JPH0746750B2 - Electronic circuit - Google Patents

Description

The present invention relates to the configuration of an electronic circuit, and more particularly to the configuration of an electronic circuit suitable for measuring the matching with a control system controlled by a CPU.

[Conventional technology]

When controlling a controlled system with a CPU, it is often practiced to change a program to optimally control the system. Program changes are generally storage elements
There are many cases of ROM replacement, and a simple method for such replacement is, for example, as disclosed in Japanese Patent Laid-Open No. 59-155194, an IC socket for an electronic circuit element that is expected to be replaced is provided on the electronic circuit board in advance, and if necessary There is a method of attaching and detaching the electronic circuit element from the IC socket and replacing it.

[Problems to be solved by the invention]

However, since the IC sockets mentioned above are not always manufactured by the same manufacturer as the electronic circuit element, the contact surface between the socket and the lead of the electronic circuit element may have a contact failure due to a slight dimensional difference, such as the lead spacing, or contact. Contact failure may occur due to oxidation of the surface. Even if they are the same manufacturer, the probability of contact failure is quite high, and it is often found that this causes the system to be out of control. In particular, when these control systems control the internal combustion engine, the probability of contact failure due to vibration or temperature change is further increased.

On the other hand, when the IC socket is not used, a special device is required to replace the electronic circuit element soldered to the board, and it is especially difficult to change the mass-produced product after the change.

An object of the present invention is to provide a method for constructing an electronic circuit in which electronic circuit elements can be easily replaced without impairing reliability.

[Means for solving problems]

The present invention relates to an electronic circuit in which a first electronic circuit element having a plurality of lead terminals and having a plurality of lead terminals is connected to a plurality of circuit conductors printed on a circuit board, and a plurality of connection conductors are connected to the circuit conductor. A switching circuit that has a terminal, and switches the first electronic circuit element and the second electronic circuit element by connecting the second electronic circuit through the connection terminal, This can be achieved by stopping the predetermined operation of the first electronic circuit element and arranging the second electronic circuit element to perform the predetermined operation.

[Action]

According to such a configuration, when a new electronic element is required, if the connection terminal provided on the new electronic element is connected to the board-shaped terminal, control can be performed by the new electronic element.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration before assembling two electronic circuit elements of the present invention, and FIG. 2 is a diagram showing a configuration after assembling the electronic circuit elements. In FIG. 1, a plurality of circuit conductors 2 and 2'are printed on the circuit board 1, and the first electronic circuit element 3 having a plurality of pins is soldered on the conductors 2 and 2 '. It is electrically connected. The electronic circuit element 3 is a memory circuit such as a ROM. Also, 4, 4'is the conductor 2,
The connector is pre-soldered on 2'and its enlarged perspective view is shown in FIG.

On the other hand, the second electronic circuit electrons 5 are configured to be electrically connectable to the auxiliary circuit board 7 on which a plurality of circuit conductors 6 and 6'are printed by soldering or the like. The pin connectors 8 and 8'are electrically connected to the circuit conductors 6 and 6'on the auxiliary board, and the pins 9 and 9'at the lower end of the pin connectors 8 and 8'are the connector 4 and 6 '. It is inserted and fixed in the 4'pin hole 10. The pin connector 8, 8'inserted and fixed in the connector 4, 4'is shown in FIG. When the pin connectors 8 and 8'are inserted and fixed to the connectors 4 and 4'fixed to the circuit board 1 side, use of a connector having a hook mechanism and a pin connector prevent both from coming off. Is possible. In addition, the pins 9 and 9'of the pin connectors 8 and 8'are soldered to the circuit conductors 2 and 2'on the circuit board 1 side without using the connectors 4 and 4 ', so that the electrical connection is more reliable. Will increase the sex.

As described above, the connectors 4, 4'which are electrically connected to the first electronic circuit 1 in advance and fixed on the circuit board 1 and the auxiliary circuit board 7 to which the pin connectors 8, 8'are fixed are provided. Then, when the operation of the first electronic circuit is changed (for example, the storage content of the ROM or the like is changed), the changed second electronic circuit 5 is fixed on the auxiliary circuit board, and the second electronic circuit 5 is fixed by the connector. If the first and second electronic circuits are electrically connected, the operation of the electronic circuit can be changed easily, and malfunction due to poor contact or stop of system control can be performed because the socket is not used. It is possible to prevent such a serious accident.

When the above-mentioned second electronic circuit is electrically connected to the first electronic circuit element, a selection circuit for stopping the operation of the latter electronic circuit element and switching to the former electronic circuit element is required.

FIG. 4 is a block diagram of the selection circuit. In FIG. 4, the first electronic circuit element 3 is provided on the side of the circuit board 1 described above.
(ROM-1 in the fourth embodiment), a CPU 11 and an AND circuit 13 which is a first selection circuit are provided. Further, the auxiliary circuit board 7 is provided with, for example, a second electronic circuit element 5 whose operation content is changed (ROM-2 whose storage content is changed in the embodiment) and an AND circuit 14 which is a second selection circuit. The data address 12 is connected between the CPU 11 and the first electronic circuit element 3, and further connected to the second electronic circuit element 5 via the connector described above. Similarly, the CPU 11 and the second selection circuit 14 are also connected via a connector.

Next, the selection operation of the two electronic circuit elements will be described. CPU11
A15, which is the most significant bit terminal of the address bus, the output terminal E of the system lock, and the output of the AND circuit 13 which receives the signal from the power supply Vcc as the chip select terminal ▲ ▼ of the first electronic circuit element 3. Is entered. The chip select terminal (1) is selected by activating the first electronic circuit element 3 when all three inputs of the AND circuit 13 are at high level. This state is the case where the second electronic circuit element 5 is not yet connected, and data communication is performed only between the CPU 11 and the first electronic circuit element 3. On the other hand, if the system is changed and the necessity of changing the program of the first electronic circuit element 3 arises, after the changed second electronic circuit element is attached to the auxiliary circuit board 7, the auxiliary circuit board 7 is attached. Is fixed on the circuit board 1 via the pin connectors 8 and 8'and the connectors 4 and 4 '. The Vcc power input of the AND circuit 13 on the circuit board 1 is configured to be grounded on the auxiliary board via the connectors. Therefore, the power input of the AND circuit 13 becomes low level, the chip select terminal (1) of the first electronic circuit element 3 becomes low level, and this element is not selected. At the same time, the chip select terminal ▲ ▼ of the second electronic circuit element 5 receives only the output signals from the A15 and E terminals from the CPU 11 via the AND circuit 14,
The electronic circuit elements are connected by a connector, and when the system is powered on, they are automatically selected and activated.

FIG. 5 is a diagram showing another embodiment of the present invention. In the embodiment shown in FIG. 1, the pin connectors 8 and 8'also serve as conductors for electrically connecting the first and second electronic circuits 3 and 5 and fixing members for fixing the electronic circuit board 7 to the circuit board 1. In the embodiment of FIG. 5, however, the flat cables 15, 15 'are used to connect the two electronic circuits, and the fixing member 16 fixes the two substrates. The flat cables 15 and 15 'are mounted by curving between the two substrates so that, for example, the lower side in the drawing is mechanically freed to have a spring effect. Further, the fixing member 16 is provided with a locking mechanism for preventing the fixing member 16 from coming off from the substrate. With this configuration, the electrical connection portion can avoid mechanical stress, and it is possible to prevent disconnection, contact failure, etc. of the connection conductor caused by mechanical vibration, thermal expansion, or the like.

As described above, according to the present invention, when it is necessary to use the second electronic circuit element that performs the modified predetermined operation instead of the operation of the first electronic circuit element, these elements need to be exchanged with each other. Instead, the purpose of the operation change can be easily achieved by stacking and connecting the second electronic circuit elements three-dimensionally using the connector. Conventionally,
The IC socket, which was considered to be versatile, had a high probability of contact failure due to the difference in the cross section of the IC lead section, the structure of the socket section, etc. Since the space on the substrate adopts a three-dimensional stacking system, there is no particular change. Further, since switching to the added second electronic circuit element can be automatically performed, it is not necessary to add a circuit for that purpose.

By appropriately selecting the signal from the CPU 11 as the input signal of the AND circuit 14 provided on the auxiliary circuit board 7, for example, when the second electronic circuit element 5 is a ROM, the memory of the element 5 is stored. It is also possible to add capacity.

〔The invention's effect〕

As described above, according to the configuration of the present invention, even if the electronic circuit is changed, the electronic circuit element can be replaced without using the IC socket, so that a reliable control circuit can be realized even after the replacement.

[Brief description of drawings]

1 and 2 are views for explaining a method for constructing an electronic circuit according to the present invention, FIG. 3 is a partially enlarged perspective view of one component shown in FIGS. 1 and 2, and FIG. FIG. 5 is a circuit configuration diagram showing another embodiment. 1 ... Circuit board, 3 ... First electronic circuit element, 4 ... Connector, 5 ... Second electronic circuit element, 7 ... Auxiliary circuit board, 8 ... Pin connector, 11 ... CPU, 13 , 14 …… and circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahisa Suda 2520 Takaba, Takata, Katsuta City, Ibaraki Pref., Sawa Plant, Hitachi, Ltd. (56) Reference JP-A-57-145396 (JP, A) 54-9363 (JP, U) Actually opened 61-146974 (JP, U)

Claims (1)

[Claims] 1. An electronic circuit in which a first electronic circuit element having a plurality of lead terminals and having a plurality of lead terminals is connected to a plurality of circuit conductors printed on a circuit board, the plurality of circuit conductors being provided on the circuit conductor. And a switching circuit for switching between the first electronic circuit element and the second electronic circuit element by connecting a second electronic circuit through the connecting terminal. An electronic circuit characterized in that the circuit stops the predetermined operation of the first electronic circuit element and causes the second electronic circuit element to perform the predetermined operation.