COMPUTER INTERFACE APPARATUS

Abstract: A computer interface apparatus is selectably connectable to a PC-Card interface or a parallel port interface of a computer system. In the preferred embodiment, selection is achieved simply by the user choosing the correct cable for connecting to the computer. When the correct cable is connected to the apparatus, the cable causes the apparatus to configure itself to operate with either the parallel or PC-Card port as appropriate. In this preferred embodiment, the apparatus provides a connection to an ATAPI mass storage device although any device for the mass storage of data provided with any other interface may be accommodated.

Description: COMPUTER INTERFACE APPARATUS The present invention relates to a computer interface apparatus and in particular to such apparatus connectable between a computer system and a mass storage device. In the last few years, a considerable market has appeared for portable external storage devices. Typically, such a device comprises a mass storage device such as a hard disk, a computer tape drive, a floppy disk drive or a CD ROM drive, a suitable power supply and connection means for connecting the device to a computer system. This type of device is extremely useful for example for backing up data onto a tape, installing software from a CD ROM onto a computer system not normally having a CD ROM drive or for transferring large amounts of data between computer systems such as between an office and a home computer. Furthermore, this type of device is usually easier to install than a so-called internal storage device which at the very least requires the cover to be removed from the computer system and is therefore unsuitable for inexperienced users. Often installation simply requires connection of the device to the computer system and the loading of suitable software drivers onto the computer system from a supplied floppy disk. Usually the software installation is completely automatic. Many of the above described devices connect to a computer system via the parallel port of the system which port is more normally used for connection to a printer. Some of these devices connect instead to a so-called PC-Card port. This type of port is a general purpose interface (most usually found on notebook computers) designed for the connection of peripheral devices such as storage devices, modems and network adapters. It is a standard interface promoted by the Personal Computer Memory Card International Association (PCMCIA). According to the present invention there is provided computer interface apparatus connectable between a computer system and a mass storage device to permit data transfer between the computer system and the storage device, comprising a first port for connection to a computer system, a second port for connection to a mass storage device, and selection means operable to permit the first port to be selectably connected to one of a parallel port and a PC-Card port of a computer system. Hitherto, it has not been possible to use a single prior art device for connection to both types of ports. Since the PC-Card connection is generally faster than that via the parallel port, there is an incentive to use a PC-Card connection wherever possible. Thus, it is not uncommon to purchase both types of prior art devices and their associated connecting cables and software so that the optimum choice may be made depending on the ports available on a computer system. Clearly this is a disadvantage at least in terms of convenience and cost. By arranging for the present invention to be selectably connected to one of a parallel port and a PC-Card port of a computer system, all of the above disadvantages are overcome. Preferably the selection means includes at least one cable connectable to the first port and preferably the internal arrangement of the cable causes change to operation of at least one other part of the apparatus depending on which connector of the at least one cable is connected to the first port. In the preferred embodiment, two cables are supplied both terminating in the same type of connector for connecting to the first port. The other end of each cable has a PC-Card and a 25 pin parallel port connector attached respectively. Thus when a user desires to connect the apparatus to a parallel port, he selects the cable having the parallel port connector at one end and connects the other end to the first port of the apparatus. This automatically causes the selection means to configure the device for parallel port operation. Alternatively, if a user desires to connect the apparatus to a PC-Card port, the other cable is connected to the first port and the apparatus is automatically configured for PC-Card operation. Preferably, the internal arrangement of the at least one cable which causes the said changed operation includes an electrically conductive coupling between at least two pins on at least one connector of the at least one cable. Preferably the second port is an AT Attachment Packet Interface (ATAPI) interface or it may be another interface used for the attachment of mass storage device such as a Small Computer System Interface (SCSI) interface. Thus, conventional mass storage devices may be used with the apparatus since the ATAPI and SCSI interfaces are well known interfaces for the connection of tape drives, CD ROM drives and hard drives, for example. Furthermore, with the provision of a SCSI interface, a user may even connect a device such as a scanner to his or her computer system. These two interface standards are designed for the connection of computer peripherals to computer systems and are promoted by the X3T13 and X3T10 committees of the American National Standards Institute (ANSI) respectively. Typically the apparatus includes a third port connectable to a computer peripheral device which device is arranged to be connectable to a computer system parallel port. This is commonly termed in the art a "pass-through port". The third port in conjunction with the preferred pass-through means operable to pass data and control signals directly between the first and third ports when the selection means is operating to permit connection of the first port to a parallel port of a computer system, permits a device such as a printer or even additional apparatus in accordance with the invention, to be connected to the computer whilst the apparatus is connected to the parallel port of the computer system. The invention also includes according to a second aspect thereof, a cable for connection between a computer system and the apparatus described above. According to a third aspect of the invention, a mass storage device for connection to the computer system comprises a housing containing a mass storage device coupled to the second port of the apparatus described above. The invention will now be described by way of example with reference to the drawings in which: Figure 1 is a schematic diagram of apparatus in accordance with the invention connected to a parallel port of a computer system; Figure 2 is a schematic diagram of apparatus in accordance with the invention connected to a PC-Card port of a computer system; Figure 3 is a block diagram of the apparatus when configured for connection to a parallel port of the computer system; Figure 4 is a block diagram of the apparatus when configured for connection to a PC-Card port of the computer system; Figure 5 shows the internal connections of a cable for connecting the apparatus of Figure 3 to the parallel port of a computer system; and Figure 6 shows the internal connections of a cable for connecting the apparatus of Figure 4 to the PC-Card port of a computer system. With reference to Figures 1 and 2. the general configuration of the apparatus in accordance with the invention can be seen. A printed circuit board assembly (PCBA) 2 is housed in a housing 4 having a first, 44 pin port 6 for connection to a host computer system and a third, 25 pin port 8 for connection to a computer peripheral normally connectable to the parallel port of a computer system. A second internal port 10 is provided for connection to a hard disk 12 having an ATAPI interface. With particular reference to Figure 1. a cable 14 is provided having at one end a 25 pin connector 16 for connection to the parallel port interface of host computer system 18 and a 44 pin connector 20 for connection to the first port 6. With particular reference now to Figure 2. a different cable 22 is provided for connection to a host computer 24 having a PC-Card interface. The cable 22 has a connector 26 which is mechanically identical to connector 20 but wired differently, and a PC-Card 28 for connection to the host computer system 24. Figures 3 and 4 show the internal wiring of the apparatus and the PCBA 2 in greater detail. The PCBA 2 contains an application specific integrated circuit (ASIC) which is the control circuit for the apparatus. The ASIC comprises three major functions, the Low IDE Data Transceiver 32, the Control Bus Driver 30 and the Core Logic 28. With reference to Figure 3, the PCBA 2 is shown connected to the 44 pin connector 20 of the parallel port cable 14. By virtue of the connections between pins 29 and 43 and pins 30 and 44 of this connector respectively, the ASIC is configured for parallel port operation. In this configuration, the core logic 28 and the control bus driver 30 are enabled and the low Integrated Drive Electronics (IDE) data transceiver 32 is disabled. This causes the data paths shown in solid lines in the Figure to be activated. In parallel port mode, there is no connection on the 44 pin connector to the 8 bit high data path 34. Similarly no connections arc made on connector 20 for the 9 bit control path 35 in this mode. The core logic 28 generates the 8 bit high data, the 8 bit low data and 9 bit control signals on paths 36. 38 and 40 respectively which arc required by the ATAPI device. These signals are generated according to the data and control signals received from the host computer via its parallel port along a parallel port path 42. For detailed identification of the signals, the pin connections and signal names for the connectors 16 and 20 are shown in Figure 5. With reference to Figure 4, in PC-Card mode, the cable 22 instead of making the connections between pins 43 and 29 and 44 and 30 respectively, has connections, between pins 43 and 44 and pins 29 and 30. These connections cause the core logic 28 and control bus driver 30 to be disabled and the low IDE data transceiver 32 to be enabled. It will be noted from both Figures 3 and 4 that pin 44 of the 44 pin connector is always connected to a pull-up circuit 44. In the PC-Card configuration, the 8 bit high data, 8 bit low data and 9 bit control data are generated by the PC-Card 28 and are connected directly through to the ATAPI device 12 via paths 34/36, 38 and 40 respectively. The core logic and control bus driver in their disabled states are caused to put their I/O connections into a high impedance mode using tristate buffers. Thus, the signal paths shown in solid lines in Figure 4 are activated. Similarly, the I/O connections of the low IDE data transceiver 32 are put into a high impedance state when the ASIC is in its parallel port mode. Figure 5 shows the pin assignments and signal names for the cable 14 and Figure 6 shows the pin assignments and signal names for the cable 22. The left table of Figure 6 shows the 9 bit control signals and the right table shows the 16 bit data (8 bit low data and 8 bit high data) signals. From an inspection of the assignments on the 44 pin connector, it will be seen that the pins used for the 8 bit low data in the PC-Card mode are the same as those used for the 8 bit data lines in the parallel mode. These are the only signal lines shared between the two cables 14, 22. Conflict is avoided as described above by causing the low IDE data transceiver 32 to enter a high impedance state when appropriate. It will be appreciated from the above, therefore, that no user operation other than to select the correct connecting cable, need be performed to allow connection of the ATAPI device 12 to either a PC-Card or a parallel port. Thus the invention provides a particularly simple and effective solution to the problems stated in the introduction

Claims: CLAIMS 1 . Computer interface apparatus connectable between a computer system and a mass storage device to permit data transfer between the computer system and the storage device, comprising a first port for connection to a computer system, a second port for connection to a mass storage device, and selection means operable to permit the first port to be selectably connected to one of at least two different ports of a computer system. 2. Apparatus according to claim 1, wherein the two different ports are operable to transfer digital data in a parallel format using different control signals, data word sizes or communication protocols. 3. Apparatus according to any preceding claim, wherein the two different ports have differently mechanically configured connectors. 4. Apparatus according to any preceding claim, wherein the two different ports have different pin assignments. 5. Apparatus according to any preceding claim, wherein the selection means includes at least one cable connectable to the first port and wherein the internal arrangement of the cable causes changed operation of at least one other part of the apparatus depending on which connector of the at least one cable i connected to the first port. 6. Apparatus according to claim 5. wherein the internal arrangement of the at least one cable which causes the said changed operation includes an electrically conductive coupling between at least two pins on at least one connector of the at least one cable. 7. Apparatus according to any preceding claim, wherein the second port is an ATAPI interface. 8. Apparatus according to any of claims 1 to 6. wherein the second port is a SCSI interface. 9. Apparatus according to any preceding claim, further including a third port connectable to a computer peripheral device which device is arranged to be connectable to a computer system parallel port. 10. Apparatus according to claim 9, including pass-through means operable to pass data and control signals directly between the first and third ports when the selection means is operating to permit connection of the first port to a parallel port of a computer system. 1 1. Apparatus according to any preceding claim, wherein one of the two different ports is a parallel port. 12. Apparatus according to any preceding claim, wherein one of the two different ports is a PC-Card port. 13. A cable for connection between a computer system and the apparatus of any preceding claim. 14. A mass storage device for connection to a computer system comprising a housing containing a mass storage device coupled to the apparatus of any preceding claim.

Inventors: VENKATESWARAN P K, VENKATESWARAN, P., K.
Applicants: SHUTTLE TECHNOLOGY LIMITED
Application year: 1997
Main classification: G06F13
IPC codes: G06F3, G06F13