JPH06132962A - Device id setting circuit - Google Patents

Abstract

PURPOSE:To provide a device ID setting circuit which can be effectively produced, can flexibly cope with the change of a global address, etc., saving a space and also can easily recognize the device ID from the outside. CONSTITUTION:A device ID setting circuit contains plural setting basic circuits arrayed on a baby board. Each setting basic circuit is equivalent to one bit and contains the branching points of a wiring to be inputted to a driver 10 provided on the wiring connecting between resistance R where the voltage Vcc is impressed and the grounded jumper JP with the branching points on the sides of the resistance R and the jumper JP defined as the cut points 1 and 2 respectively. Then a device ID is set by cutting both points 1 and 2. Thus it is possible to externally recognize the device ID by checking the cut points, and it lets the CPU of an Ethernet main body recognize the device ID by the output from the driver 10 so as to flexibly cope with the ID change.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to Ethernet LA
The present invention relates to a device ID setting circuit that sets a device ID of a device connected to N, and particularly relates to a device ID setting circuit that can be efficiently produced, is easy to maintain, and does not take up space.

[0002]

2. Description of the Related Art First, Ethernet LAN (Local
The address of the device connected to the area network will be described. As shown in FIG. 3, the Ethernet LAN system is composed of one coaxial cable 1 and a plurality of devices (nodes) 2 connected to it. And
Since a plurality of nodes 2 need to identify each node in order to perform data communication via one cable 1, a unique address (global address or MAC address) is assigned to each node, Usually Et
The address is set on the Ethernet board connected to the Ethernet LAN.

The data sentence (packet) transmitted through the cable 1 is provided with the address of each node for identifying the destination node and the transmitting node, and each node once transmits the packet in the cable. It reads all the packets, selects the packets addressed to it from among them, and processes them.

A global address is usually 6 bytes of 1
It is represented by a hexadecimal number, and the upper 3 bytes are called a vendor ID, and are unique to the manufacturer of the Ethernet board.
D is semi-permanently assigned. And the lower 3
The byte is called a device ID, and is usually managed by an Ethernet board production maker so as to have an address unique to each device.

The global address of each node is one L
It must be unique within the AN system, and trouble will always occur if it overlaps, so it is set as a unique item for each device and can be changed by a third party, for example, DIP switch (Dip SW) Are prohibited (see IEEE 802.3).

A conventional global address setting method is as follows:
RO of firmware (F / W) consisting of 4 pieces
It was supposed to set a global address to one of M. In the ROM manufacturing procedure for setting the global address, first, the global address portion is'FF ', that is, the master ROM without data is copied as it is, and then the device-specific global address is overwritten. Then, a label with a global address is attached so that it can be identified by humans, and the operation check after assembly confirms whether the label with the global address and the displayed global address match. Was there.

[0007]

However, in the above-described conventional global address setting method, since the global address is different for each device, it is not possible to batch copy the ROM or to make it into the mask ROM, which results in efficient production. There was a problem that it could not be done.

Further, since the global address is written in the ROM, the contents of the address cannot be confirmed from the outside, and there is a problem that a label sticking error easily occurs.

Further, by enhancing the software,
When the ROM has to be exchanged, the global address is changed, so it is necessary to re-register it in the host computer, which causes a problem in the system operation.

The present invention has been made in view of the above-mentioned circumstances, and it enables efficient production, can flexibly respond to changes in global addresses, saves space, and externally uses the device I.
An object is to provide a device ID setting circuit that can easily recognize D.

[0011]

According to a first aspect of the present invention for solving the problems of the conventional example, a device ID setting circuit has a jumper grounded at one end and one end connected in series to the jumper. A driver that receives a resistance applied with a constant voltage at the other end and a wiring drawn from a branch point provided in a wiring that connects the jumper and the resistance, and outputs by receiving a control signal And a plurality of basic circuits including a first cut point provided between the resistor and the branch point and a second cut point provided between the jumper and the branch point. It is characterized by being arranged above.

According to a second aspect of the present invention for solving the problems of the conventional example, in the device ID setting circuit according to the first aspect, the first disconnection point is used to set the output from the driver to Low. Then, the output from the driver is High
However, the device ID is set by cutting at the second cutting point.

[0013]

According to the first aspect of the present invention, a branch point of the wiring for inputting to the driver is provided in the wiring connecting the resistor to which a constant voltage is applied and the grounded jumper, and the resistance side of the branch point. Is a first cut point, and a jumper side of the branch point is a second cut point, which is a device ID setting circuit in which a plurality of basic circuits are arranged on a board. Since the device ID setting circuit can be implemented on the board, the device can be downsized, and the device I can be set by checking the cut point.
The device ID can be recognized from the outside, and the device body can recognize the device ID by the value output from the driver by the control signal.
Can be flexibly dealt with, and mass production can be performed without being aware of the device ID in the production stage.

According to the second aspect of the invention, since the device ID is represented by the output of High or Low from the driver,
The first disconnection point is disconnected to set the output from the driver to Low, and the second disconnection point is disconnected to output the output from the driver to Hi.
Since the device ID is set as gh, the device ID setting circuit according to claim 1 allows the device ID to be recognized from the outside by looking at the disconnection point, and the value output from the driver by the control signal The device ID in order to allow the Ethernet body to recognize the device ID
It is possible to flexibly respond to changes in.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a device ID according to an embodiment of the present invention.
FIG. 2 is a basic setting circuit diagram for 1 bit in the setting circuit, and FIG. 2 is a schematic diagram of a baby board in which three chips (ICs) including eight circuit elements of FIG. 1 are arranged.

In the global address setting method using the device ID setting circuit of the present embodiment, the vendor ID, which is semi-permanently determined uniquely to the board maker among the global addresses, is kept stored in the ROM as before. Device ID set uniquely for each device (3 bytes = 24
Bit) is realized by the baby board shown in FIG.

First, a basic circuit for setting the device ID 1 bit will be described. The basic circuit for setting the device ID 1 bit is, as shown in FIG. 1, a jumper JP (zero ohm resistor or printed pattern) grounded to the ground,
A resistor R connected in series with the jumper JP, and a jumper JP
And a resistor R, which is branched and connected between the resistor R and the resistor R, and the voltage Vcc is applied to the resistor R and the jumper JP from the resistor R side.

The output of the driver 10 is Ether
Connected to the CPU bus of the net board body, and driver 1
For 0, a control signal for chip select is input from the Ethernet board main body.

Then, the value of each bit shown in FIG. 1 is set to Low.
Or to set to High, cutting point 1 or cutting point 2
To disconnect the circuit. Specifically, when the circuit is disconnected at the disconnection point 1, it becomes a series circuit of the jumper JP and the driver 10 which are grounded, and the Low value is output to the CPU bus. Conversely, when the circuit is disconnected at the disconnection point 2, the voltage Vcc is It becomes a series circuit of the applied resistance R and the driver 10, and Hi to the CPU bus
The value of gh will be output. In this way, the Low or High value of each bit is determined.

Next, the device ID setting circuit of this embodiment will be described with reference to FIG. As shown in FIG. 2, the device ID setting circuit includes the basic circuit of FIG.
The four chips are arranged side by side, and the driver 10 is integrated into an IC.
44) is used, and the resistor section 12 is provided on the upper side of the IC11 section.
However, the jumper JP portion 13 is arranged below the IC 11 portion so that the cut points 1 and 2 of each basic circuit can be confirmed from the outside.

The output from each driver 10 is connected to the Ethernet board main body through 24 pins provided on the lower portion of the baby board 14 and output to the CPU bus.

In this embodiment, the entire device ID setting circuit is realized on a SiP type printed board (baby board) of about 40 mm × about 20 mm.

When manufacturing the device ID setting circuit of the present embodiment, first, a large number of baby boards of FIG. 2 in which 24 basic circuits of FIG. 1 are mounted are manufactured, and then, according to the device ID to be set, The cut point 1 or the cut point 2 of each basic circuit on the baby board is cut. As a result, a 24-bit Low or High value is set on the baby board, the baby board is connected to the Ethernet board body, and the chip select control signal from the Ethernet board body is sent to the driver 10 of each basic circuit. When it is given to, the value of Low or High is output, and the set device ID is output to the CPU bus.

According to the device ID setting circuit of the present embodiment, mass production can be performed without being aware of the device ID at the baby board production stage, so that the production efficiency can be improved. Further, the setting of the device ID that is unique to each device determines High or Low depending on the position of the cut point of each basic circuit on the baby board, and the value becomes "1" or "0" to form the device ID. Therefore, it is possible to confirm the device ID only by recognizing the cutting point position from the outside, and it is possible to reduce human errors such as a labeling error.

Since the device ID setting circuit can be realized in the size of a baby board, the device itself can be miniaturized. Further, when the ROM needs to be replaced due to the enhancement of the software and the device ID is changed, the CPU of the Ethernet board body can be simply replaced by the baby board in which the changed device ID is set. Since the CPU can recognize the changed device ID by outputting the chip select control signal, there is an effect that the software does not require a structural change and the maintenance can be facilitated.

[0026]

According to the first aspect of the invention, a branch point of a wiring for inputting to a driver is provided in a wiring connecting a resistor to which a constant voltage is applied and a jumper grounded, and the branch point Since a device ID setting circuit is formed by arranging a plurality of basic circuits on the board, the resistor side being the first cutting point and the jumper side of the branching point being the second cutting point. Since it becomes possible to set the ID, and therefore the device ID setting circuit can be realized on the board, the device can be downsized, and the device ID can be recognized from the outside by looking at the cut point. Further, depending on the value output from the driver by the control signal, the Ethernet
Since the et main body can recognize the device ID, it is possible to flexibly deal with the change of the device ID, and it is possible to mass-produce without being aware of the device ID in the production stage.

According to the second aspect of the invention, since the device ID is represented by the output of High or Low from the driver,
The first disconnection point is disconnected to set the output from the driver to Low, and the second disconnection point is disconnected to output the output from the driver to Hi.
Since the device ID is set as gh, the device ID setting circuit according to claim 1, the device ID can be recognized from the outside by looking at the cutting point, and the value output from the driver by the control signal can be used. The device ID in order to allow the Ethernet body to recognize the device ID
The effect of being able to flexibly respond to changes in

[Brief description of drawings]

FIG. 1 is a circuit diagram of a setting basic circuit for 1 bit in a device ID setting circuit according to an embodiment of the present invention.

FIG. 2 shows a chip (IC) including eight circuit elements of FIG.
It is the schematic of the baby board of the present Example arranged individually.

FIG. 3 is a configuration diagram of a general Ethernet LAN system.

[Explanation of symbols]

1 ... coaxial cable, 2 ... node, 10 ... driver,
11 ... IC, 12 ... Resistor part, 13 ... JP part, 1
4 ... Baby board, JP ... Jumper, R ... Resistance,
PB ... Printed circuit board

Claims (2)

[Claims] 1. A jumper whose one end is grounded, a resistor whose one end is connected in series to the jumper and a constant voltage is applied to the other end, and wiring which connects the jumper and the resistor. A wiring that is drawn from the branch point is input, and a driver that outputs by inputting a control signal; a first disconnection point provided between the resistor and the branch point;
A device ID setting circuit comprising a plurality of basic circuits arranged on a board, the basic circuit having a second cutting point provided between the jumper and the branch point. 2. The output from the driver is set to H at the first disconnection point in order to set the output from the driver to Low.
Even if it is set to high, the device ID is obtained by cutting at the second cutting point.
The device ID setting circuit according to claim 1, wherein: