JP2004094852A - Resume control device for universal serial bus (usb) - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resume control device for a USB capable of recovering from a suspend state to a normal operation state without re-inserting a cable or connector of the USB even in a peripheral device requiring a long time for resuming. <P>SOLUTION: The peripheral device electrically connects a first pull-up means to a signal line and electrically detaches a second pull-up means from the signal line when in a suspend state. When receiving a signal instructing from a host device to resume, it is controlled that the second pull-up means is electrically connected to the signal line in a state that the first pull-up means is electrically connected to the signal line, and that the second pull-up means is electrically detached from the signal line after the resuming is completed. The host device detects a voltage of the signal line and changes a maximum waiting time until the peripheral device resumes based on the detected voltage of the signal line. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a USB resume control device that controls an operation when a peripheral device connected to a host device via a USB (Universal Serial Bus) resumes (returns) from a suspended state (hibernation state) to a normal operation state. It is about.
[0002]
[Prior art]
USB is one of the standards for serially connecting a host device such as a personal computer and peripheral devices such as a mouse and a keyboard. At present, a product conforming to the USB 2.0 standard, which is a faster version of the USB 1.1 standard, has been commercialized. The host device and the peripheral device are connected by four signal lines (via a cable or directly connected) of a positive side signal line and a negative side signal line (D +, D−), a power supply line (VBUS), and a ground line (GND).
[0003]
When the peripheral device connected to the host device via the USB has not been used for a predetermined period of time, in order to reduce power consumption, the host device sends the peripheral device via the signal lines (D +, D-) to the peripheral device. A signal for instructing a transition to a suspend state (pause state) is transmitted. According to this signal, the peripheral device shifts to the suspend state.
[0004]
On the other hand, when the host device uses the peripheral device in the suspended state, the host device instructs the peripheral device in the suspended state to return to the normal operation state via the signal lines (D +, D-). Is sent. According to this signal, the peripheral device resumes (returns) from the suspend state to the normal operation state.
[0005]
The USB standard defines a maximum waiting time for a peripheral device connected to a host device to resume from a suspended state to a normal operation state. This allows the host device to resume the normal operation state when the peripheral device connected to the host device is in an inoperable state for some reason after the peripheral device is suspended, for example. Prevents waiting.
[0006]
However, depending on the type of the peripheral device and its suspend state, it may take longer than the maximum wait time of the resume in the USB standard before resuming to the normal operation state. For example, a peripheral device having an oscillation circuit requires a predetermined time until the oscillation frequency of the oscillation circuit is stabilized. Further, for example, a peripheral device such as a hard disk requires a predetermined time until the rotation of the disk is stabilized.
[0007]
The host device determines that the peripheral device is not operable unless a signal notifying that the device has resumed the normal operation state is not transmitted from the peripheral device within the maximum wait time for the resume. For this reason, a peripheral device that does not complete the resume even after exceeding the maximum wait time for the resume cannot resume to the normal operation state.
[0008]
Conventionally, in the case of such a peripheral device, it is necessary to disconnect the USB cable or connector from the host device, remove the peripheral device, and then reconnect the peripheral device to reconnect the peripheral device to the host device, which is very troublesome. There was a problem.
[0009]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to solve the problems based on the prior art, and to return from a suspended state to a normal operation state without re-plugging a USB cable or connector, even for a peripheral device requiring a long time to resume. It is an object of the present invention to provide a USB resume control device.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a USB resume control device for controlling the operation of a host device and a peripheral device connected via USB when the peripheral device resumes from a suspended state to a normal operation state. And
The host device is connected to the USB signal line, and detects voltage of the signal line. The peripheral device resumes based on the voltage of the signal line detected by the voltage detection unit. And a wait time changing means for changing a maximum wait time until the USB resume control device.
[0011]
The present invention is also a USB resume control device that controls an operation when the peripheral device resumes from a suspended state to a normal operation state in a host device and a peripheral device connected via USB.
The peripheral device includes first and second pull-up units physically connected in parallel to the USB signal line, and electrically connects the first pull-up unit to the signal line when in a suspend state. Connected, and electrically disconnects the second pull-up means from the signal line, and electrically connects the first pull-up means to the signal line when receiving a signal indicating resume from the host device. The second pull-up means is electrically connected to the signal line while being connected, and the control is performed such that the second pull-up means is electrically disconnected from the signal line after the resume is completed. A USB resume control device comprising a control unit.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a USB resume control device of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
[0013]
FIG. 1 is a schematic configuration diagram of one embodiment of a USB resume control device of the present invention. The USB resume control device 10 according to the present embodiment includes a host device 12 such as a personal computer and a peripheral device 14 such as a mouse or keyboard connected to the host device 12 via a USB (via a cable or directly connected). It has. The space between the host device 12 and the peripheral device 14 is shown separated by a dotted line in the figure.
[0014]
In the USB resume control device 10, the host device 12 includes a comparator 16 and a waiting time changing circuit 18.
[0015]
In the host device 12, the comparator 16 is connected to the USB positive signal line (D +), detects the voltage of the positive signal line (D +) by comparing with a reference voltage, and detects the detection result. And outputs signals S1 and S2.
[0016]
Further, the waiting time changing circuit 18 is connected to the comparator 16, and based on the detection results S1 and S2 of the comparator 16, ie, the voltage of the positive signal line (D +), the maximum waiting time until the peripheral device 14 resumes. Change the time. More specifically, the waiting time changing circuit 18 switches between the maximum waiting time of the resume conforming to the USB standard and the maximum waiting time of the resume extended according to the present invention, based on the detection results S1 and S2.
[0017]
On the other hand, in the USB resume control device 10, the peripheral device 14 includes two pull-up resistors (R1, R2) 20, 22 and a clock counter 24.
[0018]
In the peripheral device 14, the pull-up resistor 20 is connected between the signal line (D +) and an internal circuit (not shown) of the peripheral device, and the pull-up resistor 22 is connected to the signal line (D +) and the clock counter 24. Connected between. The electrical connection / disconnection of these pull-up resistors 20 and 22 to the positive signal line (D +) is controlled according to the state of the pull-up control lines 1 and 2.
[0019]
That is, the pull-up resistors 20 and 22 are electrically connected to the positive signal line (D +) when the pull-up control lines 1 and 2 reach, for example, a power supply voltage, and are electrically disconnected when the pull-up resistors 20 and 22 enter a floating state. .
[0020]
The clock counter 24 is connected to an internal circuit (not shown) of the peripheral device 14. The clock counter 24 uses the pull-up control line 2 as the power supply voltage during the resume, counts the clock signal generated inside the peripheral device 14 after the resume, and when the counted number reaches a predetermined constant value, The pull-up control line 2 is controlled to be in a floating state.
[0021]
In the USB resume control device 10 shown in FIG. 1, only the characteristic components of the present invention are shown in both the host device 12 and the peripheral device 14. It goes without saying that the host device 12 and the peripheral device 14 each include various components other than those shown in FIG. The components other than the illustrated components are not limited at all, and may include any components as necessary.
[0022]
The specific circuit configuration of the comparator 16 is not limited at all. Further, the means for detecting the voltage of the positive signal line (D +) is not limited to the comparator 16, and any conventionally known means that can detect the voltage of the positive signal line (D +) can be used. Such a circuit can also be used. Further, the specific circuit configuration of the waiting time changing circuit 18 is not limited at all, and any circuit having the same function may be used.
[0023]
The pull-up resistor 20 is used in a conventionally known USB. On the other hand, the pull-up resistor 22 is a component unique to the present invention, and one or a plurality of resistors may be used. By configuring the pull-up resistor 22 with a plurality of resistors, the number of types of voltages on the positive signal line (D +) detected by the comparator 16 can be further increased, and the switching of the maximum waiting time can be increased. It is also possible to select from the types.
[0024]
The specific circuit configuration of the clock counter 24 is not limited at all, and a conventionally known counter circuit can be used. Further, the present invention is not limited to the use of the clock counter 24, and any circuit having an equivalent function may be used.
[0025]
Next, the operation of the USB power supply control device 10 of the present invention will be described.
[0026]
According to the USB standard, there are three types of operation modes, low speed (LS), full speed (FS), and high speed (HS), according to the difference in transfer speed. In the FS mode, the pull-up resistor 20 of the peripheral device 14 is always electrically connected to the positive signal line (D +). On the other hand, in the HS mode, the pull-up resistor 20 is electrically disconnected from the positive signal line (D +) except when the peripheral device 14 is in the suspended state.
[0027]
In the case of the present embodiment, as shown in the table of FIG. 2, the pull-up resistor 20 is off (that is, when it is electrically disconnected from the positive signal line (D +)), and the pull-up resistor 22 is also off. In this case, the voltage of the positive signal line (D +) is V0. In this case, the detection results S1 and S2 of the comparator 16 are L and L, which means that the peripheral device 14 is not connected to the host device 12 or is in a normal operation state (HS mode).
[0028]
Further, when the pull-up resistor 20 is turned on (that is, when electrically connected to the positive signal line (D +)) and the pull-up resistor 22 is turned off, the voltage of the positive signal line (D +) is turned off. Is V1. In this case, the detection results S1 and S2 of the comparator 16 become H and L, which means that the peripheral device 14 is in the normal operation state (FS mode) or the suspended state.
[0029]
Further, the voltage of the signal line (D +) on the positive side when both the pull-up resistors 20 and 22 are on is V2. In this case, the detection results S1 and S2 of the comparator 16 become H and H, which means that the peripheral device 14 is in the process of resuming. It should be noted that the relationship is not limited to the relationship shown in the table of FIG. May be changed to
[0030]
When the peripheral device 14 is physically connected to the host device 12 via USB, the state of the pull-up control line 1 is controlled, and the pull-up resistor 20 is electrically connected to the positive signal line (D +). Is done. Thereby, the voltage of the signal line (D +) on the positive side changes from V0 to V1. The host device 12 detects the voltage V1 of the positive signal line (D +) by the comparator 16 and recognizes that the peripheral device 14 is connected.
[0031]
As described above, the pull-up resistor 20 is electrically connected to the positive signal line (D +) even after the connection between the host device 12 and the peripheral device 14 is established in the FS mode. It is left as it is. On the other hand, in the case of the HS mode, the pull-up resistor 20 is electrically disconnected from the positive signal line (D +) after the connection between the host device 12 and the peripheral device 14 is established.
[0032]
When a predetermined period of time elapses without using the peripheral device 14, the host device 12 transmits a signal instructing to shift to the suspend state to the peripheral device 14 via the signal lines (D +, D-). Upon receiving this signal, the peripheral device 14 shifts to the suspend state. In the suspend state, the connection in the FS mode is maintained regardless of the USB operation mode in the normal operation state. That is, the pull-up resistor 20 is electrically connected to the positive signal line (D +).
[0033]
Thereafter, if necessary, a signal instructing the peripheral device 14 to resume from the suspend state to the normal operation state is transmitted from the host device 12 to the peripheral device 14. At this time, in the peripheral device 14, the state of the pull-up control line 2 is controlled by the clock counter 24, and the pull-up resistor 22 is electrically connected to the positive signal line (D +). As a result, the voltage of the signal line (D +) on the positive side changes to V2.
[0034]
The host device 12 detects the voltage V2 of the signal line (D +) on the positive side by the comparator 16, and the peripheral device 14 is not in an inoperable state but is being resumed, and the resume requires a long time. Recognize. Then, based on the detection results S1, S2 = H, H, the waiting time changing circuit 18 switches from the maximum waiting time of the resume conforming to the USB standard to the maximum waiting time of the resume extended according to the present invention.
[0035]
Accordingly, the peripheral device 14 shifts from the resume state to the normal operation state after a predetermined period of time without timeout. That is, the clock counter 24 controls the state of the pull-up control line 2 after counting a predetermined count number of clock signals set in advance, and the pull-up resistor 22 is electrically connected to the positive side signal line (D +). Be cut off. As a result, the voltage of the positive signal line (D +) changes to V1.
[0036]
The host device 12 detects the voltage V1 of the positive signal line (D +) using the comparator 16, and recognizes that the peripheral device 14 has shifted to the normal operation state from the change in the voltage. Thereafter, a signal for changing the USB operation mode is transmitted from the host device 12 to the peripheral device. According to this signal, the peripheral device 14 turns off the pull-up resistor 20 in the high-speed mode, and otherwise maintains the current state.
[0037]
The host device 12 and the peripheral device 14 are usually sold as independent products. Therefore, it goes without saying that only the host device 12 to which the present invention is applied or only the peripheral device 14 to which the present invention is applied is included in the scope of the present invention.
[0038]
When a peripheral device to which the present invention is applied is connected to a host device that conforms to the existing USB 1.1 and 2.0 standards, and a peripheral device that conforms to the existing USB 1.1 and 2.0 standards, When connected to the host device to which the present invention is applied, the host device and the peripheral device to which the present invention is applied operate exactly the same as the host device and the peripheral device conforming to the existing USB 1.1 and 2.0 standards. Is possible.
[0039]
That is, the host device and the peripheral device to which the present invention is applied can coexist with the host device and the peripheral device conforming to the existing USB 1.1 and 2.0 standards. In addition, when the peripheral device 14 to which the present invention is applied is connected to the host device 12 to which the present invention is applied, the maximum wait time of the resume is changed, and the peripheral device is resumed without timeout. It becomes possible.
[0040]
The present invention is basically as described above.
As described above, the USB resume control device of the present invention has been described in detail. However, the present invention is not limited to the above embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.
[0041]
【The invention's effect】
As described in detail above, in the USB resume control device of the present invention, the peripheral device electrically connects the first pull-up means to the signal line and sets the second pull-up means in the suspend state. Is electrically disconnected from the signal line, and when a signal indicating a resume is received from the host device, the second pull-up means is electrically connected to the signal line while the first pull-up means is still electrically connected to the signal line. And electrically disconnects the second pull-up means from the signal line after the resume is completed. Further, the host device detects the voltage of the signal line, and changes the maximum waiting time until the peripheral device resumes based on the detected voltage of the signal line.
Thus, according to the USB resume control device of the present invention, the host device can determine whether the peripheral device is simply taking a long time to resume or has become inoperable. The host device can return from the suspended state to the normal operation state without re-plugging the USB cable or connector even if the peripheral device requires a long time to resume.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of one embodiment of a USB resume control device of the present invention.
FIG. 2 is a table showing a relationship between output results S1 and S2 of comparators and states of peripheral devices in the USB resume control device shown in FIG. 1;
[Explanation of symbols]
Reference Signs List 10 Resume control device for USB 12 Host device 14 Peripheral device 16 Comparator 18 Waiting time change circuit 20, 22, Pull-up resistor 24 Clock counter

Claims (2)

A USB resume control device for controlling an operation when the peripheral device resumes from a suspended state to a normal operation state in a host device and a peripheral device connected via a USB,
The host device is connected to the USB signal line, and detects voltage of the signal line. The peripheral device resumes based on the voltage of the signal line detected by the voltage detection unit. And a waiting time changing means for changing a maximum waiting time until the resume control device for USB. A USB resume control device for controlling an operation when the peripheral device resumes from a suspended state to a normal operation state in a host device and a peripheral device connected via a USB,
The peripheral device includes first and second pull-up units physically connected in parallel to the USB signal line, and electrically connects the first pull-up unit to the signal line when in a suspend state. Connected, and electrically disconnects the second pull-up means from the signal line, and electrically connects the first pull-up means to the signal line when receiving a signal indicating resume from the host device. The second pull-up means is electrically connected to the signal line while being connected, and the control is performed such that the second pull-up means is electrically disconnected from the signal line after the resume is completed. A resume control device for USB, comprising: a control unit.

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