US 5,848,292 AGranted

System for data transmission between a wedge microcontroller and a personal computer microcontroller by disconnecting the keyboard microcontroller and placing the same in hold state

AssigneeNCR Corporation

InventorRobert H. Nathan

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Abstract

A system for interfacing at least one peripheral device with a personal computer is disclosed as including a personal computer microcontroller, a keyboard microcontroller directly connected to the personal computer microcontroller by means of a clock line and a data line, a switching device positioned between the personal computer microcontroller and the keyboard microcontroller, and a wedge microcontroller to which the peripheral device may be connected. The wedge microcontroller further includes a first set of connections to the clock and data lines positioned between the switching device and the keyboard microcontroller, a second set of connections to the clock and data lines positioned between the switching device and the personal computer microcontroller, and a switch control connection to the switching device for opening and closing the switching device. The direct connection between the personal computer microcontroller and the keyboard microcontroller can be disabled by opening the switching device so that the wedge microcontroller may input data from the peripheral device into the personal computer microcontroller.

Claims17

Dependent claims

A system for interfacing at least one peripheral device with a personal computer microcontroller, comprising:

(a) a personal computer microcontroller;
(b) a keyboard microcontroller directly connected to said personal computer microcontroller by means of a clock line and a data line;
(c) a switching device positioned between said personal computer microcontroller and said keyboard microcontroller;
and
(d) a wedge microcontroller to which said peripheral device is connected, comprising:
(1) a first set of connections to said clock and data lines positioned between said switching device and said keyboard microcontroller;
(2) a second set of connections to said clock and data lines positioned between said switching device and said personal computer microcontroller;
and
(3) a switching device control connection to said switching device for opening and closing said switching device;
wherein the direct connection between said personal computer microcontroller and said keyboard microcontroller is disconnected by opening said switching device so that said wedge microcontroller is able to transmit data to said personal computer microcontroller;
wherein said keyboard microcontroller is actively prevented from transmitting data to said personal computer microcontroller during transmission of data from said wedge microcontroller to said personal computer microcontroller, by said wedge microcontroller sending a signal to said keyboard microcontroller via said clock line that places said keyboard microcontroller in a hold state, for as long as the wedge microcontroller is transmitting data to said personal computer microcontroller.

8 more elements

A method of transmitting data from a wedge microcontroller to a personal computer microcontroller, wherein said personal computer microcontroller is directly connected to a keyboard microcontroller by means of a clock line and a data line with a switching device positioned therebetween, said wedge microcontroller including a first set of connections to said clock and data lines between said switching device and said keyboard microcontroller and a second set of connections to said clock and data lines between said switching device and said personal computer microcontroller, said method comprising the steps of:

(a) determining whether said wedge microcontroller has data to be transmitted to said personal computer microcontroller;
(b) monitoring said data line between said keyboard microcontroller and said personal computer microcontroller;
(c) opening said switching device when no activity is detected on said data line;
(d) transmitting data from said wedge microcontroller to said wedge microcontroller to said personal computer microcontroller;
and
(e) actively preventing said keyboard microcontroller from transmitting data to said personal computer microcontroller during transmission of data from said wedge microcontroller to said personal computer microcontroller, by said wedge microcontroller sending a signal to said keyboard microcontroller via said clock line that places said keyboard microcontroller in a hold state, for as long as the wedge microcontroller is transmitting data to said personal computer microcontroller.

3 more elements

Dependencies are inferred from the claim text.