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

• US 5,848,292 A
• Filed: 06/19/1996
• Issued: 12/08/1998
• Est. Priority Date: 06/19/1996
• Status: Expired due to Term

• Current Assignee: NCR Corporation
• Original Assignee: NCR Corporation
• Inventors: Nathan, Robert H.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): Kim, Ki S.
• Application Number:
  US08/666,163
• Time in Patent Office: 902 Days
• Field of Search: 395/728, 395/821, 395/822, 395/858, 395/860, 395/871, 395/893, 400/472
• US Class Current: 710/2
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes

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.

Claims

1. 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.

2. The system of claim 1, wherein data inputted to said keyboard microcontroller is stored during said hold state.

3. The system of claim 1, wherein said wedge microcontroller sends a signal via said switch control connection to open said switching device when said wedge microcontroller has data to be transmitted to said personal computer microcontroller.

4. The system of claim 1, wherein said wedge microcontroller monitors said clock and data lines to determine whether data is being transmitted from said keyboard microcontroller to said personal computer microcontroller without affecting the direct connection between said keyboard and personal computer microcontrollers.

5. The system of claim 1, wherein opening of said switching device and preventing said keyboard microcontroller from transmitting data to said personal computer microcontroller occur substantially simultaneously.

6. The system of claim 1, wherein said personal computer microcontroller and said keyboard microcontroller function without regard to said wedge microcontroller when said switching device is closed.

7. The system of claim 1, wherein said personal computer microcontroller and said keyboard microcontroller remain directly connected unless said switching device is opened.

8. The system of claim 1, wherein said switching device is utilized to dynamically disconnect and reconnect said personal computer microcontroller and said keyboard microcontroller.

9. The system of claim 4, wherein said wedge microcontroller sends a signal via said switch control connection to open said switching device when said clock and data lines between said keyboard microcontroller and said personal computer microcontroller are determined to be idle.

10. The system of claim 3, wherein said wedge microcontroller sends a signal via said switch control connection to close said switching device upon completion of data transmission from said wedge microcontroller to said personal computer microcontroller so that said keyboard microcontroller and said personal computer microcontroller are reconnected.

11. The system of claim 3, wherein opening of said switching device and transmission of data from said wedge microcontroller to said personal computer microcontroller occur substantially simultaneously.

12. A method of periodically connecting a wedge microcontroller to a personal computer microcontroller for data transmission, wherein said personal computer microcontroller is directly connected to a keyboard microcontroller by means of a clock line and a data line, said method comprising the following steps:

(a) providing a switching device in the clock and data lines connecting said personal computer microcontroller and said keyboard microcontroller;

(b) providing said wedge microcontroller with a first set of connections to said clock and data lines at a location between said switching device and said keyboard microcontroller;

(c) providing said wedge microcontroller with a second set of connections to said clock and data lines at a location between said switching device and said personal computer microcontroller;

(d) permitting said wedge microcontroller to control the opening and closing of said switching device so that said direct connection between said keyboard microcontroller and said personal computer microcontroller may be disabled when said wedge microcontroller has data to be transmitted 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.

13. 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.

14. The method of claim 13, wherein opening of said switching device and transmission of data from said wedge microcontroller to said personal computer microcontroller occur substantially simultaneously.

15. The method of claim 13, further comprising the step of closing said switching device when said wedge microcontroller has completed transmission of data to said personal computer microcontroller.

16. The method of claim 13, further comprising the step of storing data inputted to said keyboard microcontroller when said switching device is open.

17. The method of claim 16, further comprising the step of transmitting said stored data from said keyboard microcontroller directly to said personal computer microcontroller after said switching device is reclosed.