JPH02101561A - Connecting system between main electric circuit and additional electric circuit by connector - Google Patents

Abstract

PURPOSE:To reduce the number of the poles of a connector, and to reduce the cost of production by providing a switching means by which a main electric circuit receives a discrimination signal through the connector and switches the connection or the operation of a circuit element so as to adapt itself for an additional electric circuit. CONSTITUTION:When a circuit A 1 as the main electric circuit and the circuit B 2 as the additional electric circuit are connected by the connector 3, power is supplied from a circuit A 1 side, and levels determined beforehand are set in the signals S1 to Sm of the circuit B 2. The set levels are supplied to the switching means 4 of the circuit A 1 through the connector 3, and one of them is selected. The selected signal connects a partial circuit of coupling the circuit A with the circuit to output the signals I1 to Il of the circuit B and performing some processing function. Thus, the number of the poles of the connector to be used for connection can be curtailed, and the cost of production can be reduced.

Description

[Detailed Description of the Invention] [Summary] At least one additional electrical circuit arbitrarily selected from a plurality of additional electrical circuits is connected to the main electrical circuit using a connector, and the selection is used to perform various processing functions. Regarding the connection method, the configuration of the additional electric circuit is not restricted by the configuration of other additional electric circuits, thus increasing the degree of freedom in design, and reducing the number of connector pins used for connection, thus reducing manufacturing costs. This is a connection method that selectively connects the main electric circuit and multiple additional electric circuits using connectors, in which the additional electric circuits receive power from the main electric circuit. an identification signal generating circuit for supplying an identification signal to the main electrical circuit, the main electrical circuit receiving the identification signal via the connector and connecting or operating circuit elements so that the main electrical circuit is compatible with the additional electrical circuit; It is configured to include a switching means for switching.

[Industrial Application Field] The present invention connects at least one additional electrical circuit arbitrarily selected from a plurality of additional electrical circuits to a main electrical circuit using a connector, and connects the main electrical circuit to perform various processing functions depending on the selection. Regarding the method.

Although devices in recent years have become highly multi-functional, some of them may not be used by some users. Therefore, many devices do not provide these user-limited functions as basic functions of the device, but rather allow the user to add them later as options that can be freely selected. Methods of adding functionality include replacing the control microprogram of the device, but when changing the hardware, it is necessary to configure the main electrical circuit of the device with hardware that realizes the optional function. A circuit board (hereinafter referred to as circuit B) that constitutes an additional electric circuit separate from the circuit board (hereinafter referred to as circuit A).

When the functions of circuit B are required, circuits A and B are commonly used by connecting them with a connector or the like. Specific examples include making various character fonts for various display devices and printers optional, supplying only the necessary character fonts by adding a circuit equipped with a ROM in which character fonts are written, and providing graphs and images. A method is used in which printing and display functions such as these are made optional, and the circuits for processing these data are configured on a separate board and attached to the main board using the necessary connectors. The present invention relates to a method for connecting circuits A and B in this field.

[Conventional technology]

In a method where a part of the hardware is made optional and is installed by connecting it with a connector etc. when necessary, providing a separate dedicated connector for each option is because separate mounting space must be secured. Therefore, it is not used much. In many cases, the signal lines required by various optional circuits are designed to be common, so that multiple types of circuits can be arbitrarily connected to one connector. However, in this method, the design of the option circuit is constrained by the specifications of other option circuits, and the degree of freedom in design is limited.

Apart from this, a method is also used in which signal lines such as connectors are defined separately for each option circuit, and each option circuit is used by connecting only the necessary signal lines such as connectors. According to this, since the signal lines necessary for each option circuit can be arbitrarily defined, the design of the option circuit is not restricted by the specifications of other option circuits. However, this method has the disadvantage that since a signal line dedicated to each option circuit must be prepared separately, the number of poles of the connectors, etc. used increases, leading to an increase in manufacturing costs.

[Problem to be solved by the invention]

The present invention aims to solve the problems of the conventional system in which the configuration of an optional circuit as an additional electric circuit is restricted and the number of pins of the connector used increases.

An object of the present invention is to increase the degree of freedom in design by not restricting the configuration of an additional electric circuit to the configurations of other additional electric circuits, and
Another object of the present invention is to provide a connection method between a main electric circuit and an additional electric circuit, which reduces the number of connector pins used for connection and thus makes it possible to reduce manufacturing costs.

[Means to solve the problem]

In the present invention, as illustrated in FIG. 1, a main electrical circuit 1 and at least one of a plurality of additional electrical circuits are selected and connected using a connector 3 to perform various processing operations. system, the additional electric circuit 2 is the main electric circuit 1
The main electric circuit 1 is provided with an identification signal generation circuit that is supplied with power from the connector 3 and supplies an identification signal to the main electric circuit.
A method of connecting the main electric circuit and the additional electric circuit by means of a connector is provided, which is equipped with a switching means 4 for switching the connection or operation of circuit elements so that the main electric circuit 1 is compatible with the additional electric circuit 2 in response to the identification signal via the connector. be done.

[For production]

If the above-mentioned method is used, as illustrated in FIG.
) is connected with the connector 3, power is supplied from the circuit A side (not shown), and a predetermined level (high level or low level) consisting of S1 to SII of circuit B is set. This set level is supplied via the connector 3 to the switching means 4 to the circuit, whose outputs SA to S
One of Z is selected, and the selected signal transmits the selected signal to a circuit in circuit B (eg, a circuit that transmits an OAL signal from OA) to a circuit in circuit B (eg, I.

(1) to a circuit that outputs signals from (1) to (2), it is possible to perform a processing function in which circuits A and B are combined.

[Example] A circuit diagram of a device using a method of connecting a main electrical circuit and an additional electrical circuit using a connector as an embodiment of the present invention is shown in FIG. 1, and a circuit diagram of another embodiment is shown in FIG. Circuit diagrams of more specific embodiments are shown in FIGS. 3 and 4.

In FIG. 1, circuit A is the main electrical circuit and is the main body circuit of the device, and circuit B is an optional circuit as an additional electrical circuit connected to circuit A via connector 3. In circuit A, OA,, DAt,..., 0
At-t, OAL, DBI, 01h, ..., 0Bt-
++OBL”・, DYL, OYz, ..., 0
YL-1, OYL, OZl, OZl ”・.

ozt-,, oz are signals output to circuit B, and the signals (0^+, OAg,..., 0At-+, OAt
), signal (OB,, OB,, -.

0BL-1,0BL),"',Signal (DYL, OYz
, ..., 0Yt-+, 0Yt), signal (OZl, D
Zt..., 0ZL-1, OZL) are a group of signals each output to a separate option circuit. Signal OA
,,OA! ,..., 0At-+, OAt are respectively 3-state buffers D811DAz+..., DAL
-1, Output to connector 3 through DAL, signal OB
,,OB,,...,0Bt-++OBt are 3-state buffers DBI, DBI,..., oat-, respectively.
Output to connector 3 through 1+DBL, signal oy,
.

DY2. ..., 0YL-1OYL are 3-state buffers DY,, DY,, ..., DYL-1, respectively.
, DYL is output to connector 3, and the signal OZ+
, OZt, "・, 0Zt-++OZt are each 3
State”' 77 y DZ + + DZ z
+ ... + 02 t - t + DZ It is output to the connector 3 through t. DA,,DB, ,...D
Y, , mouth Z, (n=1.2..., 14, 1
) outputs are connected in common. In circuit B,
RV, , RV, . . . RVI-, , RVL are receivers for receiving the signals supplied through the connectors, and their outputs are the signals 1, . . . , respectively. , I2. ...+
It becomes IL-1+ 11 and is supplied to the components of circuit B. Signal S, , S, ,...+5ll-
1+ general is the identification signal of circuit B, driver SD,.

SD2. ..., is output to the connector through SD, l, and SD. In circuit A, this identification signal is connected to a decoder (F) 4, and these signals S, , S
t,...5ll-1+ Depending on the state of Sea (high level or low level), the output signal SA of the decoder F,
SB,..., sy.

One of Sz becomes low level. signal SA,
S.B.

..., sy, sz are each group of 3-state buffers (OA, DA, ..., DAL-
1, DAL), (DBI, DB2...
Dh-+, DBt) ,... (DY,, DY,,
..., DYL-1, DYL), (DZ,, mouth Zt
s..., DZL-1, DZL) (7) Connected to the enable input. Each driver outputs an input signal when the enable input is at a low level, and becomes high impedance when the enable input is at a high level.

Identification signal of circuit B (S+, Sz,..., 5la
-li S, ), then the signals SA, SR of circuit A.

..., sy, sz becomes low level. Only the three-state buffers to which this signal is connected to the enable input are enabled, and the only signals input to that driver are circuit B's signals 11+I2.・
...r b-++ It is output to It. For example, the identification signals S+, h, ...+ Sl@-IT S
If the signal SA becomes low level due to the state of e, the three-state buffer D8l+DAl+..., DA
Only the output of L-1+DAL is enabled, and the other 3-state buffers DB, , DBI, ... DBL-1, DB
L l", DYL, Dh,", DYt-++D
Yt, DZt.

The outputs of DZ, . . . , DZL-1 and DZL become high impedance. Therefore, the signal II r lf of circuit B
f1 +...+ lt-In1, respectively, are circuit A
The signals OA+, OAz, ..., OA, -,.

OA is output. Identification signals S+, SZ, ”
', S-+.

If this changes to a different state and the signal SZ becomes low level,
3-state buffer DZ,, DZ,..., DZL-
Only the output of 11DZ is enabled, and the other 3-stage amplifiers DA, , DAD, ..., DAt-+,
DAt, DBI, DBz,...

DBL-1, DBL, ..., DYL, Dh,
..., DYt-+, DYt (7) The output becomes high impedance. Therefore, the signals L, IK, of circuit B are
...+IL-1+IL is the signal OL of circuit A, respectively.
, OZz, -, 0Zt-+, OZt are output.

As described above, according to this embodiment, the identification signal S+ + 52 +...r 5s-1+ Sya from the circuit B
Since the signal from circuit A can be switched depending on the state of , the signals S, , S, , .
. . , S, −□ is assigned another state, and the signal to which each option circuit is assigned is constantly identified as a signal S, ,
By outputting to S, , . . . +511-1+S, I, the signal assignment can be switched for each option circuit. Therefore, each option circuit is
It is possible to design without being restricted by the signal definitions of other optional circuits, and there is no need to use a connector with a large number of pins.

The above explanation has been made regarding the case where a signal is transmitted from circuit A to circuit B, but the same can be considered for a signal transmitted from circuit B to circuit A, and this example is shown in FIG. It will be done.

Each name in FIG. 2 is the same as in FIG. 1.

However, the 3-state buffers OA+ and DAz on circuit A
.

..., DAL-1,0AL, DB+, DBt
,..., DBt-tIDBt,...DYI,
DYZ, = , DYt-+, DYt, DZ+
, DZz, -, DZt-0021 are in the direction of inputting the signal from circuit B, and their output is the signal ■8I+I
A2+..., IA, -,, IA, IB+1IB-z
,..., IBt-+, IBt,..., IL,
IYz,..., IYt-+.

IYL, IZ+, IZg,..., IZt-1
, IZt. Also, from circuit B, signal O1
, 0□, ..., 0L-1101 are drivers DV, , DV2., 0L-1101, respectively. ..., OV and -□DV are output to the connector. If the signal Sl + S
2+...r 5ll-11s, SA depending on the state of I
If the signal becomes double the low level, the 3-stage amplifier DA,
, to D2. ..., DA+-+.

Only DA is enabled, and the other 3-state buffer DB
,,DB,,...,DBL-1,DBL,...
, DY, , DY2. ..., DY, -,.

DYL, DZ+, D2h,..., DZL-1, D
ZL has high impedance. Therefore, the signals from circuit B are 08,0□,...0°1,0. is the word IA
It is output only to L-111AL to I, Ilh, ..., ■. Similarly, the signal Sl+St from circuit B,...
・, S□3. Depending on the state of S, the output signals 01, 0□, ...+0L-1+ot from circuit B are assigned to each signal group (IA+, IAz, ..., ■^L-1.IAL)
, (IB, IBI.

..., IBI-,, IBL), ... (
IY+, IYz, ..., IYL-111Y, ),
(IZ+, IZzs", IZt-+, lZt)
The output is switched between two.

The embodiments shown in FIGS. 3 and 4 will be described.

Circuit A in FIGS. 3 and 4 is the same circuit.

In FIG. 3, option circuit B1 is connected to circuit A, and in FIG. 4, option circuit B2 is connected to circuit A. Circuit A
In this case, there is only one identification signal from circuit B1 or circuit B2, and this signal is sent to the three-state buffers OA+ and DA.
It is connected to the enable input of z and Dlh. The identification signal is inverted by an inverter F', the output of which is connected to three-state buffers DB+, DBz, and DB3. In FIG. 3, the identification signal of the circuit B1 is always output at a low level by grounding the input of the driver DS that outputs the identification signal. At this time, circuit A
In , the three-state buffers OA, DAz, Dh whose low level enters the enable input are enabled, and the three-state buffers DBI, DB2 . . . whose high level enters the enable input through the inverter F'. DB:l becomes a high impedance state. Therefore, the signals OA, OA2 of circuit A
is the signal L, through the receiver old, ,Dh of circuit B1.
It is output to the circuit Bl as Iz. Signal 0 of circuit B1
3 is a driver D03 and a 3-state buffer Dlh
It is output to the signal 11h of circuit A through. 3-state buffer DB2. When Dlh becomes a high impedance state, the signals IB and 183 become unstable, so the resistance RB
It is pulled up by z and RBz to take a high level.

In FIG. 4, the identification signal of the circuit B2 is output at a high level by pulling up the input of the driver DS that outputs the identification signal with a resistor R. In this circuit A, the 3-state buffers DA+, DAz, and DAt enter the enable input at a high level, and are in a high impedance state, and the 3-state buffers DB+, DBt, and DB3, which enter the enable input at a low level through the inverter F', become enabled. . Therefore, the signal OB of circuit A is sent to circuit B through the three-state buffer DB and the receiver DI. On the other hand, the signals of circuit B2 are output as 0□, 0.
are Drino\DOz respectively.

The signals are output to circuit A as signals IBz and IBz through DOl and 3-state buffers DBz and DBz.

When the 3-state buffer DA3 enters a high impedance state, the signal 11h becomes unstable, so it is pulled up by the resistor RA3 to take a high level.

In this way, in circuit B1 and circuit B2, the signals OA, O1h, IA3 and OB+, IJ, IB3 on circuit A are
Can be used by switching. As in the switching between the signal OAZ and the signal I82 in this example, it is not only possible to switch between the output signals and the input signals (but also between the input signal and the output signal).

As described above, the present invention defines a common signal for identifying the type of option circuit as part of the connection signal between the main electric circuit and the option circuit, that is, the additional electric circuit, and uses this signal to identify the type of the option circuit in the main electric circuit. It is used to switch lines.

FIG. 5 is a perspective view illustrating a case where the present invention is applied to a laser printer 51. In the figure, a cartridge 54 is, for example, an image processing circuit cartridge, a cartridge 55 is a character font ROMI cartridge, and a cartridge 56 is a character font ROM2 cartridge, which are used by being attached to the main body as shown by broken lines.

6 and 7 show circuit A and circuit 8 of the embodiment.
A perspective view of the case where the first and the like are configured on a printed circuit board is shown.

[Effects of the Invention] According to the present invention, the configuration of an additional electric circuit is not restricted by the configuration of other additional electric circuits, and the degree of freedom in design is increased, and
By reducing the number of connector pins used for connection, manufacturing costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a device using a method of connecting a main electric circuit and an additional electric circuit using a connector as an embodiment of the present invention, and Fig. 2 is similar to Fig. 1 of another embodiment of the present invention. FIGS. 3 and 4 are circuit diagrams illustrating still other embodiments, FIG. 5 is a perspective view of a laser printer to which the present invention is applied,
6 and 7 are perspective views of a device according to an embodiment of the present invention constructed on a printed circuit board. In the diagram, ■...Circuit A, 2...Circuit B, 3...
- Connector, 4... Decoder.

Claims (1)

[Claims] A connection method for selectively connecting a main electric circuit (1) and a plurality of additional electric circuits (2) using a connector (3) to perform different processing operations, the additional electric circuits ( 2) comprises an identification signal generating circuit that receives power from the main electrical circuit (1) and supplies an identification signal to the main electrical circuit, and the main electrical circuit receives the identification signal via the connector. A method of connecting a main electrical circuit and an additional electrical circuit by means of a connector, comprising a switching means (4) for switching the connection or operation of a circuit element so that the main electrical circuit is compatible with the additional electrical circuit.