Apparatus and method for controlling device connection

• US 6,477,605 B1
• Filed: 03/04/1999
• Issued: 11/05/2002
• Est. Priority Date: 08/21/1998
• Status: Expired due to Term

• Current Assignee: Trinity Semiconductor Research G.k.
• Original Assignee: Fujitsu Limited
• Inventors: Tomita, Masato, Makabe, Hideo, Taki, Nobuhiro
• Primary Examiner(s): AUVE, GLENN ALLEN
• Application Number:
  US09/262,007
• Time in Patent Office: 1,342 Days
• Field of Search: 710/302, 710/104, 713/100, 713/300, 713/310, 713/320, 713/340, 709/217, 709/218, 709/224, 709/229
• US Class Current: 710/302
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A connection device for connecting electronic devices via a network allows activates its status signal in response to a data transfer operation or in response to receiving a remote status signal. By limiting the activation of the status signal, the connection device reduces the power consumption of the electronic devices. The connection device also performs plug-and-play initialization to prevent device conflicts and allow for hot plug-in of electronic devices.

Claims

1. A connection control apparatus for controlling a connection between a local node and a remote node by sending and receiving a status signal therebetween, comprising:

a status generation circuit generating a local status signal;

a status detection circuit for receiving a remote status signal generated at the remote node and for detecting a state of the received remote status signal;

a status control circuit, connected to the status generation circuit and the status detection circuit, for selectively controlling the status generation circuit, wherein the status control circuit disables the status generation circuit when the detected state of the remote status signal denotes deactivation and enables the status generation circuit when the local node starts sending data, the local node starts receiving data, or the detected state of the remote status signal denotes activation.

2. The apparatus of claim 1, wherein the status control circuit further enables the status generation circuit when the local node detects that it is connected to the remote node.

3. The apparatus of claim 1, wherein the status control circuit enables the status generation circuit in response to power-on in the local node.

4. The apparatus of claim 1, wherein the status control circuit disables the status generation circuit when the detected remote status signal denoting deactivation is detected after a predetermined time has elapsed from when the status generation circuit was enabled.

5. The apparatus of claim 1, wherein the status control circuit disables the status generation circuit in response to a request from the local node indicating that interference of the remote node has been ignored when the local node and the remote node are connected together.

6. The apparatus of claim 1, wherein the status control circuit disables the status generation circuit when the local node has not output any data for a predetermined period and when there has been no data transmission from the remote node during the predetermined period.

7. The apparatus of claim 1, wherein the status control circuit disables the status generation circuit in response to a request from the local node indicating that the connection with the remote node is disconnected.

8. The apparatus of claim 1, further comprising:

a PLL circuit, connected to the status control circuit, for receiving a reference clock signal and generating an internal clock signal having a predetermined frequency;

wherein the status control circuit disables the PLL circuit when the status generation circuit is disabled.

9. The apparatus of claim 8, wherein the status control circuit generates a selection signal, and

the connection control apparatus further comprising a selector, connected between the PLL circuit and the status control circuit, for receiving the reference clock signal, the internal clock signal, and the selection signal, and supplying one of the reference clock signal and the clock signal to the status control circuit in accordance with the selection signal.

10. The apparatus of claim 9, further comprising an oscillator, which generates the reference clock signal, and wherein the status control circuit generates a control signal for inhibiting the reference clock signal from the oscillator when the status generation circuit is deactivated.

11. The apparatus of claim 1, further comprising a PLL circuit, connected to the status control circuit, for receiving a reference clock signal and generating an internal clock signal having a predetermined frequency,

wherein the status control signal maintains the PLL circuit in an operating state when the status generation circuit is disabled.

12. The apparatus of claim 11, wherein the status control circuit controls the PLL circuit to reduce the internal clock frequency.

13. The apparatus of claim 12, further comprising an oscillator, which generates the reference clock signal, and wherein the status control circuit controls the oscillator so that the frequency of the reference clock signal is reduced when the status generation circuit is disabled.

14. The apparatus of claim 1, wherein the connection control apparatus is connected to a processing unit, and the status control circuit disables the processing unit when the status generation circuit is disabled.

15. The apparatus of claim 1, further comprising a plurality of ports, wherein a plurality of pairs of the status generation circuits and status detection circuits are connected to the plurality of ports, respectively;

and

wherein the status control circuit enables the status generation circuits connected to all of the ports when at least one of the status detection circuits detects activation of the remote status signal.

16. The apparatus of claim 1, further comprising a plurality of ports, wherein a plurality of pairs of the status generation circuits and status detection circuits are connected to the plurality of ports, respectively;

and

wherein, when the status detection circuit connected to any one of the ports detects activation of the remote status signal and the status detection circuits connected to the remaining ports detect deactivation of the remote status signal, the status control circuit disables the status generation circuit connected to the remaining ports.

17. The apparatus of claim 1, further comprising:

a driver for sending data from the local node; and

a receiver for receiving data from the remote node;

wherein the status control circuit disables the driver and the receiver when the status generation circuit is disabled.

18. The apparatus of claim 17,

wherein the status control circuit enables the driver and the receiver when the status generation circuit is enabled.

19. A method for controlling a connection between a local node and a remote node by sending and receiving a status signal therebetween, the local node and the remote node each being connected to a connection control apparatus, each connection apparatus including a status generation circuit for generating a local status signal and a status detection circuit for detecting a remote status signal generated by the status generation circuit of the connection controller of the remote node, the method comprising the steps of:

disabling the status generation circuit when deactivation of the remote status signal is detected by the status detection circuit; and

enabling the status generation circuit when the local node starts sending data, the local node starts receiving data, or when activation of the remote status signal is detected.

20. The method of claim 19, wherein the enabling step includes enabling the status generation circuit when the local node checks and determines that it is connected to the remote node.

21. The method of claim 19, wherein the enabling step includes enabling the status generation circuit in response to power-on in the local node.

22. The method of claim 19, wherein the disabling step includes disabling the status generation circuit when deactivation of the remote status signal is detected after a predetermined time has elapsed from when the status generation circuit is enabled.

23. The method of claim 19, wherein the disabling step includes disabling the status generation circuit in response to a request from the local node indicating that interference of the remote node has been ignored when the local node and the remote node are connected together.

24. The method of claim 19, wherein the disabling step includes disabling the status generation circuit when the local node has not output any data for a predetermined period and when there has been no data transmission from the remote node for the predetermined period.

25. The method of claim 19, wherein the disabling step includes disabling the status generation circuit in response to a request from the local node indicating that the remote node is disconnected from the local node.

26. The method of claim 19, wherein the connection control apparatus further includes a plurality of ports, and a plurality of pairs of the status generation circuits and status detection circuits are connected to the plurality of ports, respectively, and

wherein the enabling step includes enabling the status generation circuits connected to all of ports when the status detection circuit connected to at least one of the ports detects activation of the remote status signal.

27. The method of claim 19, wherein the connection control apparatus further includes a plurality of ports, and a plurality of pairs of the status generation circuits and status detection circuits are connected to the plurality of ports, respectively, and

wherein, when the status detection circuit connected to any one of the ports detects activation of the remote status signal and the status detection circuit connected to the remaining ports detect deactivation of the remote status signal, the disabling step includes disabling the status generation circuits connected to the remaining ports.

28. A connection device for connecting an electronic device to a remote device via a network, comprising:

a net interface circuit connected to a network for transmitting a local status signal over the network and for receiving a remote status signal transmitted over the network;

a local status generation circuit connected to the net interface circuit, the local status generation circuit generating the local status signal in response to a control signal;

a remote status detection circuit connected to the net interface circuit, the remote status detection circuit detecting a remote status signal received by the net interface circuit, wherein in response to detecting the remote status signal, the remote status detection circuit activates a detection signal;

a host interface circuit connected to the electronic device for passing data to the electronic device and for receiving data from the electronic device;

a data transfer circuit connected between the host interface circuit and the net interface circuit for passing data therebetween and for generating a data transfer control signal indicating that data is to be transferred between the remote device and the electronic device; and

a status control circuit connected to the local status generation circuit for providing the control signal thereto, connected to the remote status detection circuit for receiving the remote status signal, and connected to the data transfer circuit for receiving a data transfer control signal therefrom, wherein the status control circuit activates the control signal in response to the data transfer control signal or the detection signal.