JP2006099354A - Data transfer control device and data transfer control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a USB OTG device that prevents data transfer from being interrupted by switching a power supply slave to a power supply master or vice versa and power supply devices without replacing a USB cable even while data are transferred between devices each of which has a USB OTG. <P>SOLUTION: An OTG device is provided with a power supply monitor 11 for monitoring the residual capacity of a rechargeable battery 13 to determine whether or not switching between the power supply master and the power supply slave is permitted. Further, an OTG state machine control part 16 is newly provided with a state p_idle for switching of the power supply master. When switching of the power supply master is executed, a transition to a p_idle state is made while set data are retained. In the p_idle state, the power supply master stops the supply of Vbus while the power supply slave starts supplying Vbus after confirming that the level of Vbus is not greater than a threshold. Once the level of Vbus is at or greater than the threshold, a transition to the state of data transfer is made and a process prior to the process of switching the power supply master is continued. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power supply control and a data transfer control method in a portable data transfer apparatus. In particular, the present invention relates to a portable terminal device having a USB OTG (On-The-Go) function.

  There is a USB standard as a standard for performing data transfer in a portable device. In the conventional USB standard, in order for a peripheral device to transfer data, a host device (for example, a PC) is always required, and USB standard data transfer cannot be performed between peripheral devices. Therefore, the USB On-The-Go (OTG) standard was established. In the OTG standard, USB standard data transfer can be performed between peripheral devices.

  The power supply switching means in the conventional USB OTG device has a normal transfer mode and a charging mode, and only when the charging mode is set, charging from the power master to the power slave or power from the power slave side to the power master side Supply is possible. (For example, refer to Patent Document 1). Specifically, FIG. 8 shows a configuration diagram of a conventional power supply control circuit and a charging method. The power supply control circuit 32 enables the power supply master switching control only when the charging mode is set. The ID detection circuit 35 notifies whether it is a power source master or a power source slave.

  The ID detection circuit 35 determines only the ID terminal level of the USB terminal when the ID invalid instruction by the ID invalid signal is not received, and when the ID terminal level is “H”, the power supply slave and the ID terminal level is “L”. When it is, it notifies the power supply control circuit that it is a power supply master.

When the ID invalid signal is active, the USB terminal ID is not determined, and the value of the power master / slave forced setting signal is validated and notified to the power control circuit.
JP 2003-61256 A (page 5-7, FIG. 1)

  However, in the conventional configuration, since power can be supplied from the power slave side only in the charging mode, the remaining power of the battery on the power slave side is sufficient during data transfer between USB OTG devices. Since the remaining amount of the battery on the power master side is small, there is a problem that the transfer stops during the data transfer.

  In addition, according to the USB OTG standard, the determination of the power master and the power slave is based on the ID terminal level of the USB cable, so the power master and slave cannot be switched after the USB cable is attached. It has become. This is to avoid a power source collision between devices. Therefore, it has been necessary to replace the USB cable in order to switch the power master.

  The present invention solves the above-described conventional problems, and enables switching between a power supply slave and a power supply master without changing a USB cable and avoiding a power supply collision in a mobile device equipped with a USB OTG. It is an object of the present invention to provide a USB OTG device that switches a power supply device even during transfer and does not interrupt transfer during data transfer.

  In order to solve the above-mentioned conventional problems, the portable data transfer control device of the present invention includes a state machine control unit that controls state transition when performing data transfer, a data transfer control unit that controls data transfer, A rechargeable battery unit that stores a battery, a power supply control circuit unit that controls a power supply, a power supply monitor that performs power supply monitoring, and an ID determination circuit unit that determines a cable connection state are provided.

  The state machine control unit of the present invention is an OTG state machine control unit for controlling the OTG, and the ID determination circuit determines that the USB cable is connected.

  In addition, the power monitoring monitor unit of the present invention monitors the remaining amount of the rechargeable battery and notifies the data transfer control unit whether or not the remaining amount satisfies a given threshold value.

  In addition, when the device is an OTG power master, the data transfer control unit of the present invention notifies the power slave side via the USB cable upon notification from the power monitoring monitor unit that the remaining battery level is equal to or less than a given threshold. Inquires about power supply availability and notifies the result to the OTG state machine control unit. When the device is an OTG power supply slave, the power supply availability inquiry from the power supply master is received, and the battery remaining amount notification result from the power monitoring monitor is followed. A response is made and the result is notified to the OTG state machine control unit.

  The ID determination circuit control unit of the present invention uses the ID terminal level of the attached USB cable and the power master switching signal notified from the data transfer control unit. When there is no power master switching notification, the ID terminal is used as the pseudo ID. When the power supply master switching notification is present and the own device is the power supply master, pseudo ID = 1 is output, and when the power supply master switching notification is present and the own device is the power supply slave, pseudo ID = 0 is output. It outputs, and notifies to an OTG state machine control part and a power supply control circuit part.

  The power control circuit unit of the present invention operates as a power master when the pseudo ID signal notified from the ID determination circuit = 0, and uses the power source of the rechargeable battery when the external power source is not used. When the external power supply is used, the external power supply is supplied to the USB VBUS and the rechargeable battery is also charged. When the pseudo ID signal notified from the ID determination circuit = 1, it operates as a power supply slave. When the external power supply is used, the rechargeable battery is charged.

  The OTG state machine control unit according to the present invention is characterized by having a power master switching unit in accordance with a power master switching notification from the data transfer control unit in addition to the OTG state transition control based on the USB OTG standard.

  In addition, the power master switching means according to the present invention enables the new power master to switch between the portable terminals connected by the USB cable after the current power master stops the VBUS supply and the VBUS level is below the threshold. The VBUS collision is avoided by starting the VBUS supply. Further, after the power master switching control of the present invention, the power master switching control is performed while retaining the data transfer and setting contents executed before the switching process. And the processing before the power master switching control is continued after the power master switching.

  The OTG control method of the present invention has a power master switching step in accordance with the power master switching notification in addition to the control of the OTG state transition conforming to the USB OTG standard, and the power master switching step includes a portable device connected by a USB cable. Between the terminals, the current power supply master stops the VBUS supply, and after determining that the VBUS level is equal to or lower than the threshold, the new power supply master starts the VBUS supply to avoid a VBUS collision.

  According to the data transfer control device of the present invention, it is possible to avoid interruption of data transfer due to running out of battery as long as a sufficient battery is accumulated on the power supply slave side even if the battery remaining on the power supply master side device is small. .

  In addition, it is possible to switch the power source master while avoiding the VBUS collision.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram in which USB OTG devices 10 and 20 according to an embodiment of the present invention are connected by a USB cable. The USB OTG devices 10 and 20 are devices having the same configuration.

  In the USB OTG standard, the USB OTG cable has an OTG-specific ID terminal in addition to the D + and D- signal lines for data transfer, the VBUS for power supply, and the Ground line, which is the same as a normal USB cable. The GND and B plugs are not connected.

  Whether the OTG device connected by the cable is a power master or a power slave is determined according to the ID terminal level.

  The USB OTG device 10 includes a power monitoring monitor 11, a power control circuit 12, a rechargeable battery 13, a data transfer control unit 14, an ID determination circuit 15, and an OTG state machine control unit 16.

  When the USB OTG device 10 is not using the external power supply 3, the power supply monitor 11 monitors whether or not the remaining battery level of the rechargeable battery 13 is equal to or greater than a predetermined threshold, and the monitoring result is sent to the data transfer control unit 14. To be notified.

  The data transfer control unit 14 implements USB data transfer control. Based on the battery remaining amount determination result notified from the power monitoring monitor 11, when the own device is a power source master and the remaining battery amount is smaller than the threshold, the power source is requested, and the own device is the power source master and receives the power source switching request. At times, a response to whether or not the power supply can be switched is sent.

  The ID determination circuit 15 is a pseudo signal used in the OTG state machine control unit 16 and the power control circuit 12 based on the level of the ID terminal determined by the USB cable connection and the power master switching signal notified from the data transfer control unit 14. An ID signal is generated.

  In the present invention, the pseudo ID signal is a signal used in place of the ID terminal signal defined in the OTG standard, and is used to determine the power master and the power slave and to control the OTG state machine. This means that the device is a power supply slave, and when it is “L” level, it indicates that the device is a power supply master.

  When the USB cable is attached to the apparatus, the ID determination circuit 15 assigns the signal level input from the ID terminal to the pseudo ID signal. After that, according to the power master switching signal notified from the data transfer control unit 14, when the switching from the power slave to the power master is notified, the pseudo ID signal is switched from “H” to “L”. When notified of switching to, the pseudo ID signal is switched from “L” to “H”.

  By using a pseudo ID signal instead of the ID terminal level fixed by the USB cable connection, it becomes possible to switch between the power master and the power slave without re-inserting / removing the USB cable.

  The OTG state machine control unit 16 performs state management for performing OTG processing. FIG. 7 shows an OTG state machine defined in the USB OTG standard. An OTG device compliant with the OTG standard has an OTG state machine that performs state transition based on state transition conditions such as a data bus connection state and a Vbus level, and controls the state of the device. In the OTG state machine, the a _ *** state is the state of the power supply master device, and the b _ *** state is the state of the power supply slave device. Also, the USB host operates in the a_host or b_host state, and the USB device operates in the a_peripheral or b_peripheral state.

  FIG. 2 shows the state transition of the OTG state machine managed by the OTG state machine control unit 16 in the present invention. In this state machine, the power supply master and the power supply slave are determined not by the ID terminal signal but by the pseudo ID signal generated by the ID determination circuit 15. According to the OTG standard, the switching between the power master device and the power slave device occurs due to the change of the ID signal level, that is, the insertion / extraction of the USB cable, but in any state of the state machine, the a_idle or b_idle state After the transition to, power source master switching is realized.

  In the present invention, when the pseudo ID signal level changes, when the state transition is performed according to the conventional state machine and the switching between the power supply master and the power supply slave is realized, from the * _host state to the * _idle state, from the * _peripheral state to * _idle Transfer data and setting data are reset by a series of state transition processing to the state. Therefore, when power master switching occurs, a new state p_idle is provided for power master switching control in order to enable transition of the power master and power slave from states other than a_idle and b_idle.

  The state transition via p_idle occurs when a data master / power slave switching instruction is received from the data transfer control unit 14 in a data transfer state, that is, in a_host, a_peripheral, b_host, b_peripheral states. When transitioning to the p_idle state, the data transfer is temporarily interrupted and the transfer data, setting data, etc. are retained.

  After the transition from the power master to the power slave, the transition to p_idle, the power control circuit 12 stops the supply of Vbus, confirms that the Vbus level is equal to or lower than a predetermined threshold value, and further supplies the Vbus from the opposite side. When the Vbus level is started and becomes a predetermined threshold value or more, the state transits to the power supply slave side. At this time, if the state before switching is a_host, the state transitions to b_host. If the state before switching is a_peripheral, the state transitions to b_peripheral.

  The opposite device, that is, the switching device side from the power supply slave to the power supply master, continues the Vbus level determination after transitioning to the p_idle state, starts Vbus supply from the time when it falls below a predetermined threshold, and the Vbus level is predetermined. After confirming that the threshold value is exceeded, the state transitions to the power master side. At this time, if the state before switching is b_host, transition to a_host, and if the state before switching is b_peripheral, transition to a_peripheral.

  The power supply control circuit 12 performs power supply control to Vbus based on the pseudo ID notified from the ID determination circuit 15. When the pseudo ID = “L”, power is supplied to Vbus. When the external power source is not used, the power source of the rechargeable battery 13 is used for Vbus supply. When the external power source is used, the external power source is used. In addition, when using an external power supply, the rechargeable battery is charged at the same time.

  FIG. 3 and FIG. 4 show an example of processing when power master switching occurs in the present invention when the power master side is peripheral (device operation) and the power slave side is host (host operation).

  The OTG device 1 and the OTG device 2 are in a state in which a USB cable mini-A plug is attached to the OTG device 1 and a USB cable mini-B plug is attached to the OTG device 2. In the initial state, the OTG device 1 with the mini-A plug inserted operates as a power supply master, and the OTG device 2 with the mini-B plug inserted operates as a power supply slave. FIG. 3 illustrates processing from a state in which the OTG device 1 has transitioned to the a_host and the OTG device 2 has transitioned to the b_peripheral state in accordance with the state transition condition of the OTG state.

  The OTG device 1 on the power source master side determines whether or not there is a state transition condition in the a_host state (step S101) (step S102), and transitions to the corresponding state if the state transition condition occurs. Further, in the a_host state, the remaining battery level is checked (step S103). If the remaining battery (power supply) level is OK, transfer data presence / absence determination is performed (step S104), and if there is transfer data, data transfer is performed. (Step S105) If the remaining battery level is NG in the battery remaining amount check, the data transfer is temporarily stopped (Step S106), and an inquiry is made to the power supply slave side as to whether the power supply can be switched using USB control transfer. . (Step S107) If there is a response of switching OK (in the case of OK in Step S108), a transition to the p_idle state is performed without changing the setting contents such as data. (Step S109) If the switching is NG, the a_host state remains until the state transition condition occurs.

  The OTG device 2 on the power supply slave side determines whether or not there is a state transition condition in the b_peripheral state (step S201) (step S202), and performs transition to the corresponding state if the state transition condition has occurred. In the b_peripheral state, a response to the data transfer from the OTG device 1 is made (from step S203 to step S206). When a power master switching inquiry by control transfer is received (in the case of Y in step S205), the battery (power source) The remaining amount is checked (step S207), and if there is a remaining battery level equal to or greater than a predetermined threshold, it is determined whether or not switching to the power source master is OK (step S208). The transition to the p_idle state is performed. (Step S209) If the switching is NG (in the case of NG in Step S208), the b_peripheral state remains until the state transition condition is generated.

  The OTG device 1 on the power supply master side stops the Vbus supply when it transits to the p_idle state. (Step S110) When the OTG device 2 on the other power supply slave side transits to the p_idle state, it monitors the Vbus level (Step S210) and confirms that the Vbus has become a predetermined threshold value or less, and then supplies the Vbus. Start. (Step S211) This is a measure for causing a device failure due to a power supply collision when Vbus is supplied from both devices.

  The OTG device 1 also monitors the Vbus level (steps S111 and S112). After the Vbus becomes equal to or lower than the predetermined threshold, it is confirmed again that the Vbus becomes equal to or higher than the predetermined threshold, and the state transitions to the b_host state of the power supply slave state. (Step S113) Also, the OTG device 2 confirms that Vbus has become equal to or greater than a predetermined threshold value, and transitions to the a_peripheral state of the power supply master state (step S213). When both devices complete the state transition, the data transfer and the like that were performed before the power master switching processing are continued (the OTG device 1 performs the process of step S114, and the OTG device 2 performs the process of step S214. Process).

  FIG. 5 and FIG. 6 show an example of processing when the power master switching occurs when the power master side is host (host operation) and the power slave side is peripheral (device operation) in the present invention.

  The OTG device 1 and the OTG device 2 are in a state in which a USB cable A plug is attached to the OTG device 1 and a USB cable B plug is attached to the OTG device 2. In the initial state, the OTG device 1 with the A plug inserted operates as a power supply master, and the OTG device 2 with the B plug inserted operates as a power supply slave. 4 and 5 show processing from the state in which the OTG device 1 has transitioned to the a_peripheral (step S301) and the OTG device 2 has transitioned to the b_host state (step S401) in accordance with the state transition condition of the OTG state.

  The OTG device 1 determines the presence / absence of a state transition condition in the a_peripheral state (step S302), and performs transition to the corresponding state if the state transition condition has occurred.

  On the other hand, the OTG device 2 determines whether there is a state transition condition in the b_host state (step S402), and performs a transition to a corresponding state if the state transition condition has occurred.

  When the power master side performs a_peripheral, that is, a device operation, data transfer cannot be performed voluntarily, and therefore a power master switching request cannot be made at its own timing. Therefore, the interrupt request that occurs periodically is used to realize the power master switching request.

  When the OTG device 1 on the power supply master side receives an interrupt transfer from the OTG device 2 in the a_peripheral state (it is determined that there is a transfer in step S303, it is determined that there is no control transfer in the next step S304, and in the subsequent step S305, the interrupt is determined). When it is determined that the battery is transferred, the battery (power supply) remaining amount is checked (step S306), and the response of the remaining battery amount OK / NG is returned to the OTG device 2 (step S307).

  When the OTG device 2 on the power supply slave side receives a response to the power master switching request (meaning remaining battery level NG) from the OTG device 1 by interrupt transfer in the b_host state (Y in step S404), The battery (power) remaining amount is checked (step S405). If there is a battery (power) remaining amount equal to or greater than a predetermined threshold value and switching is OK (in the case of OK in step S407), the power source master is transferred by control transfer. The switching instruction is transferred (step S408), and the transition to the p_idle state is made while maintaining the settings such as data transfer (step S409).

  When the OTG device 1 receives the power master switching instruction by control transfer, the OTG device 1 transits to the p_idle state while maintaining the settings such as data transfer (step S311).

  The OTG device 1 on the power supply master side stops the Vbus supply when it transits to the p_idle state. (Step S312) When the OTG device 2 on the other power supply slave side transitions to the p_idle state, it monitors the Vbus level (Step S410) and confirms that the Vbus has become a predetermined threshold value or less, and then supplies the Vbus. Start. (Step S411) This is a measure for causing a device failure due to a power supply collision when Vbus is supplied from both devices.

  The OTG device 1 also monitors the Vbus level (step S313), confirms that the Vbus is below the predetermined threshold, then receives the VBUS supply and again exceeds the predetermined threshold (step S314), and the power supply slave state Transition to the b_peripheral state. (Step S315) Also, the OTG device 2 confirms that Vbus has become equal to or greater than a predetermined threshold value, and transitions to the a_host state of the power supply master state. When both devices complete the state transition, processing such as data transfer that was executed before the power master switching processing is continued.

(The OTG device 1 performs the process of step S316, and the OTG device 2 performs the process of step S414.)
In the above description, the power master switching method from the state where the OTG device with the A plug inserted is the power master and the OTG device with the B plug inserted is the power slave has been described. The power master switching from the state in which the OTG device into which the A plug is inserted is the power slave and the OTG device into which the B plug is inserted is the power master can be similarly performed.

  Further, the present invention is not limited to a device that extends the USB OTG standard, and can also be applied to a system having a configuration of a power source master and a power source slave.

  The data transfer control device according to the present invention has a power master switching function having means for avoiding a power source collision between devices without losing data being transferred, and is useful as data transfer control between portable terminals. is there.

  This is particularly effective when the USB OTG function is expanded and mounted.

Configuration diagram of an OTG data transfer control device according to Embodiment 1 of the present invention Explanatory drawing which shows the state transition of the OTG state machine in Embodiment 1 of this invention First flow diagram showing an example in which power master switching occurs when the power master side is a peripheral (device operation) and the power slave side is a host (host operation) in the present invention (part 1) FIG. 2 is a second flowchart showing an example in which power master switching occurs when the power master side is peripheral (device operation) and the power slave side is host (host operation) in the present invention. 1 is a first flowchart showing an example in which power master switching occurs when the power master side is host (host operation) and the power slave side is peripheral (device operation) in the present invention. FIG. 11 is a second flowchart showing an example in which power master switching occurs when the power master side is host (host operation) and the power slave side is peripheral (device operation) in the present invention. Explanatory diagram showing state transition of USB OTG standard OTG state machine Configuration diagram of a conventional USB OTG device that realizes power master switching

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 OTG data transfer apparatus 11 Power supply monitoring monitor 12 Power supply control circuit 13 Rechargeable battery 14 Data transfer control part 15 ID determination circuit 16 OTG state machine control part 30 OTG data transfer apparatus which implements conventional power supply master switching 32 Power supply control circuit part 35 ID detection circuit

Claims (10)

A portable data transfer control device,
A state machine control unit that controls state transition when performing data transfer; and
A data transfer control unit for controlling data transfer;
A rechargeable battery for storing the battery;
A power supply control circuit for controlling the power supply;
A power monitoring monitor for power monitoring;
An ID determination circuit for determining a cable connection state;
A data transfer control device. The data transfer control device is a data transfer control device having a USB On-The-Go (OTG) interface,
The state machine control unit is an OTG state machine control unit for controlling the OTG,
The data transfer control device according to claim 1, wherein the ID determination circuit determines whether or not the USB cable is connected. The said power supply monitoring monitor monitors the remaining amount of a rechargeable battery, and notifies whether a remaining amount satisfy | fills a predetermined threshold value to a data transfer control part. Data transfer control device. The data transfer control unit
If the device is an OTG power master, a power supply slave side inquiry is made to the power slave side via a USB cable in response to a notification from the power monitoring monitor that the remaining battery level is below a given threshold, and the result is sent to the OTG Notify the state machine controller
When the device is an OTG power supply slave, a response according to the battery remaining amount notification result from the power supply monitoring monitor is made and a result is notified to the OTG state machine control unit by receiving a power supply availability inquiry from the power supply master. The data transfer control device according to claim 2 or 3, characterized in that The ID determination circuit control unit includes:
Using the ID terminal level of the attached USB cable and the power master switching signal notified from the data transfer control unit,
If there is no power master switching notification, the value of the ID terminal is output as is to the pseudo ID,
If there is a power master switching notification and the own device is a power master, pseudo ID = 1 is output, and if there is a power master switching notification and the own device is a power slave, pseudo ID = 0 is output and the OTG state The data transfer control device according to any one of claims 2 to 4, wherein the data is notified to the machine control unit and the power supply control circuit. The power supply control circuit
When the pseudo ID signal notified from the ID determination circuit = 0, it operates as a power source master,
When the external power supply is not used, use the rechargeable battery power supply and supply power to the USB VBUS.
When using an external power supply, supply the external power supply to the USB VBUS and also charge the rechargeable battery.
When the pseudo ID signal notified from the ID determination circuit = 1, it operates as a power supply slave,
The data transfer control device according to any one of claims 2 to 5, wherein the rechargeable battery is charged when an external power source is used. The OTG state machine control unit
7. The power master switching unit according to the power master switching notification from the data transfer control unit in addition to the OTG state transition control compliant with the USB OTG standard. 8. The data transfer control device according to 1. The power master switching means is between portable terminals connected by a USB cable.
8. The VBUS collision is avoided by starting the VBUS supply after the current power supply master stops the VBUS supply and determines that the VBUS level is below the threshold value. Data transfer control device. Perform power master switching control while retaining the data transfer and settings before power master switching,
9. The data transfer control device according to claim 8, wherein processing before power master switching control is continued after power master switching. In addition to the OTG state transition control compliant with the USB OTG standard, a power master switching step according to the power master switching notification is provided.
In the power master switching step, between portable terminals connected by a USB cable,
A data transfer control method characterized in that a VBUS collision is avoided by starting a VBUS supply by a new power supply master after it is determined that the current power supply master stops the VBUS supply and the VBUS level is equal to or less than a threshold value.

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