JPH098420A - Printed board and printed board - Google Patents

Abstract

(57) [Summary] [Object] The present invention has a plurality of circuit blocks continuously mounted in the order of priority, and a signal propagating between the mounted circuit blocks in the order of priority is mounted on the circuit block. Regardless of the number of printed circuit boards that are output from the same terminal on the printed circuit board, multiple printed circuit boards can be designed using the same printed circuit board, reducing the design period, design cost, drawing maintenance cost, management cost. The purpose is to reduce. [Configuration] A switching circuit that aggregates the output signals of the circuit blocks, selects and outputs the output signal of the circuit block with the lowest priority among the mounted ones, and configures whether or not the circuit block is mounted and the switching circuit A plurality of printed boards are designed using the same printed circuit board by correlating the presence / absence of the component and switching the signal passing through the switching circuit depending on the presence / absence of the component.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed board and a printed board made of the same printed board by selecting a combination of circuit blocks actually mounted within a preset range. As the scale of integrated circuits increases, the degree of integration of the circuits mounted on the printed circuit board increases, the function of the printed circuit board becomes complicated, and the design period becomes longer. Since it is designed, the design cost has become huge. Further, the diversification of printed boards has led to an increase in the number of boards for printed boards, and the costs required for parts management and the costs required for maintaining drawings have become enormous. For this reason, a circuit block that has a large-scale integrated circuit, such as a general-purpose processor and a processor dedicated to floating-point arithmetic, has a scan path for diagnosis, and has a predetermined mounting sequence on the printed circuit board. The printed boards to be constructed need to be designed using the same printed board regardless of the number of circuit blocks mounted.

2. Description of the Related Art For example, in a device having a scan path for diagnosis, scan data input from an input terminal of a printed board propagates through a circuit block in the printed board and is output from an output terminal to output the next print. In order to input to the board, the input terminal and the output terminal of the scan at the fixed mounting position of the printed board are fixed. In the conventional method, a general-purpose processor is basically mounted and a floating-point arithmetic processor is optionally mounted, so that it is mounted exclusively at the same position, and it is consecutive from the highest to the lowest in order of predetermined priority. Then, a plurality of circuit blocks are connected to each other, and signals are sequentially propagated from higher priority to lower priority, and the printed board output from the fixed terminal of the printed board is as shown in FIGS. 6 and 7. In addition, each of the combinations of circuit blocks to be mounted was designed by using different printed circuit boards in which the input / output terminals were aligned at the same position. That is, in the conventional printed circuit board provided with the optional function, a new printed circuit board must be designed and developed in order to add / delete the optional function.

Therefore, since various kinds of printed boards having a high degree of integration are designed, the design period becomes long, the design cost becomes enormous, and the number of parts to be managed increases. However, there has been a problem that the maintenance cost of the device and the management cost of the printed circuit board become large. According to the present invention, the mounting order is determined in advance, and the circuit blocks are sequentially mounted according to the order, and the signals are sequentially propagated from the higher priority to the lower priority in the order of the priority to be mounted. An object of the present invention is to provide a printed board that is output from a fixed terminal of the printed board regardless of the number of circuit blocks, using the same printed board.

FIG. 1 is a diagram for explaining the principle of the present invention. In FIG. 1, reference numeral 10 has a plurality of circuit blocks, a relay circuit, and a junction portion of a switching circuit. ,
A printed circuit board having a signal line pattern for transmitting a signal propagating between circuit blocks via a relay circuit and a signal line pattern for consolidating output signals of all the circuit blocks in a switching circuit, 20A, 20B ,. , 20N are circuit blocks, and 20A is a circuit block that is basically mounted (highest priority), and the priority is sequentially decreased below. 30B, ..., 30N are mounting priority. When the branch length branched from the signal line pattern that connects the output terminal of the circuit block and the input terminal of the switching circuit in the middle of two circuit blocks whose degrees differ from each other is open without mounting a relay circuit Is also placed at a position where the switching circuit does not malfunction due to signal reflection.
Reference numeral 40 denotes a relay circuit that relays a signal to a circuit block whose priority is one rank lower than that of the circuit block, and 40 selects an output signal from the circuit block having the lowest priority among the circuit blocks actually mounted. It is a switching circuit for outputting.

The present invention will be described with reference to FIG. In the present invention, the relay circuit is mounted when the corresponding circuit block is mounted, and is not mounted when the corresponding circuit block is not mounted. That is, the relay circuit 30B is mounted when the circuit block 20B is mounted, and the relay circuit 30C is mounted.
Is mounted when the circuit block 20C is mounted.
In addition, the circuit block has a priority level 1 higher than that of the circuit block.
It is mounted only when a circuit block having a high rank is mounted, and the circuit blocks are sequentially mounted in descending order of priority. That is, the circuit block 20B is mounted when the circuit block 20A is mounted, and the circuit block 20C is mounted when the circuit block 20B is mounted. In the switching circuit 40, the constituent components are selected, and only the output signal of the circuit block having the lowest priority among the circuit blocks actually mounted on the printed board 10 is output,
Actually, the output signals of all other circuit blocks are suppressed even when the circuit block is not mounted. Therefore,
The signal input to the printed circuit board is always output from the same terminal of the printed circuit board regardless of the number of mounted circuit blocks, and even if the relay circuit is not installed, no malfunction occurs due to signal reflection. The circuit block can be arranged at a free position in the printed board by providing the circuit block.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a switching circuit will be described with reference to FIGS. FIG. 2 shows a first embodiment of the switching circuit, and shows a case in which the input A is directly selected from the input A, the input B, and the input C to output, and FIG. 3 shows the second embodiment of the switching circuit. Yes, in selecting and outputting the input A from the input A, the input B, and the input C, first, the input A is selected from the input A and the input B, and then the input A is selected and output from the input A and the input C. . In addition, in FIGS. 2 and 3, when the other end of the resistor connected to the input terminal paired with the input signal of the logic element is + 5V,
The input signal is selected as a pull-up resistor, and when it is GND, the input signal is suppressed as a pull-down resistor. Therefore, in both FIGS. 2 and 3, the input A is selectively output. Next, the circuit configuration of the printed board will be described with reference to FIGS. 4 and 5. FIG. 4 is a circuit configuration diagram (1/2) of an embodiment of the present invention, showing a case where a central processing unit (hereinafter abbreviated as “CPU”) is mounted as a circuit block, and FIG. Circuit diagram (2 /
2) shows a case where a floating point arithmetic unit (hereinafter abbreviated as “FPU”) is mounted in addition to the CPU,
The structure of the printed circuit board which mounts the scan circuit for a diagnosis is shown. In FIGS. 4 and 5, reference numeral 21 denotes a CP composed of a large-scale integrated circuit (hereinafter abbreviated as “LSI”).
U is the circuit block that has the highest mounting priority and is basically mounted on the printed circuit board. 22 is an FPU composed of an LSI, and the mounting priority is next to the CPU, and it is mounted on the printed circuit board as an option. 30 is an integrated circuit (hereinafter, referred to as an integrated circuit) including a driver element.
"SSI") is a relay circuit mounted between the FPU 22 and the CPU 21 when the FPU 22 is mounted on the printed board. Reference numeral 40 denotes the output of the FPU when the CPU and the FPU are mounted. C if only mounted
Reference numeral 41 is a switching circuit that selectively outputs the output of the PU, reference numeral 41 is a switching circuit logic element section that is composed of logic elements in the switching circuit, and 42 is selected corresponding to the circuit block mounted in the switching circuit. A switching circuit resistance unit composed of a resistor, 51 is mounted when the FPU 22 is mounted,
A resistor (hereinafter, abbreviated as “pull-down resistor”) that sets the input of the logic element to logic “0”, 61 and 62 are FPU2.
This is a resistor that is mounted when 2 is not mounted and that sets the input of the logic element to logic "1" (hereinafter abbreviated as "pull-up resistor") and is exclusively mounted on the printed board as the pull-down resistor 51. Yes, 71, 72, 73, 74 are S
It is a logic element composed of SI. Hereinafter, FIGS. 4 and 5
The flow of the scan signal will be described with reference to FIG.
If the FPU 22 is not mounted on the printed circuit board 10, FIG.
As shown in FIG. 4, the relay circuit 30 is not mounted (the part surrounded by the dotted line in FIG. 4), and the pull-down resistor 51 is also not mounted (FIG. 4).
The part indicated by the dotted line in. The pull-up resistors 61 and 62 are mounted. Therefore, since the logic element 71 has all inputs of logic “1”, the output becomes logic “0” and the logic element 7
The output of logic element 73 will be a logic "1" regardless of the value of the other input connected to 3. On the other hand, the logic element 72
Since the input connected to the pull-up resistor 61 is a logic "1", the logic element 7 depends on the value of the output signal of the CPU 21.
An output signal is output from 2. Since the input of the logic element 74 connected to the logic element 73 is logic “0”, the logic element 74 outputs an output signal according to the value of the output signal of the logic element 72. When the FPU 22 is mounted on the printed board 10, the pull-up resistors 61 and 62 are not mounted (the portion indicated by the dotted line in FIG. 5). Since the relay circuit 30 and the pull-down resistor 51 are mounted, and therefore the inputs connected to the pull-down resistor 51 of the logic elements 71 and 72 are logic "0", the values of the output signals of the logic elements 71 and 72 are both logic. It is "1". Since the input connected to the output of the logic element 71 of the logic element 73 is the logic “1”, the output signal is output from the logic element 73 corresponding to the value of the output signal of the FPU 22. Logic element 7 connected to the output of logic element 72
Since the input of 4 is logic "1", the output signal of the logic element 74 is output according to the signal output from the logic element 73.

As described above, according to the present invention, the priorities to be mounted are determined in advance, the circuit blocks are continuously mounted in the order of the priorities, and the priorities are mounted in the order of the priorities to be mounted. The signal propagates from high to low,
Regardless of the number of circuit blocks mounted, the printed board output from the fixed terminal of the printed board can be designed using the same printed board, which shortens the design period, design cost, and management cost. ， Most contributes to the reduction of maintenance cost.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a first embodiment of a switching circuit.

FIG. 3 is a second embodiment of the switching circuit.

FIG. 4 is a circuit configuration diagram (1/2) of an embodiment of the present invention.

FIG. 5 is a circuit configuration diagram (2/2) of an embodiment of the present invention.

FIG. 6 is a conventional printed circuit board configuration diagram (1/2)

FIG. 7 is a conventional printed circuit board configuration diagram (2/2)

[Explanation of symbols]

 10 printed circuit board 20A, 20B, ..., 20N circuit block 30B, ..., 30N relay circuit 40 switching circuit 41 switching circuit logic element section 42 switching circuit resistance section 21 central processing unit (CPU) 22 floating point unit (FPU) 30 relay Circuit 51 Pull-down resistor 62,62 Pull-up resistor 71,72,73,74 Logic element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hitoshi Ogura Hitoshi Ogura, 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Pawnshai Chong Suvarna Paisan, 1015, Uedotaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited Incorporated (72) Inventor Eiji Kanaya 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (4)

[Claims] 1. A circuit block to be mounted in which priority levels are set and which are sequentially mounted in order of priority, and output signals of the circuit blocks are aggregated to give the highest priority from the mounted circuit blocks. It has a switching circuit that selects and outputs the output signal of a circuit block with a low frequency, and a joint that mounts the switching circuit and multiple circuit blocks. The joint of the output terminal of the circuit block and the joint of the input terminal of the switching circuit The signal line pattern that connects the parts with the printed circuit board that branches to the junction of the input terminals of the circuit block with one rank lower than the priority corresponds to the circuit block that is mounted with the components that make up the switching circuit. By selecting, the signal is sequentially propagated from the circuit block with high priority to the circuit block with low priority, and the circuit block with the lowest priority among the mounted circuit blocks is always A printed board characterized in that the output is made via the same printed circuit board terminal. 2. The component constituting the switching circuit selected according to the mounted circuit block according to claim 1,
A printed board characterized by being a resistor. 3. A circuit having a lower priority by one rank than the joint portion mounting the switching circuit, the joint portion mounting a plurality of circuit blocks, the joint portion of the output terminals of the circuit block and the joint portion of the input terminals of the switching circuit. A signal line pattern that connects the junctions of the input terminals of the block and a circuit block and a switching circuit are mounted, so that a signal that propagates from a circuit block with a high priority to a circuit block with a low priority is mounted. A printed circuit board which is output from a circuit block having the lowest priority within a certain range, and further, the signal is output from the same printed circuit board terminal regardless of the mounted circuit block. 4. The branch length from the signal line pattern connecting the joint of the output terminal of the circuit block and the joint of the input terminal of the switching circuit to the joint of the input terminal of the relay circuit is open without mounting the relay circuit. In the case of, the length is set so as not to cause malfunction due to signal reflection, and by having a relay circuit that relays a signal propagating from a circuit block to a circuit block whose priority is one rank lower,
The printed circuit board according to claim 1, wherein the circuit block can be freely arranged in the printed circuit board.