Multiple interface input/output port allows communication between the interface bus of the peripheral device and any one of the plurality of different types of interface buses

• US 6,073,201 A
• Filed: 09/03/1998
• Issued: 06/06/2000
• Est. Priority Date: 02/20/1996
• Status: Expired due to Fees

• Current Assignee: Bozak Investments LLC (Intellectual Ventures LLC)
• Original Assignee: Iomega Corporation (Dell Technologies Inc.)
• Inventors: Newman, Jon, Jolley, David Lee, Baker, William Paul, Johnson, Rick L.
• Primary Examiner(s): Sheikh, Ayaz R.
• Assistant Examiner(s): PHAN, RAYMOND NGAN
• Application Number:
  US09/146,576
• Time in Patent Office: 642 Days
• Field of Search: 395/307-309, 395/828, 395/835-836, 395/882, 395/886, 395/889, 395/890, 395/281-283, 395/285, 395/311, 395/500, 395/527
• US Class Current: 710/315
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 13/4068 Electrical coupling

Abstract

A multiple interface input/output port allows communication between an interface bus of a peripheral device and any one of a plurality of different types of interface buses that may be provided in a host computer. An interface bus detection circuit detects which type of interface bus the peripheral device is connected to on the host computer, and communications are then routed through an appropriate interface adapter that enables communication between the interface buses of the peripheral device and host computer. The interface bus detection circuit compares signal levels on selected ones of the lines of the interface bus of the host computer to a reference potential to determine which of the selected lines are grounded. The circuit then identifies the type of interface bus to which it is connected based on the determination of which of the selected lines of the interface bus are grounded.

Claims

1. A peripheral device having apparatus that enables communication between an interface bus of the peripheral device and any one of a plurality of different types of interface buses that may be provided in a second device, each of said different types of interface buses comprising a plurality of lines, said apparatus comprising:

a connector;

an interface bus detection circuit electrically coupled to said connector and operable, upon connection of said connector to an interface bus of said second device, to detect the type of the interface bus to which the connector is connected based upon characteristics of selected lines of each of said plurality of different types of interface buses wherein said selected lines have a purpose other than type identification; and

a plurality of interface adapters each electrically coupled between said connector and the interface bus of the peripheral device, each of said interface adapters being operable to enable communication between the interface bus of said peripheral device and a respective one of said plurality of different types of interface buses that may be provided in said second device, communications between the second device and the peripheral device being routed through one of said interface adapters based upon the detected type of the interface bus to which said connector is connected.

2. The peripheral device of claim 1 further comprising means responsive to said interface bus detection circuit for routing data communicated between the interface bus of the peripheral device and the detected interface bus of the second device through said one interface adapter.

3. The peripheral device of claim 1 wherein the interface bus of the peripheral device comprises a Small Computer Systems Interface (SCSI) bus.

4. The peripheral device of claim 1 wherein said plurality of different types of interface buses that may be provided in said second device comprises at least a parallel port interface bus and a SCSI bus.

5. The peripheral device of claim 1 wherein one of said interface adapters comprises a repeater circuit that is enabled when the interface bus of the peripheral device is of the same type as the detected interface bus of the second device, said repeater circuit operating to redrive signals transmitted between the interface buses of the peripheral device and the second device.

6. The peripheral device of claim 1 wherein each of said plurality of different types of interface buses is characterized in that predetermined ones of the lines of the interface bus are grounded, each of the different types of interface buses having different ones of its lines grounded, and further wherein said interface bus detection circuit comprises:

means for comparing signal levels on selected ones of the lines of the host interface bus to which the connector is connected to a reference potential to determine which of said selected lines is grounded; and

means for indicating the type of said interface bus based on the determination of which of its lines are grounded.

7. The peripheral device of claim 6 wherein said plurality of different types of interface buses comprises a SCSI bus and a parallel port interface bus, and wherein each of said different interface buses comprises at least twenty-five lines numbered consecutively, and further wherein said comparing means comprises four voltage comparators coupled respectively to the lines numbered 14, 16, 19 and 25 of the host interface bus for comparing voltage levels on each of said lines 14, 16, 19 and 25 to a reference potential to determine if said lines are grounded.

8. The peripheral device of claim 7 wherein said indicating means indicates that the host interface bus is a SCSI bus when lines 14 and 16 are determined by said comparators to be grounded, and wherein said indicating means indicates that the host interface bus is a parallel port interface bus when either (i) line 25 is determined to be grounded or (ii) line 19 is determined to be grounded, and at least one of lines 14 and 16 are determined not to be grounded.

9. The peripheral device of claim 6 wherein said plurality of different types of interface buses comprises a SCSI bus and a parallel port interface bus, and wherein each of said different interface buses comprises at least twenty-five lines numbered consecutively, and further wherein said comparing means comprises a voltage comparator coupled to the line numbered 25 of the host interface bus for comparing a voltage level on line 25 to a reference potential to determine if line 25 is grounded.

10. The peripheral device of claim 9 wherein said indicating means indicates that the host interface bus is a SCSI bus when line 25 thereof is determined by said comparator not to be grounded, and indicates that the host interface bus is a parallel port interface bus when line 25 thereof is determined by said comparator to be grounded.

11. The peripheral device of claim 1 further comprising a pass-through bus for enabling communication between a third device and said second device through said peripheral device.

12. The peripheral device of claim 1 further comprising an intermediate bus to which said connector is electrically connected, said interface bus detection circuit and each of said plurality of interface adapters being coupled to said connector via said intermediate bus, said intermediate bus serving as an extension of the interface bus of said second device to which the connector is connected.

20. The peripheral device of claim 1 further comprising a pass-through bus for enabling communication between a third device and said second device through said peripheral device.

21. The peripheral device of claim 1 further comprising an intermediate bus to which said connector is electrically connected, said interface bus detection circuit, said repeater circuit and said PP-SCSI adapter each being coupled to said connector via said intermediate bus, said intermediate bus serving as an extension of the interface bus of said second device when said connector is connected thereto.

13. A peripheral device having a Small Computer System Interface (SCSI) bus for communicating with a second device, and having apparatus for enabling communication between the SCSI bus of the peripheral device and an interface bus of the second device, wherein the interface bus of the second device may comprise either a SCSI bus or a parallel port interface bus, each of which comprises a plurality of lines, said apparatus comprising:

a connector;

an interface bus detection circuit electrically coupled to said connector and operable, upon connection of said connector to an interface bus of said second device, to detect whether the interface bus of the second device comprises a SCSI bus or a parallel port interface bus;

based on known characteristics of selected lines of each of said SCSI and parallel port buses wherein said selected lines have a purpose other than bus type identification;

a Parallel Port-to-SCSI (PP-SCSI) adapter electrically coupled between said connector and the SCSI bus of the peripheral device for enabling communication between the SCSI bus of the peripheral device and the interface bus of the second device when the interface bus of the second device is detected to be a parallel port interface bus; and

a repeater circuit operable to redrive signals transmitted, via said connector, between the SCSI bus of the peripheral device and the interface bus of the second device when the interface bus of the second device is detected to be a SCSI bus.

14. The peripheral device of claim 13 further comprising means responsive to said interface bus detection circuit for routing data communicated between the interface bus of the peripheral device and the interface bus of the second device to which it is connected through one of said PP-SCSI adapter and said repeater circuit.

15. The peripheral device of claim 13 wherein the SCSI and parallel port interface buses of the second device are each characterized in that, for each interface bus, different ones of the lines of the interface bus are grounded, and further wherein said interface bus detection circuit comprises:

means for comparing signal levels on selected ones of the lines of the host interface bus to which the connector is connected to a reference potential to determine which of said selected lines is grounded; and

means for indicating whether said host interface bus is a SCSI bus or a parallel port interface bus based on the determination of which of its lines are grounded.

16. The peripheral device of claim 15 wherein said SCSI and parallel port interface buses each comprises at least twenty-five lines numbered consecutively, and further wherein said comparing means comprises four voltage comparators coupled respectively to the lines numbered 14, 16, 19 and 25 for comparing voltage levels on each of said lines 14, 16, 19 and 25 to a reference potential to determine if said lines are grounded.

17. The peripheral device of claim 16 wherein said indicating means indicates that the host interface bus to which the connector is connected comprises a SCSI bus when lines 14 and 16 are determined by said comparators to be grounded, and wherein said indicating means indicates that the host interface bus comprises a parallel port interface bus when either (i) line 25 of the host interface bus is determined to be grounded or (ii) line 19 is determined to be grounded, and at least one of lines 14 and 16 are determined not to be grounded.

18. The peripheral device of claim 15 wherein said SCSI and parallel port interface buses each comprises at least twenty-five lines numbered consecutively, and further wherein said comparing means comprises a voltage comparator coupled to the line numbered 25 for comparing a voltage level on line 25 to a reference potential to determine if line 25 is grounded.

19. The peripheral device of claim 18 wherein said indicating means indicates that the host interface bus to which the connector is connected comprises a SCSI bus when line 25 thereof is determined by said comparator not to be grounded, and indicates that the host interface bus comprises a parallel port interface bus when line 25 thereof is determined by said comparator to be grounded.

22. A circuit for operating a peripheral device having a plurality of different known types of interface buses, wherein each of said plurality of different known types of interface buses has a corresponding interface adapter and wherein each of said plurality of different known types of interface buses comprises a plurality of lines, the lines of each different type of interface bus having known characteristics that distinguish said each different type of interface bus from the others of said plurality of different types of interface buses, said circuit comprising:

means for comparing characteristics of selected ones of the lines of said interface bus to the known characteristics of those lines for each of said different types of interface buses wherein said selected ones of the lines have a characteristic other than bus type identification;

means for identifying the type of said interface bus based on the comparison of said known characteristics; and

selecting an interface adapter based on the type of said interface bus identified.

23. The circuit of claim 22, wherein each of said plurality of known different types of interface buses is characterized in that predetermined ones of the lines of the interface bus are grounded, each of the different types of interface buses having different combinations of its lines grounded, and wherein said means for comparing characteristics comprises means for comparing signal levels on the selected ones of the lines of said interface bus to a reference potential to determine which of said selected lines are grounded and further wherein said means for identifying indicates the type of said interface bus based on the determination of which of its lines are grounded.

24. The circuit of claim 23 wherein the interface bus comprises twenty-five lines numbered consecutively, and wherein said plurality of different types of interface buses comprises a parallel port interface bus and a SCSI bus, and further wherein said comparing means comprises four voltage comparators coupled respectively to the lines numbered 14, 16, 19 and 25 of the interface for comparing voltage levels on each of said lines 14, 16, 19 and 25 to a reference potential to determine which of said lines is grounded.

25. The circuit of claim 24 wherein said identifying means indicates that the interface bus is a SCSI bus when lines 14 and 16 are determined by said comparing means to be grounded, and wherein said identifying means indicates that the interface bus is a parallel port interface bus when either (I) line 25 is determined to be grounded, or (ii) line 19 is determined to be grounded and at least one of lines 14 and 16 is determined not to be grounded.

26. The circuit of claim 23 wherein the interface bus comprises twenty-five lines numbered consecutively, and wherein said plurality of different types of interface buses comprises a parallel port interface bus and an SCSI bus, and further wherein said comparing means comprises a voltage comparator coupled to the line numbered 25 for comparing a voltage level on line 25 to a reference potential to determine whether line 25 is grounded.

28. The circuit of claim 26 wherein said identifying means indicates that the interface bus is a SCSI bus when line 25 is determined by said comparator not to be grounded, and said identifying means indicates that the interface bus test is a parallel port interface bus when line 25 is determined by said comparator to be grounded.

27. A method of operating a peripheral device having a plurality of different known types of interface buses, wherein each of said plurality of different known types of interface buses has a corresponding interface adapter and wherein each of said plurality of different know types of interface buses comprises a plurality of lines, the lines of each different type of interface bus having known characteristics that distinguish said each different type of interface bus from the others of said plurality of different types of interface buses, said method comprising the steps of:

comparing characteristics of selected ones of the lines of said interface bus to the known characteristics of those lines for each of said different types of interface buses wherein said selected ones of the lines have a characteristic other than bus type identification;

identifying the type of said interface bus based on the comparison of said known characteristics; and

selecting an interface adapter based on the type of said interface bus identified.

29. The method of claim 27, wherein each of said plurality of known types of interface buses is characterized in that predetermined ones of the lines of the interface bus are grounded, each of the different types of interface buses having different combinations of its lines grounded, and wherein said comparing step comprises comparing signal levels on selected ones of the lines of said interface bus to a reference potential to determine which of said selected lines are grounded, and further wherein said identifying step comprises indicating the type of said interface bus based on the determination of which of its lines are grounded.

30. The method of claim 29 wherein the interface bus comprises twenty-five lines numbered consecutively, and wherein said plurality of different types of interface buses comprises a parallel port interface bus and a SCSI bus, and further wherein said comparing step comprises comparing voltage levels on each of lines 14, 16, 19 and 25 of the interface bus to a reference potential to determine which of said lines 14,16, 19 and 25 is grounded.

31. The method of claim 30 wherein said identifying steps comprises indicating that the interface bus is a SCSI bus when lines 14 and 16 are determined to be grounded, and indicating that the interface bus is a parallel port interface bus when either (I) line 25 is determined to be grounded, or (ii) line 19 is determined to be grounded and at least one of lines 14 and 16 is determined not to be grounded.

32. The method of claim 29 wherein the interface bus comprises twenty-five lines numbered consecutively, and wherein said plurality of different types of interface buses comprises a parallel port interface bus and a SCSI bus, and further wherein said comparing step comprises comparing a voltage level on line 25 of the interface bus to a reference potential to determine whether line 25 is grounded.

33. The method of claim 32 wherein said identifying step comprises indicating that the interface bus is a SCSI bus when line 25 is determined not to be grounded, and indicating that the interface bus is a parallel port interface bus when line 25 is determined by said comparator to be grounded.