Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output expansion
Patent
1997-09-05
2000-10-24
Lee, Thomas C.
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output expansion
710 13, 710 74, 710101, 710102, G06F 1314, G06F 1320
Patent
active
06138173&
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present inventions are related to I/O expansion devices that enable a system thereof to expand inputs/outputs by connecting it to parallel interfaces of PC/AT or the PC/AT-compatible personal computers (or parallel input/output connectors equivalent ot the parallel interfaces), and apparatus applied with I/O expansion devices and methods applied with the device and the apparatus.
BACKGROUND ART
As for desktop personal computers, their expansion is ordinarily carried out by inserting an expansion board in the body of the computers. As for the PC/AT or PC/AT-compatible personal computers, their expansion is ordinarily carried out to insert an expansion board based on so-called ISA bus standard into a bus slot. As for notebook-sized portable personal computers, an expansion board for the desktop personal computers can be installed by means of connecting an expansion box such as a docking-station.
Recently, the PCMCIA standard is established, and models that can be extended by inserting an IC card (called a PC card) suitable for this standard into the card slot are in the market.
In the case where the expansion is carried out by inserting the expansion board in the body like the desktop computers, a case of the body must be opened. This is troublesome and a difficult work for persons not having any knowledge of computer.
As for the portable personal computer, its advantage of portability was lost very much if it is connected to a docking-station, and extra expense is required to purchase the docking station.
An expansion method of inserting an IC card in accord with the PCMCIA standard into the card slot requires to purchase an expansion board for newly additional expansion, because a desktop computer does not ordinarily support the card slot. The PCMCIA standard has some restrictions of IC card size because it has been derived from the expansion memory cards. Therefore, the expansions with the IC card are limited.
To solve these problems, it is an object of the present inventions to provide I/O expansion devices for additional inputs and outputs without inserting the expansion board in the bus slot and inserting the IC card into the card slot, and apparatus and methods applying the devices.
And it is an object of the present inventions to apply for various uses and provide highly portable personal computers, by means of inserting into the body of the computers like the IC card to apply the I/O expansion device to them.
SUMMARY OF INVENTION
An I/O expantion device according to the present inventions enables to expand inputs and outputs of a personal computer by connecting it to a parallel interface of the personal computer, and includes a connector for connecting the inputs and outputs to a parallel interface; and an I/O expansion circuit connected to the connector, having data input to input four or five bit data in a first register equivalent to a data register in the parallel interface, data output to output four bit data to a second register equivalent to a status register in the parallel interface, and control input to input a signal from a third register equivalent to control register of a parallel interface,
wherein the I/O expansion circuit has a plurality of four bit input/output ports and a four bit data bus for transferring data between these input/output ports and data input or data output, and outputs four bit data provided form the data input to one of the input/output ports or outputs four bit data provided from one of the input/output ports to the data output according to control from the control input.
The I/O expansion device according to one aspect of this invention is connected to the parallel interface of the personal computer, and inputs and outputs of the personal computer are allowed to be expanded by selecting one of the input/output ports according to the control the control input, and executing reading and writing of the selected input/output port.
An I/O expansion circuit according to the present inventions has a plurality of four bit input/output p
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B.J. Freeman et al.,: "Microprocessor-to-microprocessor communications via an 8-bit data bus" IBM Technical Disclosure Bulletin., vol. 25, No. 10, Mar. 1983, pp. 5230-5235.
P. Oguic, "Carte E/S externe pour port parallel", Electronique radio Plans, No. 567, Feb. 1, 1994, pp. 43-47.
Lee Thomas C.
Perveen Rehana
LandOfFree
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