Emulator probe

An emulator probe accelerates the efficiency of program debugging work with an emulator. The emulator probe includes an emulator coupling device in which lead terminals are soldered on string-like cut-out sections provided on the sides of a board having the same dimensions as a package molding portion of a microcomputer. As required, the emulator coupling device or a microcomputer is mounted on an IC socket provided on a target board.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a probe for coupling an in-circuit 
emulator which assists program development in a microcomputer or ASIC 
having that function with a circuit board on which the microcomputer or 
the like is to be mounted. 
2. Description of the Prior Art 
FIG. 1 is a perspective view showing a conventional emulator probe together 
with a microcomputer, an IC socket and a circuit board. FIG. 2 is a 
sectional view showing the state in which the conventional emulator probe 
is coupled with a circuit board. Referring to FIGS. 1 and 2, reference 
numeral 1 designates a target board which is a circuit board on which a 
microcomputer is to be mounted, numeral 2 designates foot patterns which 
are printed on the target board 1 and on which a microcomputer is to be 
mounted, numeral 3 designates an LCC socket in which a connector 5 on a 
board for connecting cable 4 or an LCC packaged microcomputer 8 is to be 
mounted, numeral 4 designates a board for connecting cable which is 
electrically connected to an in-circuit emulator 6 and has a connector 5 
which is to be coupled with the LCC socket 3, and numeral 5 designates a 
connector provided on the board for connecting cable 4. 
Reference numeral 6 designates an in-circuit emulator for evaluating 
microcomputer programs, numeral 7 designates a signal transmitting cable 
for coupling the in-circuit emulator 6 with the board for connecting 
cable, numeral 8 designates an LCC packaged microcomputer which is sealed 
in an LCC package which is a ceramic molding, and numeral 9 designates a 
QFP packaged microcomputer which is sealed in a QFP. After program 
evaluation is completed with the in-circuit emulator 6, the QFP packaged 
microcomputer 9 is soldered onto the foot patterns 2 on which the 
microcomputer is to be mounted, so that it is fit to the target board 1. 
Then, the operation of this invention will be described. Generally, in 
program development for the microcomputer, it is necessary to debug 
designed programs. Before the QFP packaged microcomputer 9 is mounted on 
the target board 9, the in-circuit emulator 6 is connected to the board 9 
and used for debugging the designed program. 
It is difficult to configure the shape of the pins provided on the probe of 
the in-circuit emulator 6 so that it matches the shape of the QFP. If such 
a shape is configured, the pins are likely to be damaged, so that the 
maintenance thereof is not easy to achieve. Thus, the shapes of the probes 
of the in-circuit emulators 6 have been configured to be of a shape 
relatively facilitating the maintenance thereof, for example, in such a 
manner that the shapes of the probes match the shapes of the LCC packages. 
Additionally, the in-circuit emulators 6 are often used each time when a 
new program is designed. Therefore, the probe of the in-circuit emulator 6 
are not permitted to be soldered directly to the target board 1. Thus, 
when debugging with the in-circuit emulator 6, the LCC socket 3 is 
soldered onto the target board 1 in order to couple the in-circuit 
emulator 6 with the target board 1. Then, the connector 5 on the board for 
connecting cable 4 connected to the in-circuit emulator 6 is inserted into 
the LCC socket 3 thereby coupling the in-circuit emulator 6 with the 
target board 1. 
After program evaluation is completed with the in-circuit emulator 6, 
further program evaluation is achieved with a microcomputer chip being 
actually mounted. Namely, the board for connecting cable 4 is removed from 
the LCC socket 3. Then, the LCC packaged microcomputer 8 is mounted on the 
LCC socket 3. In this state, the target board 1 is evaluated. 
However, the LCC packaged microcomputer 8 costs much for its production 
because it is a ceramic molding. Therefore, upon mass production of the 
target board 1, instead of the LCC packaged microcomputer 8, the QFP 
packaged microcomputer 9 which costs less than the former is often used. 
Thus, it is necessary to carry out program evaluation with the QFP packaged 
microcomputer 9 being actually mounted on the target board so as to 
coincide with the condition of mass production. That is, program 
evaluation is performed also in the state in which the QFP packaged 
microcomputer 9 is soldered on the target board 1 after the soldered LCC 
socket 3 is removed from the target board 1. 
If bugs or the like are found in a program at this stage, the soldered QFP 
packaged microcomputer 9 is removed from the target board 1 and then the 
LCC socket 3 is soldered onto the target board 1. Then, the program is 
evaluated again with the in-circuit emulator 6. 
Because the connector 5 of the board for connecting cable 4 is inherent of 
the in-circuit emulator, it is usually produced by resin molding. Further, 
it is necessary to develop an LCC packaged microcomputer 8 and LCC socket 
3 which match the shape of the QFP packaged microcomputer 9. Generally, 
the LCC socket 3 is produced by resin molding. Because, in development of 
circuit boards on which microcomputer is to be mounted, the LCC packaged 
microcomputer 8 and the LCC socket 3 which will not be used at mass 
production stage must be prepared, the cost required for the development 
increases. 
If bugs are found in a program at the stage in which the QFP packaged 
microcomputer 9 is mounted on the target board 1, the soldered QFP 
packaged microcomputer 9 is removed from the target board 1 and then the 
LCC socket 3 is soldered again onto the target board 1. After that, 
program evaluation must be performed with the in-circuit emulator 6. 
Consequently, the efficiency of debugging work lowers. Additionally, the 
reliability of the foot patterns 2 for mounting the microcomputer is 
reduced by repeated soldering works. 
SUMMARY OF THE INVENTION 
An object of the present invention is to solve the above-described problems 
and to provide a program development environment in which the necessity of 
use of any resin molding is eliminated to suppress increases of the 
development cost of new circuit board and debugging can be carried out 
without soldering a QFP packaged microcomputer onto a target board. 
An emulator probe according to the present invention contains an emulator 
coupling device in which lead terminals are soldered on string-like 
cut-out sections provided on the sides of a circuit board having the same 
dimensions as the package molding portion of a microcomputer. 
An emulator probe according to another aspect of the present invention 
contains an emulator coupling device in which lead terminals are soldered 
in the through holes formed on the peripheral of the circuit board having 
the same dimensions as the package molding portion of the microcomputer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 3 is a perspective view showing an emulator coupling device according 
to an embodiment of the present invention together with a microcomputer, 
an IC socket and a circuit board. FIG. 4 is an enlarged perspective view 
of the emulator coupling device. Referring to FIGS. 3 and 4, reference 
numeral 11 designates an IC socket which will be soldered onto the foot 
patterns 2 and on which a QFP packaged microcomputer 9 is to be mounted. 
Numeral 12 designates an emulator coupling device which is to be mounted 
onto the IC socket 11 instead of the QFP packaged microcomputer 9 when an 
in-circuit emulator 6 is used. Hereinafter, the emulator coupling device 
will be referred to as a dummy IC. The dummy IC 12 includes a printed 
circuit board 12a, through holes 12b which are semicircular holes formed 
on the sides of the printed circuit board 12a, lead terminals 12c soldered 
on the through holes 12b and relay connectors 13 fit to the printed 
circuit board 12a. The printed circuit board 12a has the same dimensions 
as the package molding portion (portion excluding the lead terminals) of 
the QFP packaged microcomputer 9. The relay connector 13 has terminals 
electrically connected to the through holes 12b of the dummy IC 12. 
Reference numeral 14 designates a board (pod portion) for connecting cable 
7, which is electrically coupled with the in-circuit emulator 6, to the 
dummy IC 12 via connectors 15 which are to be coupled with the relay 
connectors 13. The connectors 15 are fit to the bottom of the board (pod 
portion) 14. 
The operation of this invention will be described. When program evaluation 
is performed, a commercially marketed IC socket 11 which coincides with 
the QFP packaged microcomputer 9 which is used at mass production stage is 
soldered onto the foot patterns 2. For example, if the QFP packaged 
microcomputer 9 is a 20-pin IC, an IC socket which fits to 20 pins is 
soldered thereon. 
Next, the dummy IC 12 which contains the printed circuit board 12a of the 
same dimensions as the package molding portion (portion excluding the lead 
terminals) of the QFP packaged microcomputer 9 is prepared. As shown in 
FIG. 4, the dummy IC 12 includes semi-circular through holes 12b which are 
formed on the sides of the printed circuit board 12a having the same 
dimensions as the package molding portion of the QFP packaged 
microcomputer 9. The printed circuit board 12a has conductor patterns 
formed thereon to electrically connect each terminal of the relay 
connectors 13 to respective corresponding through holes. 
If the shape of the opening of the through holes is semi-circular, they can 
be formed easily by conventional printed circuit board production 
technology. For example, such through holes can be formed by use of a 
drill or the like. That is, if the shape of the through holes 12b is 
semi-circular, string-like cut-out sections can be formed easily. On the 
other hand, the shape of the opening does not have to be half a proper 
circle (50% semi-circle) and is permitted to be of a shape similar to a 
semi-circle, that is a shape of 30%, 50% or 90% of a proper circle. 
Further, the lead terminal 12c is soldered onto each of the through holes. 
The number of the lead terminals 12c are the same as that of the lead 
terminals of the QFP packaged microcomputer 9. The dimensions of that 
portion of the dummy IC 12 formed in the above-described manner excluding 
the lead terminals are the same as the dimensions of the package molding 
portion of the QFP packaged microcomputer 9. Therefore, the dummy IC 12 
can be mounted on the IC socket 11 as in the case of the QFP packaged 
microcomputer 9. 
When program evaluation is carried out with the in-circuit emulator 6, the 
dummy IC 12 is mounted on the IC socket 11 instead of the QFP packaged 
microcomputer 9. As shown in FIG. 4, the relay connectors 13 having 
terminals electrically coupled with the through holes 12b are provided on 
the top surface of the dummy IC 12. The bottom surface of the board for 
connecting cable 14 has connectors 15 which are electrically connected to 
the in-circuit emulator 6 and can be coupled with the relay connectors 13. 
Coupling the relay connectors 13 with the connectors 15 of the board for 
connecting cable 14 makes the in-circuit emulator 6 to be electrically 
coupled with the target board 1. Thus, it is possible to carry out program 
evaluation with the in-circuit emulator 6. 
After program evaluation with the in-circuit emulator 6 is completed, the 
dummy IC 12 is removed from the IC socket 11. Then, the QFP packaged 
microcomputer 9 is mounted on the IC socket 11 and program evaluation is 
carried out with the microcomputer being actually mounted. 
If bugs in a program are found at this stage, the QFP packaged 
microcomputer 9 is removed from the IC socket 11. Then, the dummy IC 12 is 
mounted on the IC socket 11 and program evaluation with the in-circuit 
emulator 6 is carried out. 
As described above, debugging can be performed without soldering the probe 
of the in-circuit emulator 6 and the QFP packaged microcomputer 9 onto the 
target board 1. Consequently, the efficiency of debugging work increases. 
When program evaluation is carried out with the microcomputer being 
actually mounted, the QFP packaged microcomputer 9 is not soldered. Thus, 
it is possible to prevent loss of reliability of the foot patterns 2, due 
to repeated soldering, on which the microcomputer is to be mounted. 
Because resin molding (LCC socket 3 and connector 5 of the board for 
connecting cable 4) does not need to be prepared and further, the general 
IC socket 11, the connector 13 and the connector 15 are available, it is 
possible to suppress the cost required for development of the target board 
and programs. 
Although the probe of the in-circuit emulator which assists program 
development for the microcomputers is described above, it is possible to 
apply this embodiment to the case of probes of in-circuit emulators for 
gate arrays, ASIC or the like. 
Although the semi-circular through holes 12 are formed on the sides of the 
printed circuit board 12a in the above-described embodiment, it is 
permissible to form completely circular through holes 12d on the 
peripheral of the printed circuit board 12a. In this case, because the 
lead terminals 12c can be soldered in the state in which they are inserted 
in the through holes 12d, soldering of the lead terminals 12c onto the 
foot patterns 2 is facilitated. 
As described above, according to this invention, debugging can be carried 
out without soldering the probe of the in-circuit emulator and the 
microcomputer onto the target board, thereby improving the efficiency of 
debugging work. Additionally, it is possible to prevent deterioration of 
the foot patterns on which the microcomputer is to be mounted. Further, 
because resin molding (LCC socket and connector of the board for 
connecting cable) does not have to be prepared, it is possible to suppress 
development cost. 
If the shape of the opening provided on the cut-out section of the dummy IC 
is semi-circular, such cut-out sections can be formed with conventional 
printed circuit board production technology, so that the string-like 
cut-out sections can be formed easily.