JPH027119A - Protecting circuit for inserting and extracting package in hot-line - Google Patents

Abstract

PURPOSE:To prevent a malfunction due to the fact that a driver gives the bad influence to a system bus by making ineffective a buffer between a backboard and a package when the package is inserted and extracted. CONSTITUTION:When a package (PKG) is inserted in hot-line, the power source is supplied from an external supply power source 1 to the PKG beforehand, and thus, a power-on resetting signal is generated from a resetting circuit 3. Further, an external power source detecting circuit 2 detects that a power source 1 is connected and sends the power source detecting signal to a driver control 5. The control 5 controls a buffer 6 of a system bus 7 between the PKG and backboards and an ineffective signal is sent by a power source detecting signal from the circuit 2 to the buffer 6. After the PKG is inserted into the sub-rack, the power source 1 is removed, and after the PKG is initialized, the output of the buffer 6 is activated by the command from a CPU 4.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used in a data transmission device, and when inserting a package into the data transmission device and removing the package,
This invention relates to a protection circuit for protecting MUX buses, CPU buses, etc.

[Conventional technology]

Conventionally, when hot-swapping, such as inserting and removing packages in data transmission equipment, it was used to protect the equipment.

The length of the contact electrode of the card edge connector part of the package (hereinafter abbreviated as PKG) is changed, and the GND (ground), power supply, and signal lines are connected to the system bus in this order. Additionally, measures have been taken such as inserting a coil into the power supply line (on the PKG) to prevent rush current.

[Problem to be solved by the invention]

In the case of the conventional device protection described above, the length of the contact electrode of the card edge connector part of the PKG is changed to connect GND, power supply,
Since the signal lines are connected to the system bus in that order, and the signal lines, power supply, and GND are disconnected from the system bus in that order, the problem is that the PKG driver output is unstable and has a negative effect on the system bus. There is. [Means for Solving the Problems] According to the present invention, it is used when inserting and removing a package into and from a subrack that accommodates the package.

A package activity characterized by having a detection means for detecting that a power source is connected to the package, and a control means for disabling a driver means connected to a system bus upon receiving a detection signal from the detection means. A protection circuit for wire insertion/extraction is obtained.

〔Example〕

Next, the present invention will be explained with reference to examples.

First, referring to FIGS. 1 and 2, when inserting a PKG into a hot line, external power supply 1 supplies power to PKG 9 in advance. As a result, a power-on reset signal is generated from the reset circuit 3.

Furthermore, the external power supply detection circuit 2 detects that the power supply 1 is connected, and sends a power supply detection signal to the driver control 5. PK in driver control 5
The control means for the buffer 6 of the system bus between the G and backboards is configured to disable the buffer 6 based on the power supply detection signal from the external power supply detection circuit 2.
) send a signal. After inserting the PKG into the subrack, remove the external power supply 1 and initialize the PKG. Then, the CPU 4 gives a command to the driver control 5 to enable the output of the buffer 6 (E
nable ).

Similarly, when removing a PKG, power is supplied from the front in advance, the buffer 6 is disabled, and the PKG is removed from the subrack.

Next, a specific example will be explained with reference to FIG.
(The reset circuit 3 of FIG. 1 is not shown in FIG. 3). When an external power source (not shown) is connected to the front power terminal 10,
A level signal is output from the inverter 8, and as a result,
- A low level signal is given to the flip-flop 9,
Flip-flop 9 outputs a low level. As a result, a low level is output from the AND gate 11, and the buffer 6 is made invalid.

On the other hand, when the external power supply is removed from the front power supply terminal lO,
The inverter 8 outputs the no-repel signal, and as a result, the flip-flop 9 outputs a high level signal, and the buffer 6 is enabled.

〔Effect of the invention〕

As explained above, in the present invention, when inserting and removing the PKG, power is supplied from the outside and the buffer between the backboard and the PKG is disabled.

This has the effect of preventing the driver from adversely affecting the system bus and causing malfunctions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a protection circuit according to the first invention. FIG. 2 is a diagram for explaining the operation of the protection circuit of FIG. 1, and FIG. 3 is a diagram showing a specific example of FIG. 1. l...External power supply, 2...External power supply detection circuit. 3... Reset circuit, 4... CPU, 5... Driver control, 6°°° buffer, 7 system bus. 8...Inverter, 9...Flip-flop. ■Δ when inserting PKθ” (company) - Figure 2 (-embedding (7733) Patent attorney Asaho Ikeda

Claims (1)

[Claims] 1. A detection means used when a package is inserted into or removed from a subrack that accommodates the package, and detects that a power supply is connected to the package, and a detection means that is connected to the system bus upon receiving a detection signal from the detection means. A protection circuit for package hot-swapping, characterized in that it has a control means for disabling a driver means.