JPH02275558A - Electronic apparatus - Google Patents

Abstract

PURPOSE:To allow a general user to easily operate the electronic apparatus by driving a central controller by a command signal outputted from a daisy chain control part for automatically recognizing the using environments of plural units. CONSTITUTION:An inverter 14 outputs HI as a daisy out signal 12 when a daisy chain signal 11 is HI, and outputs HI as the daisy out signal 12 when the signal 11 is L0 and a request signal 13 is also L0. A negative logical AND circuit 15 outputs L0 as the daisy out signal 12 when the signal 11 is L0 and the signal 13 is HI. The circuit 15 is included in each of daisy chain control parts 25-1 to 25-3. It is previously determined that a circuit substrate including the daisy chain control parts 25-1 to 25-3 responds to a CPU 22 when the daisy chain signal 11 is L0 and the daisy out signal 12 is HI. Consequently, it is unnecessary to operate a jumper switch in each operation and a general user can easily operate the electronic apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device that recognizes the usage environment of a plurality of circuit units or circuit boards.

[Prior Art] It is common practice to configure electronic equipment using a circuit board on which a plurality of boards, a motherboard for electrically connecting them, and a central control unit (hereinafter referred to as CPU) are mounted. However, this is simply a mounting issue, and in addition to dividing the board, it can be used to later add only the necessary functions in response to diversified purposes such as personal computers. These additional boards are generally referred to as option boards, and by attaching them to a slot in a personal computer, the user can add the functions desired by the user.

Most common personal computers have four or six slots, and FIG. 4 shows a configuration with three slots. In such a usage environment, some of the plurality of circuit boards send a request signal to the CPtJ42 before starting their own special functional operation, such as an interrupt or bus acquisition to the CPU. These request signals are logically ORed to make a request to the CPU 42, and as a result, the CPU
When U 42 generates a response signal 48 indicating permission in response to the request, it causes the plurality of circuit boards 44-
It is necessary to recognize the usage environment so that each circuit board can determine which one of 1.44-2.44-3 it is for.

For convenience, a daisy-chain control unit 45-1.

45-2.45-3. Circuit board 44-L
44-2. Dage-chain control section 45 on 44-3
-1.45-2.45-3 are connected through the motherboard 46 by daisy signals 47-1.47-2.47-3. 50-1゜50-2.50-3 is a jumper switch that is used to close the jumper switch when the option board is not inserted into the connector 49-1.49-2.49-3 and the board is inserted into the corresponding slot. Let it open.

[Problems to be Solved by the Invention] As described above, in order to select only one circuit board from among a plurality of circuit boards, the daisy chain control unit in each board must be As seen in Figure 4, the out signal is located on the circuit board located to the right of it.
Must be connected to the chain control unit's daisy chain signal. As mentioned above, these circuit boards are added later and inserted into the slots only when necessary depending on the purpose of use. In this case, the slot position for insertion is limited due to daisy chain control. That is, in FIG. 4, the slots must be used in order starting from the left side. However, depending on the circuit board, it may only be possible to use a predetermined slot depending on the specifications, so the slot on the left side may not always exist. In order to prevent the daisy chain from being disconnected midway as in this case, generally a jumper switch is placed between the in and out of the daisy chain signal on the motherboard, and the board is inserted. Some users do not operate the jumper switch because it requires specialized knowledge and the jumper switch is located in a real space inside the personal computer. Things are difficult. Even if it were possible to operate it, it would be troublesome.

An object of the present invention is to provide a highly safe electronic device that can be partially operated by a user.

[Means for Solving the Problems] The present invention provides a central control device that controls a plurality of electronically connected removable electronic circuit units, and a database that automatically recognizes the usage environment of the plurality of units. - A chain control unit, characterized in that the central control unit is operated by a command signal from the control unit.

[Example] FIG. 1 shows a part of a circuit for implementing the present invention,
Reference numeral 16 denotes a request signal generator, which is a circuit that holds the level of the request signal until its own board is recognized. 14 is an inverter, daisy chain signal 11
When is HI, it outputs HI as the dage-out signal 12. Next, when the daisy-chain signal 11 is LO and the request signal 13 is LO, II is output as the daisy-out signal 12. 15 is negative logic AND
The circuit outputs LO as the daisy-out signal 12 when the daisy-chain signal 11 is LO and when the request signal I3 is Hr.

Such a circuit is the daisy chain control section 25-1 in FIG.
．． 25-2. It is provided inside the 25-3. Any one of the circuit boards 24-1.24-2.24-3 is connected to the CPU 22
The request signal 23 is output as LO, and as a result, CP
When U22 generates a response signal 26 at LO indicating that the request is granted, circuit board 24-1.2
4-2.24-3, the response signal 26 is the circuit board 24-
1.24-2.24-3 can be recognized by the daisy-chain control section in its own circuit board. That is, when the daisy-chain signal 11, which is the input signal to the daisy-chain control section in FIG. You can set it as .

Moreover, by doing this, the circuit board 24-1 in FIG.
．． 24-2. Even if the request signal 23 is output from two or more boards of 24-3 to the CPU 22 at the same time,
Since only one board satisfies the condition that the daisy-chain signal 11, which is an input signal to the daisy-chain control section of FIG. 1, is LO and the daisy-out signal 12 is HI, there is no conflicting response.

FIG. 2 shows an embodiment of the present invention which is further added to the circuit shown in FIG.
The purpose of the present invention is achieved by adding a resistance value of
Any number of circuits can be considered that are more stable due to the stable operation of the circuit or the ambient operating voltage conditions, for example, circuits that can withstand ambient temperature conditions by replacing resistors with active elements.

Next, Figure 3 shows the motherboard 37 with no circuit board inserted into the center slot, and the resistor group 33-1.33.
-2.33-3 and daisy chain control section 31-1.3
1-2 is shown. Here, the daisy chain control section 3
1-1.31-2 shows only the negative logic AND gate portion of the daisy-chain control section.

The values of the resistance group 33-1.33-2.33-3 will be explained. First, when the response signal 32 is input at the LO level, the signal 34 must be controlled to Hl or LO by the negative logic AND gate in the daisy-chain control section 31-1. Here, assuming that the negative logic AND gate is a circuit with a TTL compatible CMO3 structure, the human resistance of the negative logic AND gate in the next stage daisy chain control section 31-2 is very large. The output voltage of the negative logic AND gate (VO
H) = Output current at 2.7V (10H) = 0.4m
A. If the LO level of the response signal 32 = OV, then the resistor 3
The value of 3-1 is 6.7Ω or more, but from the standpoint of noise resistance, it is set to 6.7Ω. Further, when the level of the response signal 32 becomes LO and the output level of the negative logic AND gate in the daisy-chain control section 31-1 becomes LO, the resistor group 33-
Needless to say, the input terminal level of the negative logic AND gate in the next-stage daisy-chain control unit 31-2 becomes the LO level.

Next, the level of the response signal 32 is Hl, and the output level 34 of the negative logic AND gate in the daisy-chain control section 31-1.
When becomes HI, its voltage value 35.36 is the resistance 33-
Needless to say, if the value of 2.33-3 is set to <6.7 Ω, which is the same as that of the resistor 33-1, the voltage will be 2.7V or more.

As mentioned above, the jumper switch group 50-1 in FIG.
．． 50-2. 50-3 is connected to the fixed resistor group 33- as shown in Figure 3.
Even if it is replaced with 1.33-2.33-3, daisy chain control can be performed without contradiction.

[Effects of the Invention] According to the present invention, there is no need to operate a jumper switch each time, and general users can easily operate the jumper switch.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a daisy-chain control section according to the present invention. FIG. 2 is a schematic diagram showing an example of a circuit for implementing the present invention. FIG. 3 is a block diagram of a daisy-chain control section according to the present invention. FIG. 4 is a configuration diagram of a conventional electronic device composed of multiple boards having setting switches for daisy chain control on a motherboard. 11: Dage-chain signal 12: Dage-out signal 13: Request signal and above Figure 1

Claims (1)

[Claims] a central control unit that controls a plurality of electronically connected removable electronic circuit units; a daisy chain control unit that automatically recognizes the usage environment of the plurality of units;
An electronic device characterized in that the central control unit is operated by a command signal from the control unit.