Abstract:
A portable computer having two peripheral bays conforming to integrated drive electronics standard interface. A peripheral in one bay is always recognized as a master device and not a slave device. A peripheral in the other bay is recognized as a slave only when the first bay is occupied by a peripheral. This way, the situation never arises where there is a slave device without a master peripheral device. The bays may reside in the portable computer main body or in a docking station. A circuit can sense the presence or the absence of peripherals in the bays to thus prevent the situation of a slave peripheral being present when there is no master device.

Description:
CLAIM OF PRIORITY 
     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from my application entitled PORTABLE COMPUTER AND METHOD FOR SETTING UP MASTER DEVICE AND SLAVE DEVICE FOR PORTABLE COMPUTER filed with the Korean Industrial Property Office on Dec. 19, 2000 and there duly assigned Ser. No. 78573/2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a portable computer and an automatic setting method of master/slave devices for the portable computer. 
     2. Description of the Related Art 
     Chipsets adapted to be mounted to the main board of a portable computer, for example, chipsets by Intel Corporation, support two integrated drive electronics (IDE) channels, that is, a primary channel and a secondary channel. Generally, the primary channel is allocated for a master hard disk drive internally mounted to a portable computer which is set as a Master. The secondary channel is allocated for optional devices to be externally mounted to the portable computer. To this end, the portable computer is provided with secondary mounting units for mounting optional devices as a master device and a slave device, respectively. Such optional devices may include a CD-ROM, a ZIP drive, a DVD-ROM, a CD-RW, and a second hard disk drive. 
     The secondary mounting units of the conventional portable computers are not fixed for such optional devices as a master device and a slave device, respectively. Instead, optional devices mounted to the secondary mounting units are set to master and slave devices, respectively, using cable select pins provided in those optional devices. 
     In this case, however, there is a drawback in that the optional device set to the master device cannot operate as a slave device. In similar, the optional device set to the slave device cannot operate as a master device. Furthermore, where the master device is removed from the conventional portable computer while the slave device remains mounted, the computer cannot recognize the slave device, and therefore, the slave device cannot be used. 
     What is needed is an automatic mechanism for a portable computer that has two mounting units in which the two mounting units receive external devices. If both mounting units are occupied by external devices, the computer system designates the main mounting unit as the master and the sub mounting unit as the slave. Should the external device be removed from the main mounting unit, while an external device remains in the sub mounting unit, the external device in the sub mounting unit is designated automatically as master so that it can be recognized by the computer. The computer is dockable with a docking station and it is possible to have the sub mounting unit and the main mounting unit to reside in the docking station instead of in the computer. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention is to provide a portable computer capable of using optional devices, mounted thereto, irrespective of a master/slave setting condition initially made. 
     It is also an object of the present invention is to provide an automatic setting method of master/slave devices as optional devices mounted to a portable computer, which is capable of allowing each of those optional devices to be used, irrespective of a master/slave setting condition initially made. 
     It is yet another object of the present invention to provide a computer system having a main mounting unit and a sub mounting unit, so that if both are occupied by external devices, the main mounting unit is master and the sub mounting unit is a slave. 
     It is further an object of the present invention to provide a computer system that automatically recognizes the external device in the sub mounting unit as a master device should the external unit of the main mounting unit be removed. 
     It is further an embodiment of the present invention to provide the main mounting unit and the sub mounting unit in a docking station instead of in a body of a computer allowing the external device in the sub mounting unit to be recognized as a master device when the external device in the main mounting unit is removed. 
     In accordance with one aspect of the present invention, these and other objects may be accomplished by the provision of a portable computer having a computer body, a main board mounted to the computer body, main and sub mounting units connected to the main board and adapted to allow external devices according to an IDE standard interface scheme to be mounted thereto, respectively, external devices each adapted to output a signal indicative of whether or not the external device is connected to an associated one of the main and sub mounting units, each of the external devices having a connection means to be coupled to an associated one of the main and sub mounting units; and a control unit for recognizing the external device mounted to the main mounting unit as a master device and the external device mounted to the sub mounting unit as a slave device, respectively, while recognizing the external device mount to the sub mounting unit as a master device under a condition in which there is no external device mounted to the main mounting unit. 
     Preferably, the portable computer further comprises a docking station separated from the computer body while being connected to the main board for a signal exchange with the main board. The control unit and the main and sub mounting units may be provided in the portable computer. In this case, there is an advantage in that the computer body has a reduced volume. Preferably, the connection means has a ground terminal for outputting the signal indicative of whether or not the external device associated therewith is connected to an associated one of the main and sub mounting units. 
     In accordance with another aspect of the present invention, these and other objects may also be achieved by the provision of an automatic setting method of master/slave devices for external devices mounted to a portable computer including a computer body, a pair of mounting units adapted to allow the external devices to be mounted thereto, respectively, each of the external devices having a configuration according to IDE standard interface scheme, and a main board connected with the mounting units, having the steps of setting the mounting units as main and sub mounting units, respectively, determining whether or not the external devices are mounted to the main and sub mounting units, respectively, and recognizing the external device mounted to the main mounting unit as a master device and the external device mounted to the sub mounting unit as a slave device, respectively, while recognizing the external device mount to the sub mounting unit as a master device when it is determined that there is no external device mounted to the main mounting unit. Preferably, the determination of whether or not each of the external devices is mounted to an associated one of the main and sub mounting units is carried out, based on a ground signal generated when the external device is mounted to the associated mounting unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
     FIG. 1 is a perspective view illustrating a portable computer according to the present invention; 
     FIG. 2 is a block diagram illustrating a control circuit of the portable computer according to the first embodiment of the present invention; 
     FIG. 3 is a flow chart illustrating processes for automatically setting up an optional device mounted to a portable computer as a master or slave device, in the portable computer according to the first embodiment of the present invention; 
     FIG. 4 is a table illustrating the signals of the electronic circuit for the first embodiment of the present invention; and 
     FIG. 5 is a table illustrating the signals of the electronic circuit for the second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a perspective view illustrating a portable computer according to the present invention. FIG. 2 is a block diagram illustrating a control circuit of the portable computer according to the present invention. In the first embodiment of the present invention, element  32  of FIG. 2 is an OR gate as illustrated in FIG.  2 . In the second embodiment of the present invention, item  32  would be an AND gate, while the remaining features of FIG. 2 remain the same for the second embodiment. As shown in FIGS. 1 and 2, the portable computer of the present invention includes a computer body  10  mounted with a plurality of hardware units including a main board  20  and an input unit  50 , and an LCD monitor  51  hingeably mounted to the computer body  10  in such a fashion that it is hingeable between its folded state and its developed state. 
     In addition to the main board  20  and input unit  50 , the hardware units included in the computer body  10  may include a casing  52  adapted to surround the main board  20 . The main board  20  is mounted with a RAM (not shown) and a CPU (not shown). The input unit  50  generates a desired output signal in accordance with an external manipulation for the input unit  50 . 
     The main board  20 , to which the RAM and CPU are mounted, is provided with a main mounting unit  21  and a sub mounting unit  22  respectively adapted to mount optional devices  40   a  and  40   b  to be described hereinafter. 
     The main and sub mounting units  21  and  22  of the main board  20  are expansion IDE slots for mounting optional devices according to an IDE standard interface scheme, that is, the optional devices  40   a  and  40   b , respectively. In the case illustrated in FIG. 1, the optional devices  40   a  and  40   b  mounted to the main and sub mounting units  21  and  22  are a CD-ROM and a hard disk driver, respectively. Of course, other devices such as a ZIP drive, a DVD-ROM, and a CD-ROM may be mounted to the main and sub mounting units  21  and  22 . The main and sub mounting units  21  and  22  transmit signals outputted from the optional devices  40   a  and  40   b  to an IDE controller (not shown) of the main board  20 , respectively. 
     The optional devices  40   a  and  40   b , which are mounted to the main and sub mounting units  21  and  22 , are provided with interface boards  41   a  and  41   b  serving as connection means adapted to electrically connect those optional devices  40   a  and  40   b  to the main and sub mounting units  21  and  22 , respectively. 
     In addition to the function of connecting the optional devices  40   a  and  40   b  to the main and sub mounting units  21  and  22 , the interface boards  41   a  and  41   b  have a function to inform a control unit  30  included in the main board  20  of whether or not the optional devices  40   a  and  40   b  are mounted to the main and sub mounting units  21  and  22 , respectively. To this end, the interface boards  41   a  and  41   b  are provided with ground terminals  31   a  and  31   b , respectively. 
     The control unit  30  provided at the main board  20 , responds to electronic circuits and controls optional device  40   a  mounted to the main mounting unit  21 , to be recognized as a master device while allowing the optional device  40   b , mounted to the sub mounting unit  22 , to be recognized as a slave device. Where there is no optional device mounted to the main mounting unit  21 , that is, where the optional device  40   a  is not mounted, the control unit  30  responds to the same electronic circuits that now have different inputs and thus different outputs than before to allow optional device  40   b , mounted to the sub mounting unit  22 , to be recognized as a master device. 
     FIGS. 3 and 4 are dedicated to the first embodiment of the present invention. Turning to FIG. 4 illustrating the first embodiment of the present invention, when the optional devices  40   a  and  40   b  are mounted to the main and sub mounting units  21  and  22 , the ground terminals  31   a  and  31   b  of the interface boards  41   a  and  41   b  transmit low-level signals to an OR gate  32  included in the control unit  30 , respectively. The OR gate  32  sends a signal of a low or high level to a master-in pin included in the control unit  30 , based on the signals from the main and sub mounting units  21  and  22 . 
     The signal from the master-in pin, that is, the signal from the OR gate  32 , is applied to a field effect transistor (FET)  33  included in the control unit  30 . The FET  33  is short-circuited or opened in accordance with the low or high level of the signal from the OR gate  32  applied thereto. Where the FET  33  is short-circuited, a cable select signal CSEL having a low level is transmitted to a CSEL pin  36  provided at the optional device  40   b . On the other hand, where the FET  33  is opened, a cable select signal CSEL having a high level is transmitted to the CSEL pin  36 . In response to the signal CSEL inputted to the CSEL pin  36  of the optional device  40   b , the control unit  30  recognizes the optional device  40   b  as a master or slave device. 
     The procedure for automatically setting an optional device mounted to a portable computer as a master or slave device, using the above mentioned configuration according to the present invention, will be described according to the first embodiment of the present invention as illustrated in FIG.  3 . In a first example, optional devices according to the IDE standard interface scheme, that is, the optional devices  40   a  and  40   b , are mounted to the main and sub mounting units  21  and  22  provided at the main board  20 , respectively. Once the optional devices  40   a  and  40   b  are mounted to the main and sub mounting units  21  and  22 , the ground terminals  31   a  and  31   b  provided at the interface boards  41   a  and  41   b  included in the optional devices  40   a  and  40   b  transmit low-level signals to the OR gate  32  included in the control unit  30 , respectively. 
     As a result, the OR gate  32  applies a low or high-level signal to the master-in pin of the control unit  30 . The FET  33  in this first embodiment is a p-channel FET  33  of the control unit  30  which short-circuits its source to drain (S-D) path when the master-in signal has a low level. On the other hand, when the master-in signal has a high level, the S-D path of the FET  33  is open circuited. 
     In accordance with the procedure of FIG. 3, it is then determined whether or not the optional devices  40   a  and  40   b  are mounted to the main and sub mounting units  21  and  22 , respectively (Steps S 10  and S 20 ). In a state in which both the optional devices  40   a  and  40   b  are mounted, a low-level signal is transmitted to the master-in pin (Step S 30 ). In response to this master-in signal, the S-D path of the FET  33  included in the control unit  30  is short-circuited (Step S 40 ). As a result, a low-level signal is applied to the CSEL pin  36  (Step S 50 ). 
     In the illustrated case, the optional device  40   b  mounted to the sub mounting unit  22  is set to operate as a slave device when it receives a low-level signal. Following step S 50 , accordingly, the control unit  30  transmits the low-level signal to the optional device  40   b  mounted to the sub mounting unit  22 , thereby controlling the optional device  40   b  to operate as a slave device (Step S 60 ). 
     According to the first embodiment of the present invention illustrated in FIGS. 3 and 4, the ground terminals  31   a  and  31   b  of the interface boards  41   a  and  41   b  transmit low-level signals to an OR gate  31  when the optional devices  40   a  and  40   b  are mounted to the main and sub mounting units  21  and  22  and transmit high-level signals when the optional devices  40   a  and  40   b  are not mounted to the main and sub mounting units  21  and  22 . In a second example of the first embodiment of the present invention, it is determined in step S 10  that optional device  40   b  is mounted to the sub mounting unit  22 , and that where it is determined in step S 20  that the optional device  40   a  is not mounted to the main mounting unit  21 . In regard to step  21  of such a scenario, since the optional device  40   a  is not mounted to the main mounting unit  21  but optional device  40   b  is mounted to the sub mounting unit  22 , the main mounting unit transmits a high-level signal and the sub mounting unit transmits a low-level signal. These signals are transmitted to the OR gate  32  which outputs a high-level signal because the OR gate transmits a high-level signal when at least one signal of both signals is a high-level signal. Accordingly, the OR gate  32  outputs a high-level signal, as a master-in signal, to the master-in pin (Step S 21 ). 
     In response to the master-in signal, the S-D path of the FET  33  is opened (Step S 22 ), so that a high-level signal is applied to the CSEL pin  36  of the optional device  40   b  mounted to the sub mounting unit  22  (Step S 23 ). As a result, the optional device  40   b  is recognized as a master device (Step S 24 ). 
     In a third example of the first embodiment of the present invention illustrated by FIGS. 3 and 4, where it is determined at step S 10  that the optional device  40   b  is not mounted to the sub mounting unit  22 , a high-level signal is transmitted to the master-in pin of the control unit  30  (Step S 15 ). Accordingly, the S-D path of the FET  33  is open circuited (Step S 18 ). Thus, there is no power consumption by the FET where neither the optional device  40   a  nor the optional device  40   b  is mounted or where the optional device  40   a  is mounted to the main mounting unit  21  and the optional device  40   b  is not mounted to the sub mounting unit  22 . 
     Generally, a CSEL pin such as the CSEL pin  36  is provided at an optional device such as the optional device  40   a  or  40   b , in order to allow a setting of the optional device as a master or slave device. Typically, the setting of the optional device  40   a  or  40   b  is carried out in such a fashion that it is recognized as a master device when the signal inputted to the CSEL pin  36  has a high level while being recognized as a slave device when the signal has a low level. In a second embodiment of the present invention as illustrated in FIG. 5, the optional device  40   a  or  40   b  may be set in a manner reverse to that of the previous embodiment so that it is recognized as a master device when the signal inputted to the CSEL pin  36  has a low level while being recognized as a slave device when the signal has a high level. In this second embodiment, the interface boards  41   a  and  41   b  should be appropriately designed in order to change the signals to be inputted to the CSEL pin  36 . This requires ground terminals  31   a  and  31   b  to send a high signal to a logic gate  32  in the main board  20  if an external device  40   a  or  40   b  are inserted into respective mounting units. In addition, in this second embodiment, logic gate  32  must be an AND gate to provide a high signal on a CSEL pin  36  when external device  40   b  is a slave device and a low signal on CSEL pin  36  when external device  40   b  is a master device. In the second embodiment as illustrated in FIG. 5, the FET  33  is a p-channel FET. 
     Although the control unit  30 , main mounting unit  21  and sub mounting unit  22  have been described as being provided at the main board  20 , they may be installed at a docking station (not shown) operatively connected to the portable computer. In this case, of course, the objects of the present invention can be accomplished. 
     Also, the control unit  30  has been described as including an OR or an AND gate  32 , ground terminals  31   a  and  31   b , and FET  33  for a configuration adapted to enable a recognition for optional devices respectively mounted to the main and sub mounting units  21  and  22 , that is, the optional devices  40   a  and  40   b . For this configuration, various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. For instance, the OR gate may be replaced by an AND gate as disclosed in the second embodiment illustrated in FIG.  5 . Other embodiments may include using an n-channel FET instead of a p-channel FET as used in the first two embodiments of the present invention. 
     As apparent from the above description, the present invention provides a portable computer including main and sub mounting units connected to a main board, and a control unit for conducting a control allowing optional devices, mounted to the mounting units, to be used irrespective of a master/slave setting condition initially made. 
     Also, the present invention provides an automatic master/slave setting method for optional devices mounted to a portable computer, which is capable of allowing each of the optional devices to be used irrespective of the master/slave setting condition initially made. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.