Patent Publication Number: US-7914325-B2

Title: Connector, printed circuit board, connecting device connecting them, and method of testing electronic part, using them

Description:
RELATED APPLICATIONS 
     This application is a division of U.S. Ser. No. 12/222,553, filed Aug. 12, 2008, now U.S. Pat. No. 7,628,645 which application is a division of U.S. Ser. No. 11/657,463, filed Jan. 25, 2007, now U.S. Pat. No. 7,425,151 which application is a continuation of International Application No. PCT/JP2005/013875, filed Jul. 28, 2005, which application claims priority of Japanese Application No. 2004-219804, filed Jul. 28, 2004, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a connector, a printed circuit board, a connecting device connecting them, and a test device that tests an electronic part, using them. Particularly, the invention relates to a method of testing an electronic part mounted on a printed circuit board, by connecting a connector attached to a test device, to a test region provided on the printed circuit board, and also relates to a connector, a printed circuit board, and a connecting device that connects them capable of properly performing the testing method. 
     BACKGROUND OF ART 
     In testing a printed circuit board, conventionally, plural probes connected to a test device are arranged, in the same pattern as the pattern of electrode pads on the printed circuit board, and are brought into contact with the respective electrode pads. Spring probes are used as testing probes. The spring probes are arranged in a dedicated jig, and are pressed against the electrode pads on the printed circuit board. This method makes it necessary to develop and manufacture jigs in line with printed circuit boards, and the cost of developing and manufacturing a jig arises for each type of printed circuit board. Moreover, the jig that supports the spring probes has a relatively complex structure, and a mechanism for supporting the printed circuit board is also necessary. 
     As a method of connecting a printed circuit board to a test device, a method of mounting a dedicated connector ion the printed circuit board is available. According to this method, a connector mounting design capable of mounting the connector on the printed circuit board is necessary. Consequently, cost of parts of the connector, and labor and expenses for mounting the connector arise. 
     A conventional example of a connector attached to a printed circuit board is disclosed in Japanese Unexamined Patent Publication No. 2002-268911. According to this technique, terminal pins of the connector are inserted into through-holes formed on the printed circuit board. 
     Patent literature 1: Japanese Unexamined Patent Publication No. 2002-268911 
     DISCLOSURE OF INVENTION 
     Problems to be Solved by the Invention 
     It is an object of the present invention to provide a connector that can connect between a test device and a printed circuit board at relatively low cost, a printed circuit board, a connecting device that connects them, and provide a method of testing an electronic part, using them. 
     It is another object of the present invention to provide a connector, a printed circuit board, and a connecting device that connects them, suitable for a unified standard to realize the JTAG test device prescribed in the IEEE 1149.1, for example. 
     Means for Solving the Problems 
     A connector according to the present invention includes plural conducting pins, and at least one fixing pin extending substantially in parallel with the conducting pin. The fixing pin is longer than the conducting pin. 
     The fixing pin has a structure suitable for being fixed to a printed circuit board. For example, the fixing pin has a tapered structure thinner toward the distal end. Alternatively, the fixing pin includes at least one elastically deformable member, and this member has a hook portion. 
     Preferably, at least one fixing pin is structured to restrict a direction of mounting the connector. Moreover, the at least one fixing pin preferably includes two fixing pins. 
     According to the foregoing structure, the fixing pin of the connector is inserted into a fixing hole formed on a printed circuit board. When the connector is pushed against the printed circuit board, the conducting pins of the connector are brought into contact with electrode pads on the printed circuit board. The fixing pins of the connector are engaged with the fixing holes formed in the printed circuit board when being inserted into the fixing holes. Consequently, the connector is electrically connected to the printed circuit board, and is joined to the printed circuit board. In other words, the connector can be autonomously joined to the printed circuit board. Accordingly, the connector can be easily attached to the printed circuit board, and electrically connected to the printed circuit, without using other jig. 
     The present invention provides a printed circuit board having a test region that can be connected to a connector having at least one fixing pin and plural conducting pins for a testing signal, wherein, in the test region, there are disposed at least one fixing hole into which the fixing pin can be inserted, and plural signal electrodes that can be brought into contact with the conducting pins. 
     In this case, five signal electrodes are disposed at each apex of a square and at a center position of diagonal lines of the square, respectively. Particularly, the five signal electrodes are electrodes for JTAG testing signals. A signal electrode of TCK is disposed at a center position of the diagonal lines of the square. A signal electrode of TDI and a signal electrode of TDO are disposed at both ends of one diagonal line, respectively of the square. A signal line of TMS and a signal line of TRST are disposed at both ends of the other diagonal line, respectively of the square. When these signal electrodes are disposed in this way, the arrangement of wiring on the printed circuit board connected to these electrodes can be optimized. 
     Two grounding electrodes are further disposed in the test region, one grounding electrode being disposed at a center position of a first side of the square, and the other grounding electrode being disposed at a center position of a third side of the square opposite to the first side. The signal electrodes or the grounding electrodes are electrode pads. 
     Two fixing holes are disposed on a straight line between the first side and the third side of the square, at positions separated from the center positions of the diagonal lines in mutually opposite directions, respectively. In this case, when diameters or cross-sectional shapes of the two fixing holes are mutually different, insertion directions of corresponding connectors can be restricted, thereby preventing an erroneous connection. 
     Further, the present invention provides a connector that can be connected to a test region of a printed circuit board on which at least one fixing hole and plural signal electrodes are disposed, wherein the connector includes a connector body, at least one fixing pin that can be inserted into the fixing hole, and plural signal conducting pins that can be contacted to the signal electrodes, the at least one fixing pin and the plural signal conducting pins being protruded in parallel with each other from the connector body. 
     In this case, five signal conducting pins are disposed at each apex of a square and at a center position of diagonal lines of the square, respectively. Particularly, the five signal conducting pins are pins for the JTAG testing signals. A signal conducting pin of TCK is disposed at a center position of the diagonal lines of the square. A signal conducting pin of TDI and a signal conducting pin of TDO are disposed at both ends of one diagonal line, respectively of the square. A signal conducting pin of TMS and a signal conducting pin of TRST are disposed at both ends of the other diagonal line, respectively of the square. 
     Further two grounding conducting pins are protruded in parallel with the signal conducting pins, from the connector body, and the grounding conducting pins are disposed at a center position of the first side of the square, and at a center position of the third side of the square opposite to the first side, respectively. In this case, when the signal conducting pins or the grounding conducting pins are spring pins, these pins can be retractably attached to the connector body with a spring. 
     Two fixing pins are disposed on a straight line between the first side and the third side of the square, at positions separated from the center positions of the diagonal lines in mutually opposite directions, respectively. In this case, diameters or cross-sectional shapes of the two fixing pins are mutually different. Particularly, it is preferable that one of the two fixing pins has a smaller diameter and a larger length than the diameter and the length, respectively of the other fixing pin. 
     Further, the present invention provides a connecting device including: a connector having a connector body, and at least one fixing pin and plural conducting pins that are protruded in parallel with each other from the connector body; a printed circuit board having at least one fixing hole into which the fixing pin can be inserted, and a test region in which plural electrodes that can be contacted to the conducting pins are disposed; and a mechanism for positioning and fixing the connector to the printed circuit board to keep the conducting pins contacted to the electrodes in a state that the fixing pins are inserted into the fixing holes. 
     In this case, the conducting pins provided in the connector include five signal conducting pins that are disposed at each apex of a square and at a center position of diagonal lines of the square, respectively, and the electrodes provided on the printed circuit board include five signal electrodes disposed at each apex of a square and at a center position of diagonal lines of the square, respectively, the five signal conducting pins being able to be brought into contact with the five signal electrodes, respectively. Particularly, the five sets of the signal conducting pins and the electrodes provided on the connector and the printed circuit board, respectively are sets of pins and electrodes for the JTAG testing signals. Each set of a signal conducting pin and a signal electrode are: TCK disposed at the center position of the diagonal lines of the square; TDI disposed at one end of one diagonal line; TDO disposed at the other end of the one diagonal line; TMS disposed at one end of the other diagonal line; and TRST disposed at the other end of the other diagonal line. 
     The connector further has two grounding conducting pins that are protruded in parallel with the signal conducting pins, from the connector body, and the printed circuit board further has grounding electrodes that can be contacted to the two grounding conducting pins. These two sets of grounding conducting pins and electrodes are disposed at the center position of the first side of the square and at the center position of the third side of the square opposite to the first side, respectively. 
     Both or either one of the signal electrode and the grounding electrode is an electrode pad, and both or either one of the signal conducting pin and the grounding conducting pin is a spring pin retractably attached to the connector body with a spring. These conducting pins are pushed against the electrode pads with spring force. The connector has two fixing pins that are protruded in parallel with the signal conducting pins, from the connector body, and the printed circuit board has two fixing holes into which the fixing pins can be inserted. These two sets of fixing pins and fixing holes are disposed on a straight line between the first side and the third side of the square, at positions separated from the TCK signal conducting pin in mutually opposite directions. 
     Diameters or cross-sectional shapes of the two sets of fixing pins and fixing holes are mutually different. 
     Further, the present invention provides a method of testing an electronic part mounted on a printed circuit board, the method including inserting a fixing pin of a connector into a fixing hole provided in a test region on the printed circuit board, bringing plural conducting pins of the connector into contact with plural electrodes, respectively that are electrically connected to the electronic part and are disposed in the test region, and positioning and fixing the connector to the printed circuit board so as to maintain a contact state between the conducting pins and the electrodes. 
     Five signal conducting pins that are provided in the connector and are disposed at each apex of a square and at a center position of diagonal lines of the square, respectively are brought into contact with five signal electrodes, respectively that are provided in the test region on the printed circuit board and are disposed at each apex of a square and at a center position of diagonal lines of the square, respectively. Particularly, the five sets of signal conducting pins and electrodes provided on the connector and the printed circuit board, respectively are sets of pins and electrodes for the JTAG testing signals. Each set of a signal conducting pin and a signal electrode are TCK disposed at the center position of the diagonal lines of the square; on the other hand, TDI disposed at one end of one diagonal line, and TDO disposed at the other end of the one diagonal line; TMS disposed at one end of the other diagonal line, and TRST disposed at the other end of the other diagonal line. These pairs of pins and electrodes are brought into contact with each other. 
     The connector further has two grounding conducting pins, and the printed circuit board further has grounding electrodes that can be contacted to the two grounding conducting pins. These two sets of grounding conducting pins and electrodes are disposed at the center position of the first side of the square and at the center position of the third side of the square opposite to the first side, respectively. At the time of connecting the connector, these pairs of grounding conducting pins and electrodes are simultaneously brought into contact with the corresponding pairs of signal conducting pins and electrodes, respectively. In this case, both or either one of the signal electrode and the grounding electrode is an electrode pad, and both or either one of the signal conducting pin and the grounding conducting pin is a spring pin retractable with a spring. At the time of connecting the connector, both or either one of the signal conducting pin and the grounding conducting pin is pressed against the electrode pad with spring force. 
     The connector has two fixing pins. A distal end of at least one of the two fixing pins is tapered, and has a hook portion. The printed circuit board has two fixing holes into which the fixing pins can be inserted. At least one of the two fixing holes is a through-hole. At the time of connecting the connector, the hook portion of the fixing pin is locked with the back side of the through-hole, thereby positioning and fixing the connector to the printed circuit board. 
     The connector has two fixing pins, and the printed circuit board has two fixing holes into which the fixing pins can be inserted. Diameters or cross-sectional shapes of the two sets of fixing pins and fixing holes are mutually different, thereby restricting a direction of connecting the connector to the printed circuit board. Particularly, one of the two fixing pins has a smaller diameter and a larger length than the diameter and the length, respectively of the other fixing pin. The one of the pins is inserted into the corresponding fixing hole, and the other fixing pin is inserted into the corresponding fixing hole. 
     EFFECT OF THE INVENTION 
     According to the present invention, a connector can be electrically connected to a printed circuit board relatively easily and securely, by bringing a conducting pin at the connector side into contact with an electrode at the printed circuit board side. Further, based on the engagement between a fixing pin and a fixing hole, a state that the conducting pin is electrically connected to the electrode can be secured. When the connector is connected to a test device, an electronic part mounted on the printed circuit board can be tested, by connecting the test device to the printed circuit board at relatively low cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view showing an example in which a connector according to an embodiment of the present invention is connected to a printed circuit board and a test device; 
         FIG. 2  is a view showing a region in which plural electrode pads and plural fixing holes are arranged on a part of the printed circuit board shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of the connector; 
         FIG. 4  is a bottom view of the connector shown in  FIG. 3 ; 
         FIG. 5  is a perspective view of the connector showing an initial state of attachment of the connector to the printed circuit board; 
         FIG. 6  is a perspective view of the connector showing a state that the connector is attached to the printed circuit board; 
         FIG. 7  is a view showing an example of a conducting pin formed as a spring probe; 
         FIG. 8  is a view showing an example of a hook portion of a fixing pin; 
         FIG. 9  is a view showing another example of a fixing pin; 
         FIG. 10  is a view showing still another example of a fixing pin and a fixing hole; 
         FIG. 11  is a view showing still another example of the arrangement of plural electrode pads and plural fixing holes; 
         FIG. 12  is a view showing an example of plural fixing holes whose shapes are different from each other; 
         FIG. 13  is a view showing an example of plural fixing holes whose shapes are different from each other; 
         FIG. 14  is a view showing an example of plural fixing holes whose shapes are different from each other; 
         FIG. 15  is a view showing still another example of a layout and shapes of fixing holes; 
         FIG. 16  is a view showing still another example of a layout and shapes of fixing holes; 
         FIG. 17  is a view showing still another example of a shape of a fixing hole; 
         FIG. 18  is a view showing still another example in which lengths, sizes of cross sections, and shapes of two fixing pins, respectively are changed; and 
         FIG. 19  shows an example of a layout of electrode pads suitable for a unified standard to realize the JTAG test. 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS 
     
         
         
           
               10  an attachment structure 
               12  a printed circuit board 
               14  a connector 
               16  a cable 
               18  a test device 
               20  a semiconductor element 
               22  an electrode pad 
               24  a fixing hole 
               26  a connector body 
               28  a conducting pin 
               30  a fixing pin 
               32  a metallic cylindrical member 
               34  a contact member 
               36  a spring 
               38  a conductive film 
           
         
       
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     An embodiment of the present invention is explained below with reference to the drawings.  FIG. 1  is a view showing an example in which a connector according to the embodiment of the present invention is connected to a printed circuit board and a test device.  FIG. 2  is a view showing a test region in which plural electrode pads and plural fixing holes are arranged on a part of the printed circuit board shown in  FIG. 1 . The test region shown in  FIG. 2  is equivalent to a region to which the connector shown in  FIG. 1  is attached. A description is made below, by way of an example, of an electric connection between an object to be tested and a test device, for in-circuit emulation of a printed circuit board. However, the present invention is not limit to such an example. 
     In  FIGS. 1 and 2 , an attached/assembled structure  10  includes a printed circuit board  12 , and a connector  14 . The connector  14  is constructed to be attached to the printed circuit board  12 , and to be detached from the printed circuit board  12 . The connector  14  is connected to a test device  18  by cables  16 . 
     The printed circuit board  12  includes a semiconductor device  20 , at least one electrode pad (land)  22 , and at least one fixing hole  24 . In the illustrated example, plural (for example, five) electrode pads  22  and plural (for example, two) fixing holes  24  are provided. The fixing holes  24  are through-holes. The printed circuit board  12  has internal circuits and external connection terminals that are not shown. The semiconductor element  20  is connected to the electrode pads  22  via the internal circuits. Other electrical components can be mounted on the printed circuit board  12 . 
     The plural electrode pads  22  are provided according to signals prescribed by the IEEE 1149.1 test bus (called a JTAG bus). JTAG (Joint Test Action Group) testing signals include signals TDI, TDO, TMS, TCK, and TRST. TDI is used for a test data input signal, TDO is used for a test data output signal, TMS is used for a test mode select signal, TCK is used for a clock signal, and TRST is used for a reset signal. The electrode pads  22  and the fixing holes  24  are collectively arranged in one region. Preferably, the number of the electrode pads  22  is five or more. Further, a grounding (GND) electrode pad  22  is preferably included. 
     In  FIG. 2 , two fixing holes  24  and seven electrode pads  22  are arranged in three columns and three rows. Regarding a row or a column where the fixing hole  24  is positioned, at least one fixing hole  24  and at least one electrode pad  22  are aligned in one straight line in one region. 
       FIG. 3  is a perspective view of the connector  14 , and  FIG. 4  is a bottom view of the connector shown in  FIG. 3 . The connector  14  includes a connector body  26 , seven conducting pins  28  projecting downward from the bottom of the connector body  26 , and two fixing pins  30  extending substantially in parallel with the conducting pins  28 . The fixing pins  30  are longer than the conducting pins  28 . The conducting pins  28  are brought into contact with the electrode pads  22  on the printed circuit board  12 , and function as probes for testing. Furthermore, the cables  16  shown in  FIG. 1  extend from the top of the connector  14 . The conducting pins  28  are electrically connected to the cables  16 . 
     The seven conducting pins  28  and the two fixing pins  30  are collectively arranged in one region, in a similar manner to that of the seven electrode pads  22  and the two fixing pins  24  shown in  FIG. 2 , at positions corresponding to the electrode pads  22  and the fixing holes  24 , respectively. When the connector  14  is attached to the printed circuit board  12 , the two fixing pins  30  are inserted into the two fixing holes  24 , and the seven conducting pins  28  are brought into contact with the seven electrode pads  22 . The fixing pins  30  are longer than the conducting pins  28 . The fixing pins  30  are inserted into the fixing holes  24  before the conducting pins  28  are contacted to the electrode pads  22 . The fixing pins  30  serve as guides for attaching the connector  14  to the printed circuit board  12 . 
     Each fixing pin  30  has a structure suitable for being fixed to the printed circuit board  12 . Each fixing pin  30  includes at least one elastically deformable member that can be structured to have a hook portion. In the illustrated example, the distal end of each fixing pin  30  has a split structure. The fixing pin  30  is formed with a pair of elongated members  30   a  that are elastically deformable to move toward and away from each other. A gap  30   b  is formed between the pair of the elongated members  30   a . When the elongated members  30  are elastically deformed toward and away from each other, the gap  30   b  gets smaller or larger. Each elongated member  30   a  has a substantially semicircular cross section. Each elongated member  30   a  has an arrowhead-like hook portion  30   c  at a distal end thereof. 
       FIG. 5  is a perspective view of the connector  14  showing an initial state of attachment of the connector  14  to the printed circuit board  12 .  FIG. 6  is a perspective view of the connector  14  showing a state that the connector  14  is attached to the printed circuit board  12 . In attaching the connector  14  to the printed circuit board  12 , the fixing pins  30  of the connector  14  are inserted into the fixing holes  24  on the printed circuit board  12 , and the connector  14  is pressed against the printed circuit board  12 . As a result, the conducting pins  28  of the connector  14  are brought into contact with the electrode pads on the printed circuit board  12 . 
     A distance between the external surfaces of each of the pair of elongated members  30   a  of the fixing pin  30  is larger than the inner diameter of each fixing hole  24  on the printed circuit board  12 . The lower tapered parts of the distal hook portions  30   c  of the pair of elongated members  30   a  are first inserted into the fixing holes  24 , respectively. When each fixing pin  30  is pushed into the fixing hole  24 , the gap  30   b  between the pair of elongated members  30   a  becomes smaller. Once the hook portions  30   c  pass through the lower edge of the fixing hole  24  (i.e., the bottom surface of the printed circuit board  12 ), the pair of elongated members  30   a  are opened. Accordingly, the elongated members  30   a  are brought into contact with the internal surface of the fixing hole  24 , and the hook portions  30   c  are engaged with the lower surface of wall of the printed circuit board  12 . Consequently, the fixing pin  30  is substantially immovably held in the fixing hole  24 . 
     In this state, the conducting pins  28  of the connector  14  are in contact with the electrode pads  22  on the printed circuit board  12 , and the connector  14  is electrically connected to the printed circuit board  12 . Moreover, the connector  14  is mechanically joined to the printed circuit board  12 . Accordingly, the fixing pins  30  serve to secure the electrical contact between the conducting pins  28  and the electrode pads  22 , and maintain the mechanical connection between the connector  14  and the printed circuit board  12 . In other words, the connector  14  is autonomously joined to the printed circuit board  12 . Consequently, the connector  14  can be easily attached to and electrically connected with the printed circuit board  12 , without using any other jig. 
       FIG. 7  is a view showing an example of the conducting pin  28  formed as a spring probe. The conducting pin  28  includes a metallic cylindrical member  32  disposed in the connector body  26 , a contact member  34  movably fitted in the metallic cylindrical member  32 , and a spring  36  interposed between the metallic cylindrical member  32  and the contact member  34 . When the conducting pin  28  is pressed against the electrode pad  22 , the probe  34  is brought into contact with the electrode pad  22  under the force exerted by the spring  36 . Accordingly, the conducting pin  28  can be securely brought into contact with the electrode pad  22 . 
     After the connector  14  is coupled to the printed circuit board  12 , a desired test or the like is carried out. After the test is completed, the connector  14  is detached from the printed circuit board  12 . 
     In order to detach the connector  14  from the printed circuit board  12 , the connector  14  is pulled out of the printed circuit board  12  with certain force. This causes the pair of elongated member  30   a  of the fixing pin  30  to close, and the hook portions  30   c  are disengaged from the lower surface of the printed circuit board  12 . Accordingly, the fixing pins  30  are unlocked, and the connector  14  can be detached from the printed circuit board  12 . 
     In this case, preferably, the hook portions  30   c  of the fixing pins  30  are devised as follows. That is, when the connector is in use, the conducting pins  28   c  are in contact with the electrode pads  22 , and the hook portions  30   c  are locked so as not to come off from the fixing holes  24  due to the spring force exerted by the springs  36 . In detaching the connector  14  from the printed circuit board  12 , the connector  14  is extracted, by applying force, larger than contact pressure between the conducting pins  28  and the electrode pads  22 , to the fixing pins  30 , thereby extracting the hook portions  30   c  from the fixing holes  24 . 
     For example, as shown in  FIG. 8 , a part  30   d  of the hook portions  30   c  of the fixing pin  30 , which is engaged with the lower surface of the printed circuit board  12 , is slightly rounded or tilted relative to a plane parallel with the lower surface of the printed circuit board  12 . 
       FIG. 9  shows another example of the fixing pin  30 . The fixing pin  30  is shaped to be thinner towards the distal end thereof, and be thick in the middle portion. When the fixing pin  30  is inserted into the fixing hole  24 , the fixing pin  30  stops halfway, and friction arises between the fixing pin  30  and the fixing hole  24 . The fixing pin  30  is held immovable in the fixing hole  24  due to the frictional force. Accordingly, when the connector is in use, the fixing pins  30  will not come off from the fixing holes  24  due to the spring force exerted by the springs  36 . In detaching the connector  14  from the printed circuit board  12 , the connector  14  is extracted from the fixing hole  24 , by applying force, larger than contact pressure between the conducting pins  28  and the electrode pads  22 , to the fixing pins  30 . 
     The fixing pins  30  and the fixing holes  24  serve as a guiding mechanism for attaching the connector  14  to the printed circuit board  12 , and realize the mechanical connection between the connector  14  and the printed circuit board  12 . Accordingly, the fixing pins  30  and the fixing holes  24  serve to maintain the electrical contact between the conducting pins  28  and the electrode pads  22 . 
       FIG. 10  shows still another example of the fixing pin  30  and the fixing hole  24 . In this example, the fixing hole  24  is formed as a through-hole for use in attaining electrical connection. In other words, a conductive film  38  is formed on the fixing hole  24 , and the fixing pin  30  is made of a conductive material. Consequently, the fixing pin  30  is electrically connected to the conductive film  38 . In this way, the fixing pin  30  has both the above function of the fixing pin  30  and the function of the conducting pin  28 . 
       FIG. 11  to  FIG. 18  show examples of a structure for restricting a mounting direction of the connector  14 .  FIG. 11  shows still another example of a layout of plural electrode pads  22  and plural fixing holes  24 . While the two fixing holes  24  are arranged symmetrically in a second row in FIG.  2 , the two fixing holes  24  are arranged symmetrically at both ends of a first row, respectively in  FIG. 11 . Accordingly, the two fixing pins  30  are also arranged symmetrically at both ends of the first row, respectively. Alternatively, the two fixing holes  24  can be disposed at both ends of a third row, respectively, or at both ends of a first column or a third column, respectively in a vertical direction. The layout of the two fixing pins  30  can be changed corresponding to this layout. 
       FIG. 12  shows an example of plural fixing holes  24  whose shapes are different from each other. Sizes (diameters) of the two fixing holes  24  are different from each other. Accordingly, sizes of the two fixing pins  30  are changed to correspond to the sizes of the fixing holes  24 . 
       FIG. 13  shows an example of plural fixing holes  24  whose shapes are different from each other. One of the fixing holes  24  is a square, and the other fixing hole  24  is a circle. Accordingly, shapes of the two fixing pins  30  are changed corresponding to the shapes of the fixing holes  24 . 
       FIG. 14  shows an example of plural fixing holes  24  whose shapes are different from each other. The two fixing holes  24  are circles, and have different sizes. Accordingly, shapes of the two fixing pins  30  are changed corresponding to the shapes of the fixing holes  24 . Incidentally, the shapes of the fixing holes  24  and the fixing pins  30  are not limited to circles or squares. 
     By changing the respective shapes of the plural fixing holes  24  and the plural fixing pins  30 , incorrect insertion can be prevented, and the conducting pins  28  can be accurately brought into contact with the corresponding electrode pads  22 . 
       FIG. 15  shows still another example of a layout of the electrode pads  22  and the fixing hole  24 . While the two fixing holes  24  are arranged in  FIG. 2 , one elliptical fixing hole  24  is disposed at the center in  FIG. 15 . Accordingly, one fixing pin  30  is formed elliptically. 
       FIG. 16  shows an example of the fixing hole  24  whose shape is changed. One triangular fixing hole  24  is disposed at the center. Accordingly, one fixing pin  30  is formed triangularly corresponding to this shape. In  FIG. 17 , one fixing hole  24  is shaped in a bullet form. In this case, the fixing pin  30  is shaped in a bullet form accordingly. 
     As explained above, one fixing hole  24  and one fixing pin  30  are used to fix the connector  4  to the printed circuit board  12 . By changing the shapes of the fixing hole  24  and the fixing pin  30 , incorrect insertion can be prevented, and the conducting pins  28  can be accurately brought into contact with the corresponding electrode pads  22 . 
       FIG. 18  shows an example in which lengths, sizes of cross sections, and shapes of two fixing pins  301  and  302  at the connector  14  side, respectively are changed. On the printed circuit board  12 , two fixing holes  24  are formed at both sides of the printed circuit board  12 , like in the example shown in  FIG. 12 , and a cross-sectional diameter of one of the fixing holes  24   a  is set smaller than the cross-sectional diameter of the other fixing hole  24   b.    
     On the other hand, at the connector  14  side, the fixing pin  301  has a larger size and a smaller cross section than the size and the cross section of the fixing pin  302 , respectively. The fixing pin  302   30  has a split structure at a distal end, like the fixing pin shown in  FIG. 8 , and is formed with the pair of elongated members  30   a  that are elastically deformable to move toward and away from each other. The gap  30   b  is formed between the pair of the elongated members  30   a . Each elongated member  30   a  has the arrowhead-like hook portion  30   c  at a distal end thereof. 
     According to this structure, the two fixing pins are not simultaneously inserted into the fixing holes, but the fixing pin  301  having a larger length and a smaller thickness is first inserted into the corresponding fixing hole  24   a . With this fixing hole  24   a  used as a guiding hole, the fixing pin  302  having a smaller length and a larger thickness is inserted into the corresponding fixing hole  24   b . When the hook portion  30   c  of the fixing pin  302  is engaged with the surface at the opposite side of the fixing hole  4   b , the connector  14  is positioned and fixed to the printed circuit board  12 . In this embodiment, the fixing pin  302  is inserted into the corresponding fixing hole  24   b , by using the long and thin fixing pin  301  that can be inserted easily and the corresponding fixing hole  24   a , as guides. Therefore, the connector can be inserted and positioned easily. 
       FIG. 19  shows an example of a layout of the electrode pads  22  suitable for standardizing or unifying the layout of the electrode pads  22  for the five signals TDI, TDO, TMS, TCK, and TRST and the two grounding (GND) electrode pads  22  shown in  FIG. 2  to realize the JTAG test. 
     A test region of the printed circuit board to which the testing connector is to be connected is set as a square region of 5.00 mm times 5.00 mm, for example, and a TCK electrode pad is disposed at the center of this region. A square having 2.54 mm in each side is prescribed around this center position. A TDI electrode pad and a TDO electrode pad are disposed at both ends of one diagonal line, respectively. A TMS electrode pad and a TRST electrode pad are disposed at both ends of the other diagonal line, respectively. One ground (GND) electrode pad is disposed at a center position of a first side (i.e., a first row) of this square, and another ground electrode pad is disposed at a center position of a third side of this square (i.e., a third row) opposite to the first side. Each of these electrode pads  22  has a diameter 0.6 mm. When these electrode pads  22  are disposed in this way, the arrangement of wiring on the printed circuit board connected to the electrode pads  22  can be optimized. 
     The two fixing holes  24  are disposed on a straight line (i.e., a second row) between the first side (i.e., the first row) and the third side (i.e., the third row) of the square of which one side is 2.54 mm, at positions separated by an equal distance 1.50 mm from the center of the straight line in mutually opposite directions, respectively. Each of these fixing holes  24  has a diameter 1.00 mm. 
     As described above, it is ideal that the electrode pads  22  and the fixing holes  24  are laid out symmetrically in a vertical direction and a lateral direction, and this layout is suitable for standardization or unification. It is needless to mention that sizes or layouts of the conducting pins  28  and the fixing pins  30  at the connector  14  side are set corresponding to the sizes and layouts of the electrode pads  22  and the fixing holes  24  at the printed circuit board  12  side. 
     INDUSTRIAL APPLICABILITY 
     As explained above, according to the present invention, a connector and electrode pads corresponding to the connector are disposed; the connector has conducting pins that function as probes, and fixing pins that secure a contact between the conducting pins and electrode pads and that maintain a mechanical coupling. With this arrangement, an additional jig that connects between a printed circuit board and a test device is not necessary. Further, a development expense and a manufacturing expense of such a jig can be decreased. The connector can be autonomously connected to the printed circuit board, thereby achieving a secure electrical connection. Therefore, when the connector is used in a state of being connected to the test device, the printed circuit board (or a semiconductor element mounted on the printed circuit board) can be tested at low cost. In addition to the electrode pad for testing, only fixing holes are provided on the printed circuit board. Therefore, there is substantially no cost increase. Because the fixing holes and the conducting pins are collectively disposed in one region, an additional area is not necessary, and the layout of the conducting pins and the electrode pads has a degree of freedom. Further, because the layout of the conducting pins, the electrode pads, the fixing pins, and the fixing holes is constant, the layout combination is suitable for standardization for the JTACT tests.