral device to be connected, and the types of devices that can be supported are limited, the versatility of the interface was poor.

[0006]

SUMMARY OF THE INVENTION An object of the present invention as set forth in claim 1 is to monitor a state transition of all status signals including an extended status signal at a time so that one control circuit can control peripheral devices. Types are also to simplify the structure of the controlling software when connecting.

At the same time, hardware that eliminates operational mistakes and time loss when operating the switch, and is compatible with a large number of peripheral devices having different extended status signal functions regardless of the presence or absence of a type signal on the cable. To provide.

An object of the present invention as set forth in claim 2 is to make the status signal to be monitored selectable in the invention as set forth in claim 1 so as to be able to deal with detection of a specific state transition.

[0009]

The invention described in claim 1 is
The interface control circuit on the control device side has latch means for storing a state at a certain time of all status signals including extended status signals having different functions depending on the type of peripheral device, and a status signal stored in the latch means. A status monitoring means is provided which comprises a comparing means for comparing the state with the actual status of the status signal at any time, and an interrupting means for generating an interrupt when a mismatch occurs in the comparing means.

According to a second aspect of the invention, in the interface control system according to the first aspect, there is provided selection means for selecting a status signal to be monitored by software.

[0011]

In the latch means according to the first aspect of the present invention, the states of all status signals at that time are stored, and the state of the status signal stored in the latch means is compared with the actual state of the status signal. Compare by means. Then, when a state transition occurs in any of the status signals, the comparing means detects the disagreement and the interrupt means causes an interrupt. Thereby, the state transition can be easily detected.

At this time, since the state transition of an arbitrary status signal can be detected, it is not overlooked even if the function of the extended status signal is different. Therefore, it is not necessary to check the required signal by software any time, and the structure of the controlling software is simplified.

Further, unlike the prior art, it is not necessary to mount a hardware switch for switching the interface signal, so that the operation error and time loss which occur when operating the switch are eliminated. Furthermore, since the type signal is not used, it is possible to deal with peripheral devices that do not have the type signal.

As a result, the versatility of the interface is greatly improved.

By the way, the present invention has the advantage that the versatility of the interface is improved because all status signals are monitored at once, but since even state transitions of irrelevant status signals are detected, only certain specific status signals are detected. Not suitable if you want to monitor.

Therefore, in the invention of claim 2, the selecting means for selecting the status signal monitored by the status monitoring means by software is provided. This makes it possible to ignore the state transition of the irrelevant status signal, so that it is possible to deal with specific state transition detection.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a typical embodiment of the invention of claim 1.

The control device 109 controls the printer 108 corresponding to the peripheral device via an interface manufactured by Centronics. The processor 106 and the main memory 107 are connected to the internal bus 105 of the control device 109.
The processor 106 is executing processing according to the above program.

In the figure, 101 is a comparison register corresponding to the latch means, and 102 is a comparison circuit corresponding to the comparison means. Further, 103 is an interrupt circuit corresponding to the interrupt means, 104 is a status signal input from the printer 108.
It is a synchronization circuit for internally synchronizing 110. Here, it is assumed that the status signal 110 includes the extended status signal.

When the control device 109 starts printing on the printer 108, it first reads the status of the status signal 110 and confirms that the printer 108 has not failed. next,
The state of the status signal 110 is written in the comparison register 101. In this embodiment, the steps up to this point are performed by software.

When a failure or the like occurs in the printer 108 and the status signal 110 is switched, the comparison circuit 102 detects a mismatch between the status signal 110 and the comparison register 101,
The interrupt circuit 103 causes the processor 106 to generate an interrupt.

Since the comparison circuit 102 compares all the status signals 110, it is possible to detect which status signal 110 is switched. As a result, state transitions can be detected even in peripheral devices having different extended status signal functions.

The embodiment shown in FIG. 2 is a method in which the setting of the status state in the comparison register 101, which is performed by software in the embodiment of FIG. 1, is automatically performed by hardware.

In this method, the state of the status signal 110 is read by software as in the above-mentioned embodiment, and at the same time, automatically transferred to the comparison register 101. Hereinafter, the same operation as that of the above-described embodiment is performed and the same effect is obtained.

FIG. 3 shows an embodiment of the invention shown in claim 2.

The control circuit of FIG. 3 is obtained by adding a selection register 301 corresponding to the selection means to the embodiment shown in FIG. The status signal 110 to be compared by the comparison circuit 102 is selected by the selection register 301.

For example, when the state is to be monitored with the expectation that the fault will be released after the occurrence of a fault, the selection register 301 is set so as to select the status signal 110 indicating the fault, and the status signals 110 other than that are set. You can leave it unselected. As a result, other state transitions are not interrupted until the target failure is released.

When it is desired to monitor a plurality of status signals 110 at the same time, if those status signals 110 are selected at the same time on the selection register 301, an interrupt occurs at any one of the status transitions.

[0029]

According to the interface control system of the invention described in claims 1 and 2 described above, the versatility to the peripheral devices having different functions of the extended status signal is significantly improved.

Further, since it is not necessary to provide a switch,
Eliminates operational mistakes and time loss that occur when operating the switch.

Furthermore, since the type signal is not used, it is possible to connect peripheral devices that do not have the type signal.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of an interface control system according to the present invention.

FIG. 2 is a block configuration diagram of an embodiment in which a comparison register is automatically set in relation to the embodiment of FIG.

FIG. 3 is a block diagram of another embodiment of the interface control system according to the present invention.

[Explanation of symbols]

 101 ... Comparison register, 102 ... Comparison circuit, 103 ... Interrupt circuit, 104 ... Synchronization circuit, 105 ... Internal bus, 106 ... Processor, 107 ... Main memory, 108 ... Printer, 109 ... Control device, 110 ... Status signal, 301 … Selection register.

Continuation of the front page (72) Inventor Tadashi Kyoda 810 Shimoimaizumi, Ebina City, Kanagawa Prefecture Hitachi Office System Design and Development Center

Claims (2)

[Claims] 1. In an information processing system such as a workstation, which comprises a control device for controlling a peripheral device such as a printer through an interface and the peripheral device to be controlled, an interface control circuit on the control device side is provided. Latch means for storing the status of all status signals including extended status signals having different functions depending on the type of peripheral device, and status of the status signal stored in the latch means and actual status signal status By providing a status monitoring means composed of a comparing means for constantly comparing and the above and an interrupt means for generating an interrupt when a mismatch occurs in the comparing means, the state transition of peripheral devices having different functions of the extended status signal can be performed. Interface control method that can be easily detected 2. The interface control method according to claim 1, wherein the status monitoring means is provided with a selection means for selecting a status signal to be monitored by software so that the status monitoring means can also detect a specific state transition. Characteristic interface control method