JPH09244916A - Controller and inspection device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a CPU inexpensive and to lower a cost by providing a communication port for an inspection device other than the communication port with an EEPROM in the CPU in the case of connecting the inspection device to a controller provided with the CPU and the EEPROM and inspecting it. SOLUTION: The inspection part 7 of this inspection device 5 is connected to communication lines 41 and 42 through a switching circuit 6 to be OFF when the EEPROM 3 is selected by signals from a chip selection port 23. Also, communication to the EEPROM 3 and the communication to the inspection device 5 are alternatively performed by a pair of the communication ports.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device suitable for inspecting the control device by connecting the inspection device to the control device for controlling the equipment and the inspection device therefor.

[0002]

2. Description of the Related Art A control device for controlling equipment is provided with a CPU for performing arithmetic processing and an EEPROM for storing data and the like. The CPU and the EEPROM have communication ports connected to each other via a communication line to communicate data and the like. However, the CPU and the EEPROM are not always in communication, but the chip select ports provided in each are connected via the select line so that communication is performed only when the chip select port on the CPU side is in the high state. Has become. On the other hand, when the device is shipped from the factory or at the time of maintenance after shipping, it is necessary to inspect whether or not the control device is normal by using an inspection device separate from the control device. For the inspection, the inspection device must be connected to the control device and communication must be performed between the inspection device and the control device. Therefore, the CPU is provided with a communication port for connecting the inspection device in addition to the communication port for connecting the EEPROM.

[0003]

The communication port provided in the CPU for connecting the above-mentioned inspection device is used only at the time of shipping or maintenance as described above, and therefore the frequency of use is extremely low. On the other hand, if you increase the communication port to the CPU, C
The cost of the PU becomes high, and it is uneconomical to provide a dedicated communication port for such an infrequently used application.
In addition, in the state where the inspection device and the CPU are communicating, C
There is no communication between the PU and the EEPROM and the communication port for the EEPROM is not used.

Therefore, in view of the above problems, the present invention provides C
An object of the present invention is to provide an inspection device that can inspect a control device even if the PU does not have a dedicated communication port for the inspection device.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is a control device for controlling equipment, comprising a CPU and an EEPROM, wherein a communication port of the CPU and an EEP
The communication port of the ROM is mutually connected via a communication line, and the chip select port of the CPU and the EEP
A switching circuit having a control terminal connected to the select line, in which communication is performed via the communication line when the chip select port of the ROM is mutually connected via the select line and the chip select port of the CPU is high And an inspection device that can be connected to a communication line through a switching circuit and inspects the control device by communicating with the CPU, only when the high signal is not input to the control terminal. It is characterized in that communication between the control unit and the control unit is possible.

Further, in a control device for controlling the equipment, which comprises a CPU and an EEPROM, the communication port of the CPU and the communication port of the EEPROM are connected to each other via a communication line, and the chip select port of the CPU And an EEPROM chip select port are connected to each other via a select line, and an inspection device for inspecting what communicates via a communication line when the CPU chip select port is high is used. And a control unit that can be connected to a communication line via a switching circuit, and a control terminal that can be connected to a select line is provided in the switching circuit, and a high signal is supplied to the control terminal. The feature is that the communication between the inspection unit and the control unit is enabled only when is not input.

The inspection device is connected to the communication line to which the EEPROM is connected and is also used as the communication port of the CPU. However, the inspection device and the EEPROM are EEPR
OM is given priority, and the inspection device is cut off from the CPU by the switching circuit so that the inspection device cannot access the CPU while the EEPROM and the CPU are communicating. still,
The chip select port is kept low during the communication between the inspection device and the CPU of the control device.

By the way, the switching circuit may be provided on either the control device side or the inspection device side.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to FIG. 1, reference numeral 1 denotes a control device which is provided in equipment such as a gas appliance and controls the operation of the equipment. The control device 1 includes a CPU 2 that performs arithmetic processing for control and an EEPRO that communicates between the CPU 2 and the CPU 2.
And M3 are provided. The CPU 2 is provided with a pair of communication ports 21 and 22 for inputting and outputting communication signals. Similarly, the EEPROM 3 is also provided with a pair of communication ports 31 and 32. And the communication port 21
・ 22 and communication ports 31 and 32 are communication lines 41.4
2 are connected to each other. CPU2 and EEPR
OM3 and chip select ports 23 and 33, respectively
Both chip select ports 23 and 33 are provided.
Are mutually connected via a select line 43.
When communicating with the EEPROM 3, the CPU 2 first switches the chip select port 23 from low to high. In this way, communication can be performed between the EEPROM 3 and the CPU 2 while the chip select port 23 is switched to high.

By the way, it is necessary to inspect whether the control device 1 can operate normally when the device is shipped from the factory or at the time of maintenance. For the inspection, an inspection device 5 separate from the equipment is connected to the control device 1, a predetermined signal is sent from the inspection device 5 to the CPU 2, and a response to the signal is received to determine whether the control device 1 is operating normally. To inspect. The inspection device 5 comprises a switching circuit 6 and an inspection unit 7.
The switching circuit 6 includes input / output ports 61 and 62 and a control terminal 6
3, the input / output ports 61 and 62 are connected to the inspection unit 7 when the control terminal 63 is in a state other than high, and the input / output port 61 and 62 are connected when a high signal is input to the control terminal 63.
It is configured to cut off between 62 and the inspection unit 7. Therefore, when the input / output ports 61 and 62 are connected to the communication lines 41 and 42 respectively and the control terminal 63 is connected to the select line 43 as shown in the figure, the CPU 2 and the EEPR are connected.
Since the select line 43 is high while the communication with the OM 3 is being performed, the inspection unit 7 uses the communication line 41.
・ The EEP is blocked against 42 and prior to the inspection device 5.
Communication is performed between the ROM 3 and the CPU 2.

As described above, the case where the inspection device 5 is connected and the control device 1 is inspected is a special case such as when the device is shipped from the factory or at the time of maintenance. Therefore,
For example, the inspection switch 11 is provided on the device side, and when the power switch (not shown) is turned on, the inspection switch 11
If the chip select port 23 is forcibly held low by turning on the
Communication is not performed with the PROM3, and the communication port 21.
The control device 1 can be inspected by communicating with the inspection device 5 using 22.

In the above embodiment, the switching circuit 6 is provided in the inspection device 5, but as shown in FIG.
Ordinary inspection device 5 provided on the first side and provided with the inspection unit 7
May be connectable to the switching circuit 6.

[0013]

As is apparent from the above description, according to the present invention, both the communication with the EEPROM and the communication with the inspection device can be selected even if the CPU has only one pair of communication ports. If the CPU has two pairs of communication ports as in the conventional case, the remaining one pair of communication ports is used for another purpose, for example, communication with another control device. be able to. If it is not necessary to use it for other purposes, it is an inexpensive C with a pair of communication ports.
It can be replaced with a PU, and the cost of the control device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of another embodiment of the present invention.

[Explanation of symbols]

 1 Control Device 2 CPU 3 EEPROM 5 Inspection Device 6 Switching Circuit 7 Inspection Unit 41 Communication Line 42 Communication Line 43 Select Line

Claims (2)

[Claims] 1. A control device for controlling equipment, comprising a CPU and an EEPROM, the communication port of the CPU and E
The EPROM communication port is connected to each other via a communication line, and the CPU chip select port and E
A switching circuit having a control terminal connected to the select line, in which communication is performed via the communication line when the chip select port of the EPROM is mutually connected via the select line and the chip select port of the CPU is high And an inspection device that can be connected to a communication line through a switching circuit and inspects the control device by communicating with the CPU, only when the high signal is not input to the control terminal. And a control unit that enables communication between the control unit and the control unit. 2. A control device for controlling equipment, comprising a CPU and an EEPROM, the communication port of the CPU and the E
The EPROM communication port is connected to each other via a communication line, and the CPU chip select port and E
In an inspection device for inspecting what is communicated through a communication line when a chip select port of an EPROM is mutually connected through a select line and the chip select port of a CPU is high, a switching circuit and a CPU Equipped with an inspection unit that communicates between devices to inspect the control device and that can be connected to a communication line via a switching circuit.The switching circuit has a control terminal connectable to the select line, and a high signal is output to the control terminal. An inspection device for a control device, which enables communication between the inspection unit and the control unit only when no input is made.