Controllerless modem

• US 6,799,225 B2
• Filed: 02/06/2001
• Issued: 09/28/2004
• Est. Priority Date: 01/31/1996
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Dykes, Don A., Eyres, Kevin W., Brown, Peter J., Love, Andrew L., Sands, G. Byron
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): NGUYEN, TANH Q
• Application Number:
  US09/778,511
• Publication Number:
  US 20010037414A1
• Time in Patent Office: 1,330 Days
• Field of Search: 710/1, 710/5, 710/8, 710/21, 710/62-64, 710/71-73, 710/100, 710/106, 703/13, 703/21-26, 709/321, 709/324, 709/327, 375/220, 375/222, 379/93.05
• US Class Current: 710/5
• CPC Class Codes: G06F 13/105 where the programme performs an input/output emulation function

Abstract

A computer system implements a standard modem without the use of a microcontroller. Instead, a digital signal processor is provided on an expansion card, but with direct links to the computer system itself. The code usually implemented in the microcontroller is instead implemented as a virtual modem controller to be called by the operating system of the computer itself. Further, this virtual modem controller includes a virtualized UART, that appears to the operating system software as a hardware UART, with entry points for calls to replace input/output instructions. In this way, standard device driver code written to execute input/output operations is easily converted to operate with the “virtualized” UART.

Claims

1. A general purpose computer system for use with a modem that lacks a microcontroller for executing a modem controller code, where the general purpose computer system executes the modem controller code, comprising:

a processor for executing instructions;

a virtualized UART interface for execution by said processor, said virtualized UART interface communicating data to and from the modem controller code;

an input/output bus coupled to said processor, said input/output bus adapted to communicate with a controllerless hardware modem; and

wherein said processor executes both general computer system code and the modem controller code and communicates data and commands between the executed modem controller code and the controllerless hardware modem,

an operating system,

wherein the virtualized UART interface appears to the operating system to be a physical UART.

2. The computer system of claim 1, further comprising:

a device driver for the physical UART, said device driver called by said operating system to perform serial operations with the physical UART; and

wherein said virtualized UART interface provides entry points corresponding to reads from and writes to the physical UART;

wherein said device driver is modified to call said entry points to perform reads from and writes to said virtualized UART interface in place of the physical UART.

3. The computer system of claim 2, wherein said virtualized UART interface emulates a 16450 UART.

4. The computer system of claim 2, wherein said device driver is a WINDOWS®

3.1 virtual device driver.

5. The computer system of claim 2, wherein said device driver is a Windows®

95 virtual device driver.

6. The computer system of claim 2, wherein said processor is an x86 series processor, and wherein the virtual device driver is modified by replacing “

IN AL,DX” and

“

OUT DX,AL”

instructions with calls to entry points.

7. The computer system of claim 2, wherein said virtualized UART interface provides a compartmentalized interface to said device driver such that said operating system can be changed to a second operating system with a second device driver without significant modification to said virtualized UART interface.

8. The computer system of claim 2, wherein said virtualized UART interface provides a compartmentalized interface to said device driver such that said controllerless hardware modem can be changed to a second controllerless hardware modem without significant modification to said device driver.

28. The general purpose computer system of claim 1, further comprising:

an operating system device driver,

the virtualized UART interface to simulate a hardware UART interrupt to the operating system device driver.

29. The general purpose computer system of claim 1, the virtualized UART interface to perform UART functions.

9. A computer system for use with a modem lacking a microcontroller for executing modem controller code, comprising:

a processor for executing instructions, said processor executing the modem controller code;

a virtualized version of a physical hardware interface, said virtualized version executable by the processor to provide a virtualized interface to the executing modem controller code; and

a device driver written to communicate with a physical hardware interface, wherein said device driver is modified by replacing instructions directed to the physical hardware interface with calls to said virtualized interface,

wherein the physical hardware interface comprises a UART.

10. The computer system of claim 9, wherein said virtualized interface is a virtualized 16450 compatible interface.

11. The computer system of claim 9 wherein said device driver is a WINDOWS®

3.1 virtual device driver.

12. The computer system of claim 9, wherein said device driver is a WINDOWS®

95 virtual device driver.

30. The computer system of claim 9, wherein the virtualized version of the physical hardware interface emulates the physical hardware interface.

32. The computer system of claim 9, further comprising an operating system device driver,

the virtualized version of the physical hardware interface to simulate a hardware interrupt to the operating system device driver by issuing a software interrupt.

13. In a general purpose computer system, a method of providing modem communication without a hardware modem controller, the method comprising:

executing on the general purpose computer system modem controller code for communication with a controllerless hardware modem;

providing a hardware interface for communication from the modem controller code to the controllerless hardware modem; and

providing a virtualized version of a hardware interface between operating system device driver software on the general purpose computer system and the modem controller code executing on the general purpose computer system, the virtualized version of the hardware interface to emulate the hardware interface, whereby modem commands and data are transmitted between the operating system device driver software and the modem controller code,

wherein the hardware interface comprises a UART.

14. A general purpose computer system for use with a modem that lacks a microcontroller for executing a modem controller code, where the general purpose computer system executes the modem controller code, the system comprising:

a processor for executing instructions;

a virtualized UART interface for execution by said processor, said virtualized UART interface communicating data to and from the modem controller code, the virtualized UART interface to emulate a physical UART interface;

a disk drive coupled to said processor for storing the modem controller code;

main memory for storing the modem controller code;

an input/output bus coupled to said processor, said input/output bus adapted to communicate with a controllerless hardware modem; and

wherein said processor executes both general computer system code and the modem controller code and communicates data and commands between said executed modem controller code and the controllerless hardware modem.

15. The computer system of claim 14, further comprising:

an operating system for execution by said processor, said operating system stored on said disk drive and in said memory;

a device driver for a hardware UART device, said device driver called by said operating system to perform serial operations with the hardware UART device, said device driver stored on said disk drive and in said main memory; and

wherein said virtualized UART interface provides entry points corresponding to reads from and writes to the hardware UART device, said virtualized UART interface stored on said disk drive and in said main memory;

wherein said device driver is modified to call said entry points to perform reads from and writes to said virtualized UART interface in place of the hardware UART device.

16. A method for providing modem communications in a general purpose communication system, the method comprising:

executing a virtualized UART interface on a processor of the system adapted to execute general purpose computer system codes, wherein the virtualized UART interface emulates a UART;

executing a modem controller code on the processor;

communicating modem commands and data between the virtualized UART interface and the modem controller code;

providing a modem without a controller for communicating over a telecommunications link; and

transmitting data and commands between the modem and the modem controller code.

17. The method of claim 16, further comprising:

modifying a standard operating system device driver to call the virtualized UART interface.

18. The method of claim 17, wherein modifying a standard operating system device driver comprising the step of:

replacing input/output instructions of the processor with calls to the virtualized UART interface.

19. The method of claim 16, wherein executing a virtualized UART interface comprises:

simulating a hardware UART interrupt to an operating system device driver entry point from the virtual UART interface.

20. A general purpose computer system with a modem that lacks a hardware microcontroller, the general purpose computer system comprising:

a processor for executing instructions;

means for controlling the modem;

means for virtualizing a hardware UART;

means for communicating standard modem commands and data between an operating system and the means for virtualizing a hardware UART;

means for communicating standard commands and data between the means for virtualizing a hardware UART and the means for controlling the modem; and

means for transmitting data and commands between the means for controlling the modem and the modem.

21. The general purpose computer system of claim 20, the means for communicating between the operating system and the means for virtualizing a hardware UART comprising:

means for replacing input/output instructions of a standard operating system device driver with calls to the means for virtualizing a hardware UART.

22. The general purpose computer system of claim 20, the means for communicating between the operating system and the means for virtualizing a hardware UART comprising:

means for generating software interrupts by the means for virtualizing a hardware UART.

23. A system comprising:

a controllerless modem;

a software module to emulate a hardware serial interface;

modem controller code; and

a device driver to access the software module instead of the hardware serial interface,

wherein the modem controller code is executable to communicate data with the controllerless modem,

wherein the software module is adapted to emulate a UART.

24. The system of claim 23, wherein the controllerless modem contains a digital signal processor.

25. The system of claim 23, further comprising a processor and general purpose computer code executable on the processor, wherein the modem controller code and the software module are executable on the processor.

26. The system of claim 23, wherein the software module provides entry points corresponding to reads from and writes to the hardware serial interface.

27. The system of claim 26, further comprising an operating system, the device driver to be called by the operating system to perform operations with the hardware serial interface,

wherein the device driver is adapted to call the entry points provided by the software module in response to the call from the operating system.

33. The method of claim 23, further comprising:

accessing the virtualized version of the hardware interface identically as if the virtualized version is a real hardware interface.

34. The method of claim 23,

the virtualized version of the UART performing UART functions.

31. A computer system for use with a modem lacking a microcontroller for executing modem controller code, comprising:

a processor for executing instructions, said processor executing the modem controller code;

a virtualized version of a physical hardware interface, said virtualized version executable by the processor to provide a virtualized interface to the executing modem controller code; and

a device driver written to communicate with a physical hardware interface, wherein said device driver is modified by replacing instructions directed to the physical hardware interface with calls to said virtualized interface,

wherein the virtualized version of the physical hardware interface emulates the physical hardware interface; and

an operating system,

wherein the virtualized version of the physical hardware interface appears to the operating system to be the physical hardware interface.