JPH0756852A - Extended interface circuit - Google Patents

Abstract

PURPOSE:To provide the extended interface circuit, which is provided with versatility and improves the convenience of mounting to a main body device or an extended device, concerning the extended interface circuit used for connecting the extended device to the main device. CONSTITUTION:An extended device 6 is provided with a circuit information holding part 12 for storing prescribed circuit data and an output part 13 for transmitting the circuit data stored in the circuit information holding part 12 to a main device 5 on the conditions that a prescribed output enable signal is received from the main device 5, and the main device 5 is provided with a reloadable electronic circuit 10 constituting an electronic circuit based on the circuit data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interface circuit for connecting a main body device and a device (extension device) other than the main body device in order to supplement or add the function of the main body device.

[0002]

2. Description of the Related Art In a personal computer, a workstation, or the like, when supplementing or adding the function of such a main body device, an expansion device having a predetermined function, such as a magnetic disk device or a video device, is connected via an appropriate interface. Need to be connected to the main unit.

Conventionally, the above-mentioned interface interposed between the main unit and the expansion unit corresponds to each expansion unit connected to the main unit by constructing the most suitable interface. It was provided by increasing the number of physical devices on the device side. For example, to connect a magnetic disk device (hard disk drive device, floppy disk drive device, etc.), it is necessary to provide an interface circuit of a predetermined standard, while to connect a video device, it is necessary to provide a predetermined video board. It was

Further, as described above, in order to provide the interface portion with versatility in the state where the interface circuit required by the expansion device is different, conventionally, there are some expansions which are supposed to be connected to the main body device. It is necessary to prepare a plurality of electronic circuits corresponding to the device in advance, and to provide a control device capable of detecting an electronic circuit required as an interface by a predetermined method and automatically switching it.

As such a control device, for example, there is a bus control device disclosed in JP-A-2-219160. This bus control device sends an interface detection signal to the expansion bus, interprets the interface signal returned from the expansion board, detects the type of the expansion board, and detects the type of the expansion board so that it matches the interface of the signal terminal of the expansion board. Interface detecting device that determines the interface of the above, and a bus transfer device that inputs and outputs information between the system bus and the expansion bus according to the determination result of the interface detecting device.

[0006]

However, in the above-mentioned conventional technique, the electronic circuit required for the interface differs depending on the combination of the main body device and the expansion device.
A plurality of interface circuits have to be provided in the main body device or the expansion device according to the connection mode between the main body device and the expansion device, and there is a drawback that versatility and convenience in mounting are lacking.

Further, as described above, even when the interface control device is provided, it is the same that a plurality of interface circuits need to be provided in the main device or the expansion device, which is a disadvantage of lacking convenience in mounting. was there.

The present invention has been made to solve such conventional problems, and provides an expansion interface circuit having versatility and improved convenience in mounting on a main body device or an expansion device. The purpose is to

[0009]

In order to achieve the above object, the present invention is an expansion interface circuit used for connecting an expansion device to a main unit, wherein the expansion device stores predetermined circuit data. The main body device is provided with a circuit information holding unit and an output unit for transmitting the circuit data stored in the circuit information holding unit to the main body device on condition that a predetermined output enable signal is received from the main body device. A rewritable electronic circuit that constitutes an electronic circuit based on the circuit data is provided.

Further, the invention according to claim 2 is a physical device in which the circuit information holding unit, the output unit, and the rewritable electronic circuit are separately provided without using the CPU of the main unit. It is composed.

Further, in the invention according to claim 3, the circuit data line for the output part to transmit the circuit data to the main body device is shared with the existing data line.

Further, the invention according to claim 4 is configured such that a reset signal output for a longer time than a transfer time of circuit data is used as the output enable signal.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In this embodiment, as shown in FIG. 1, a case where the main body device 5 and the expansion device 6 are connected by connectors 20 and 21 will be described. The main body device 5 of this embodiment corresponds to a personal computer, a workstation, or the like, as in the conventional case. The expansion device 6 corresponds to a device that complements or adds the function of the main body device 5, such as a magnetic disk device or a video device.

The extended interface circuit of this embodiment is
As shown in the figure, a rewritable electronic circuit 10 provided in the main body device 5 for holding predetermined circuit data received from the expansion device 6, and circuit information provided in the expansion device 6 and storing circuit data. The holding unit 12 and the output unit 13 that transmits the circuit data stored in the circuit information holding unit 12 to the main body device 5 at a predetermined timing.

When the rewritable electronic circuit 10 receives the circuit data stored in the circuit information holding unit 12 of the expansion device 6, the rewritable electronic circuit 10 forms an electronic circuit based on the circuit data.

The circuit information holding unit 12 is composed of a ROM and stores circuit data indicating what the appropriate interface circuit between the expansion device 6 and the main device 5 is.

The output section 13 rewrites the circuit data stored in the circuit information holding section 12 of the main body apparatus 5 on condition that the output enable signal (OE * signal) sent from the main body apparatus 5 is received. To the electronic circuit 10. The OE * signal is, for example, configured such that the main body device 5 is output for a predetermined time when the power of the main body device 5 is turned on. When this signal is, for example, "0", the output unit 1
3 is set to output the circuit data from the circuit information holding unit 12, the circuit information can be automatically transferred when the power of the main body device 5 is turned on. Also, OE
* The signal does not necessarily have to be specially set to operate the output unit 13, and a suitable existing signal (for example, a reset signal) can be used.

Further, the physical connection line (circuit data line) for the output unit 13 to transmit the circuit data from the expansion device 6 to the main body device 5 does not have to be provided separately from the existing data line such as the address line. Instead, such existing data lines can be used together. This is because the output unit 13 can switch between general data such as an address and circuit data for transmission under the condition that the OE * signal is received, and transmit the data without hitting the bus. For example, when the reset signal is used as the OE * signal as described above, the output unit 13 transfers the circuit data while the transmission of general data is stopped by the reset signal. In this case, in order to transfer the circuit data while the internal CPU of the main body device 5 is in the reset state, the reset signal must be set to be output for a time longer than the transfer time of the circuit data.

The main unit 5 used in this embodiment is
As shown in FIG. 1, a power controller 14 and a power-on switch 18 are provided. Further, it is assumed that the expansion device 6 is designed on the assumption that power is supplied from the main body device 5. The power-on switch 18 switches between "1" and "2" of the power permission signal according to the user's operation. The power supply control unit 14 inputs power supply power, and supplies power to the expansion device 6 when the power supply enable signal of the power-on switch 18 becomes “1”. Needless to say, when the operating power supply voltage of the expansion device 6 is different from the power supply voltage of the main body device 5, it is necessary to take a predetermined measure against latch-up.

Next, the operation of this embodiment will be described.
First, the power-on switch 18 of the main body device 5 is operated to set the power supply permission signal to "1", and power is supplied to the expansion device 6. Next, the main device 5 transmits an OE * signal to cause the circuit information holding unit 12 of the expansion device 6 to output the circuit data. Then, the rewritable electronic circuit 10 of the main body device 5
Is rewritten based on the received circuit data, and thereafter, general data such as an address is transmitted and received between the main body device 5 and the expansion device 6.

A clock is required to output the circuit data from the circuit information holding unit 12, and this clock has the same number of clocks as the clock supplied to the rewritable electronic circuit 10, as shown in the figure. To use. In this case, it is necessary to supply the clock while sufficiently considering the delay between the rewritable electronic circuit 10 and the circuit information holding unit 12.
In this way, the expansion interface circuit that connects the main body device 5 and the expansion device 6 can always be configured with an optimum electronic circuit. Although the present invention has been described above with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments.

[0022]

As described above, according to the present invention, in the expansion interface circuit, the expansion device receives the predetermined output enable signal from the circuit information holding unit storing predetermined circuit data and the main body device. By providing an output unit for transmitting the circuit data stored in the circuit information holding unit to the main body device under the condition of, and providing the main body device with a rewritable electronic circuit that configures an electronic circuit based on the circuit data, An optimum interface circuit can be constructed according to the combination of the main body device and the expansion device, and the versatility can be provided.

Further, since the interface circuit is constructed by rewriting the rewritable electronic circuit, it is not necessary to provide a plurality of interface circuits in the main body device or the expansion device, space saving can be realized, and convenience in mounting is improved. There is an effect that can be achieved.

According to the third aspect of the invention, the output interface is configured to share the circuit data line for transmitting the circuit data to the main unit with the existing data line, thereby providing the extended interface circuit. There is an effect that the extended interface circuit of the present invention can be used without providing a separate data line.

According to the fourth aspect of the invention, the reset enable signal output for a longer time than the transfer time of the circuit data is used as the output enable signal, so that the output enable signal is transmitted. There is an effect that the extended interface circuit of the present invention can be used without providing the structure in the main body device.

[Brief description of drawings]

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

[Explanation of symbols]

 5 Main device 6 Expansion device 10 Rewritable electronic circuit 12 Circuit information holding unit 13 Output unit 14 Power supply control unit 18 Power-on switch 20, 21 Connector

Claims (4)

[Claims] 1. An expansion interface circuit used for connecting an expansion device to a main body device, wherein the expansion device has a circuit information holding section for storing predetermined circuit data, and a predetermined output enable from the main body device. An output unit for transmitting the circuit data stored in the circuit information holding unit to the main body device on the condition that a signal is received is provided, and the main body device is a rewritable electronic device that forms an electronic circuit based on the circuit data. An extended interface circuit characterized by having a circuit. 2. The circuit information holding unit, the output unit and the rewritable electronic circuit are constituted by physical devices separately provided without using a CPU of the main body apparatus. The extended interface circuit according to 1. 3. The extended interface circuit according to claim 1, wherein the output unit shares a circuit data line for transmitting circuit data to the main unit with an existing data line. 4. The extended interface circuit according to claim 1, wherein the output enable signal is a reset signal that is output for a time longer than a transfer time of circuit data.