Electronic device, control method thereof, and computer readable storage medium

Abstract

An electronic device includes: a communication component capable of selectively using one of the communication methods to communicate with an external device via an interface. The electronic device determines a communication method that cannot be used for communication with the external device from the communication methods through a process for establishing communication with the external device using the communication component. The electronic device displays a user interface in which the determined communication method cannot be selected.

Description

Technical Field

[0001] The invention relates to an electronic device and a control method thereof. Background Art

[0002] It is known that the Alternate Mode enables communication conforming to a standard other than USB (non-USB communication) to be performed using a cable conforming to the USB Type-C standard. Between devices supporting the Alternate Mode, communication conforming to the USB standard and non-USB communication can be switched through a single interface (same cable) (see Patent Document 1). Communication conforming to the DisplayPort (DP) standard (DP communication) is an example of non-USB communication that can be performed using the Alternate Mode.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent document 1: Japanese Patent Laid-Open No. 2018-200345 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In order to communicate in accordance with a specific standard between devices supporting the Alternate Mode, each device needs to have appropriate communication capabilities. For example, for DP communication, two connected devices need to support the DP standard, and one of these devices needs to be able to be used as a source device (output device) according to the DP standard, and the other device needs to be able to be used as a sink device (input device) according to the DP standard. In the case where one of these devices does not support the DP standard, and in the case where both devices can be used as source devices or sink devices, DP communication cannot be performed.

[0008] However, conventional devices supporting alternative modes enable users to select a communication method with a counterpart device based only on their own communication capabilities. Therefore, there are cases where communication with a counterpart device cannot be performed using the communication method selected by the user. In this case, the user does not know that he / she has selected a communication method that cannot be performed until communication with the counterpart device fails. Therefore, there is room for improvement in usability.

[0009] Solutions for solving problems

[0010] According to aspects of the present invention, usability of electronic devices supporting different communication standards can be improved.

[0011] According to aspects of the present invention, there is provided an electronic device comprising: an interface; a display component for displaying a user interface for a user to select a communication method to be used in communicating with an external device via the interface; a communication component capable of selectively using one of the communication methods to communicate with the external device via the interface; and a control component, wherein the control component determines, from among the communication methods, a communication method that cannot be used for communicating with the external device via a process for establishing communication with the external device using the communication component, and the control component displays, on the display component, a user interface in which the determined communication method cannot be selected.

[0012] According to aspects of the present invention, there is provided a control method for an electronic device, the electronic device comprising: an interface; a display component for displaying a user interface, the user interface being used for a user to select a communication method to be used in communicating with an external device via the interface; and a communication component capable of selectively using one of the communication methods to communicate with the external device via the interface, the control method comprising: judging, from among the communication methods, a communication method that cannot be used for communication with the external device through a process for establishing communication with the external device using the communication component; and displaying, on the display component, a user interface in which a communication method cannot be selected, the communication method being a communication method that is judged in the judgment as not being usable for communication with the external device.

[0013] Other aspects of the present invention will become apparent from the embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a block diagram showing an example of the functional configuration of the electronic device 100 according to the first embodiment.

[0015] Figure 2 is a diagram showing a connection configuration of external devices according to the first embodiment.

[0016] Figure 3 is a sequence diagram related to an operation for detecting device connection according to the first embodiment.

[0017] Figure 4 is a sequence diagram related to a procedure for establishing communication in the SS mode according to the first embodiment.

[0018] Figure 5 is a sequence diagram related to a procedure for establishing DP communication according to the first embodiment.

[0019] Fig. 6A is a sequence diagram related to the procedure for establishing USB communication according to the first embodiment.

[0020] Figure 6B is a sequence diagram related to the procedure for establishing USB communication according to the first embodiment.

[0021] Figure 7 is a sequence diagram related to the procedure for switching from USB communication to DP communication according to the first embodiment.

[0022] Fig. 8A is a sequence diagram related to a procedure for establishing DP communication according to the second embodiment.

[0023] Figure 8B is a sequence diagram related to a procedure for establishing DP communication according to the second embodiment.

[0024] Fig. 9 is a sequence diagram related to a procedure for switching from DP communication to USB communication according to the second embodiment.

[0025] Fig. 10A is a sequence diagram related to a process for judging the communication capability of an external device according to the third embodiment.

[0026] Fig. 10B is a sequence diagram related to a process for judging the communication capability of an external device according to the third embodiment. DETAILED DESCRIPTION

[0027] Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0028] Note that in the embodiments described below, an alternative mode according to the USB standard is used as an example of a technology for selectively using one of the communication methods that conform to different standards to communicate with an external device using a single interface or cable. The embodiments described below may be applicable to other technologies that implement the same functions. Note that details of the USB 3.1 standard, USB Type-C standard, and USB PowerDelivery (PD) standard related to the embodiments described below can be found in the corresponding specifications. In addition, in the embodiments described below, a digital camera is used as an example of an electronic device. The electronic device in the embodiments described below may be a computer device such as a personal computer, a smart phone, a tablet terminal, a game console or a media player, a robot, a vehicle, or a household appliance.

[0029] [First embodiment]

[0030] <Configuration of Digital Camera>

[0031] Figure 1is a block diagram showing an example of the functional configuration of the electronic device 100 according to the first embodiment.

[0032] The control unit 101 includes one or more programmable processors. The processor of the control unit 101 uses the ROM 104 to execute the program stored in the non-volatile memory 103 to control the operation of each unit of the electronic device 100 and realize various functions of the electronic device 100. In the following, unless otherwise specified, the operation performed by the control unit 101 will be understood to be implemented by the processor of the control unit 101 for executing the program.

[0033] The bus 130 provides, for connected functional blocks, a communication path to other functional blocks.

[0034] The nonvolatile memory 103 stores programs, various settings or GUI data, etc. executable by the processor of the control unit 101. The ROM 104 is used in the execution of the program by the processor of the control unit 101. The SDRAM 105 is used as a buffer for image data for temporarily storing various information such as management information.

[0035] A media interface (IF) 108 is a communication interface with a storage medium 109. The media IF 108 sends commands to the storage medium 109 and sends or receives data to or from the storage medium 109 according to control of the control unit 101. For example, the storage medium 109 is a memory card.

[0036] The imaging unit 120 includes an imaging optical system (lens), an aperture, a shutter, an image sensor, etc. According to the control of the control unit 101 , the imaging unit 120 performs an imaging operation and stores obtained RAW image data in the SDRAM 105 via the bus 130 .

[0037] The developing unit 121 reads out the RAW image data stored in the SDRAM 105. Then, the developing unit 121 applies a developing process to the read RAW image data. The developing process includes, but is not limited to, a pixel interpolation process, a filtering process, a resizing process, a color conversion process, or a signal format conversion process. The signal format conversion process is, for example, a process for converting from an RGB format to a YCbCr format. The developing unit 121 stores the image data after the developing process in the SDRAM 105.

[0038] The control unit 101 reads the image data after the development process from the SDRAM 105. Then, the control unit 101 stores a data file of a predetermined format storing the read image data in the storage medium 109 via the medium IF 108. The control unit 101 also reads the image data from the data file stored in the storage medium 109 and stores it in the SDRAM 105.

[0039] The display control unit 106 reads the image data after the development process from the SDRAM 105. Then, the display control unit 106 generates image data for display based on the read image data. The display control unit 106 generates image data for display by, for example, applying a scaling process suitable for the resolution of the display unit 107 to the image data. For example, the display control unit 106 outputs the generated image data for display to the display unit 107 which is a touch display.

[0040] The display unit 107 displays an image based on the image data for display generated by the display control unit 106. In addition, the display unit 107 displays a GUI including a menu screen, icons or software keys, etc. The touch panel of the display unit 107 is used as an operation unit for the user to give instructions to the electronic device 100. Note that the electronic device 100 may include other input devices such as switches or buttons, etc., which serve as the operation unit.

[0041] The USB Type-C socket 115 (hereinafter referred to as the Type-C socket 115) is a socket that complies with the USB Type-C standard. The Type-C socket 115 matches the Type-C plug provided on the USB cable or the like. The control unit 101 can communicate with an external device via the Type-C socket 115 using various standards and at various speeds. Controllers 110 to 113 for USB communication and non-USB communication and a disconnection unit 117 are connected to the Type-C socket 115.

[0042] In the case of USB communication with an external device via SuperSpeed ​​(SS) mode, the control unit 101 uses a USB 3.1 controller 111 (hereinafter also referred to as SS 111). In addition, in the case of USB communication with an external device via a speed mode up to USB 2.0 (Non-SuperSpeed ​​(NSS) mode), the control unit 101 uses a USB 2.0 controller 110 (hereinafter also referred to as NSS 110). NSS mode includes a High-Speed ​​mode, a Full-Speed ​​mode, and a Low-Speed ​​mode. In the case of DP communication (i.e., non-USB communication) compliant with the DisplayPort standard with an external device, the control unit 101 uses a display controller 112 (hereinafter also referred to as DP 112).

[0043] According to the control of the switching unit 116 , the PD controller 113 controls the start and stop of the alternative mode according to the sequence set by the USB PD standard.

[0044] The multiplexer (MUX) 114 selectively connects the signal line of the SS 111 or the signal line of the DP 112 to the Type-C socket 115 according to the control of the switching unit 116 .

[0045] The switching unit 116 controls the PD controller 113 and the MUX 114 according to the control of the control unit 101. The control unit 101 communicates with the external device through the switching unit 116, and communicates with the external device through a configuration channel (CC). The switching unit 116 controls switching between USB communication and non-USB communication in the alternative mode.

[0046] The disconnection unit 117 selectively connects to the CC of the USB Type-C socket 115 and disconnects the communication with the external device. The control unit 101 controls the connection of the disconnection unit 117 and the cancellation of the connection.

[0047] The mode acquisition unit 119 controls the PD controller 113 and detects whether the external device supports the DisplayPort standard using a sequence of the USB PD standard.

[0048] <Connection Configuration>

[0049] Figure 2Schematically shows signal lines and channels when the electronic device 100 and the external device 200 are connected via a USB Type-C standard connector. Here, the external device 200 is, for example, a display device that supports DisplayPort over USB-C (or DP Alt mode). The external device 200 includes a Type-C socket 210 that is the same as the Type-C socket 115 of the electronic device 100.

[0050] D+ / D- 201 is used by USB 2.0 controller 110 for USB communication in NSS mode. SS TX / RX 202 is used by USB 3.1 controller for USB communication in SS mode. In alternative mode, SS TX / RX 202 is also used for DP communication using DP controller 112. VBUS 203 is a 5V power line. Configuration channel (CC) 204 is used to detect, set up and manage connections with external devices.

[0051] <Connection Detection>

[0052] According to the USB Type-C standard, for example, when a pull-up resistor Rp or a pull-down resistor Rd is connected to CC1 , CC2 , the connection and / or function of a device is recognized and displayed on the counterpart device.

[0053] Specifically, the pull-up resistor Rp is connected to the CC of the source device, and the pull-down resistor Rd is connected to the CC of the sink device. Note that the source device is a device for detecting a connection, and the sink device is a device whose connection is detected. The specific impedance values ​​of the pull-up resistor Rp and the pull-down resistor Rd are specified in the standard.

[0054] Next, we will use Figure 3 The connection detection sequence of the source device (hereinafter referred to as the source) and the sink device (hereinafter referred to as the sink) is described with reference to a sequence diagram of FIG. In addition, here, the electronic device 100 is the source, and the external device 200 is the sink.

[0055] In step S300 , the control unit 101 controls the USB 2.0 controller 110 and pulls up CC1 and CC2 of the Type-C socket 115 with Rp. In addition, the control unit 101 performs control so that the USB 2.0 controller 110 does not supply power to VBUS of the Type-C socket 115 .

[0056] In step S301 , the external device 200 uses Rd to pull down CC1 and CC2 of the Type-C socket 210 . In addition, since the electronic device 100 is not powered at this time, the power supply at VBUS of the Type-C socket 210 is not detected.

[0057] In step S302, the plug of the USB Type-C cable is inserted into the Type-C sockets 115 and 210 of the electronic device 100 and the external device 200.

[0058] Therefore, in S303, CC1 and CC2 are electrically connected between the electronic device 100 and the external device 200, and CC1 and CC2 of the Type-C socket 115 are connected to the pull-down resistor Rd in the external device 200.

[0059] In step S304, the USB 2.0 controller 110 detects that CC1 and CC2 are being pulled down by Rd, and thereby recognizes that a connection with the host (external device 200) has been made.

[0060] In step S305, the control unit 101 controls the USB 2.0 controller 110 and starts supplying power to VBUS of the Type-C socket 115.

[0061] In step S306, the external device 200 detects the power supply to VBUS of the Type-C socket 210. In this way, the external device 200 recognizes that a connection with the source (electronic device 100) has been made.

[0062] <Connection sequence in SS mode>

[0063] Next, the connection sequence in SS mode according to the USB Type-C standard will be described using Figure 4 the sequence diagram. Additionally, here, the electronic device 100 is the source and the USB host, and the external device 200 is the host and the USB device.

[0064] Figure 4 The processing of steps S400 to S406 of Figure 3 is the same as the processing of steps S300 to S306 of

[0065] and thus its description will be omitted.

[0066] By performing the receiver detection process, both the electronic device 100 and the external device 200 detect the electrical connection with the other device.

[0067] In step S409, the electronic device 100 and the external device 200 perform link initialization processing at the SS link, and in step S410, an SS mode connection is established.

[0068] <DP communication sequence in alternative mode>

[0069] Next, we will use Figure 5 1 is used to describe a non-USB communication (DP Alt mode) connection sequence using an alternative mode between the electronic device 100 and the external device 200. The electronic device 100 is a source, and the external device 200 is a sink.

[0070] The processing of steps S500 to S504 is Figure 3 The processes of steps S300 to S304 are the same, and therefore description thereof will be omitted.

[0071] In step S505, the control unit 101 controls the PD controller 113 and performs negotiation (power negotiation) related to power supply with the external device 200 via the CC. In the negotiation, the control unit 101 and the external device 200 perform a packet start (SOP) communication defined by the USB PD standard. Through the negotiation, the control unit 101 and the external device 200 determine settings related to power supply, such as maximum current, operating current, and VBUS power supply direction. The detailed process of the negotiation is listed in the standard, and a more detailed description is therefore omitted. In addition, in the case where the source or sink does not support negotiation related to power supply, the processing of step S505 can be omitted.

[0072] In step S506, the control unit 101 controls the mode acquisition unit 119 and transmits a Discover SVID command to the external device 200 via CC. The Discover SVID command is a command for acquiring a list of Standard or Vendor IDs supported by the counterpart device.

[0073] In step S507 , the external device 200 sends back a list of supported SVIDs.

[0074] In step S508, the control unit 101 checks whether the DisplayPort VID (FF01h) is in the SVID list received in step S507. In the case where the DisplayPort VID is found, the control unit 101 determines that the external device 200 supports the DisplayPort standard. On the other hand, in the case where the DisplayPort VID is not found in the SVID list received from the external device 200, the control unit 101 determines that the external device does not support the DisplayPort standard and ends the connection process.

[0075] In step S509 , the control unit 101 controls the switch unit 116 , and sends a Discover Modes command designating the DisplayPort VID to the external device 200 .

[0076] In step S510 , the external device 200 sends back a list of modes of the SVID specified in the discovery mode command.

[0077] In step S511 , the control unit 101 controls the switching unit 116 , and transmits an Enter Mode command for designating one mode received in step S510 to the external device 200 .

[0078] In step S512, the external device 200 sends back an acknowledgement message (ACK) for confirming the transition to the designated mode.

[0079] In step S513 , the control unit 101 controls the switch unit 116 , and sets the MUX 114 to a state in which the four signal lines of the DP 112 are connected to the four SS signal lines of the USB Type-C receptacle 115 .

[0080] In step S514, the control unit 101 controls the switching unit 116 and sends a good CRC (GoodCRC) command. The GoodCRC command is a message used to indicate that the immediately preceding message has been successfully received. Therefore, when the external device 200 receives the GoodCRC command sent in step S514, the external device 200 recognizes that the ACK sent in step S512 has been successfully received.

[0081] In step S515, the electronic device 100 and the external device 200 shift to the alternate mode. Hereinafter, communication (DP communication) conforming to the DisplayPort standard is performed between the electronic device 100 and the external device 200.

[0082] Note that the above command is implemented using a message called a Vendor Defined Message (VDM). Specifically, the command represents a value specified in the command field (bit 4..0) of the VDM header included in the VDM. The value of the command is as follows.

[0083] Found SVID=2

[0084] Discovery Mode = 3

[0085] Enter Mode = 4

[0086] The format of the VDM header is listed in the USB PD standard, and thus a more detailed description thereof is omitted.

[0087] The electronic device 100 of the first embodiment supports an alternative mode and is capable of USB communication and DP communication. In addition, in DP communication, the electronic device 100 is used as a source device (output device). When an external device is connected via the Type-C socket 115, the control unit 101 causes the display unit 107 to display a menu screen in which the user selects whether to use USB communication or DP communication with the external device. Then, the control unit 101 performs a process for establishing a connection with the external device using the communication method selected by the user from the menu screen in the communication method.

[0088] In the next example, in the case of establishing communication with an external device using the first communication method (standard), the user gives an instruction to change to the second communication method. The control unit 101 controls the PD controller 113 and the switching unit 116 to perform a mode change or end process of the alternative mode, and attempts to establish communication using the second communication method. However, in some cases, the external device 200 may not support the second communication method. In addition, even if the external device 200 supports the second communication method, if the relationship between the devices (source / sink relationship, USB host / USB device relationship) is not satisfied, communication using the second communication method cannot be established.

[0089] In this case, the communication using the first communication method is disconnected from the time of switching to the second communication method until the communication is reestablished using the first communication method after the connection establishment fails. Therefore, in addition to causing the user to perform unnecessary switching operations, unnecessary communication disconnection and reestablishment are performed. Therefore, there is room for improvement in terms of usability and power consumption reduction.

[0090] For example, in the case where the external device 200 is a display device that supports the DP Alt mode, the external device 200 can use the alternative mode for DP communication, but may not have the USB communication function. This is because the device that supports the alternative mode needs to comply with the USB PD standard, but the data communication function is not mandatory in the USB PD standard. In addition, in the case where the external device is a smart phone or a tablet terminal, even if the external device supports USB communication, it may not support DP communication. In addition, even if the external device 200 supports DP communication, if the external device 200 can only be used as a source device, it is impossible to make the electronic device 100 operate as a source device in DP communication.

[0091] Therefore, in the first embodiment, the options of the communication method that the user can select are changed according to the communication capability of the connected external device. This helps prevent the user from giving unnecessary instructions for switching to the communication method and helps prevent unnecessary processes from being performed. The operations for implementing these operations will be described below.

[0092] <Connection operation with external devices>

[0093] Now refer to Fig. 6A and 6B The sequence diagram describes operations performed when the electronic device 100 according to the first embodiment establishes USB communication with the external device 200.

[0094] In step S600, the plug of the Type-C cable is inserted into the Type-C sockets 115, 210 of the electronic device 100 and the external device 200. When the plug is detected to be inserted into the Type-C socket 115, the control unit 101 controls the display control unit 106 and causes the display unit 107 to display the communication method selection screen 630. The selection screen 630 is a user interface for the user to select a communication method.

[0095] The selection screen 630 includes a USB connection icon 631 for indicating USB communication as a communication method with the external device 200 and a DP connection icon 632 for indicating DP communication. Both the USB connection icon 631 and the DP connection icon 632 serve as software keys. When a touch operation on an area corresponding to an icon is detected on the display unit 107 which is a touch display, the control unit 101 recognizes it as a selection operation on the icon. For example, in the case where the user wants to transfer image data to a PC, the user can select USB communication, and in the case where the user wants to mirror the display of the display unit 107 on an external display device, the user can select DP communication. In the following example, the user selects (touches) the USB connection icon 631, and USB communication is performed.

[0096] In step S601 , the control unit 101 detects that the USB connection icon 631 on the selection screen 630 has been selected.

[0097] In step S602, the control unit 101 controls the connection unit 118 to connect the pull-up resistor Rp to CC1 and CC2 of the Type-C socket 115 in order to indicate to the external device 200 that it is a source (power supply device) according to the USB PD standard. At this time, the control unit 101 does not supply power to VBUS of the Type-C socket 115.

[0098] Furthermore, in order to inform the user that the USB connection process is being processed during the time from step S602 to step S620, the control unit 101 controls the display control unit 106 and causes it to display a processing screen 633 including an icon instead of the selection screen 630. Note that in order to make it obvious that the process is being executed, the control unit 101 may cause the icon on the processing screen 633 to flash.

[0099] In the following example, the external device 200 is a device that supports dual-role-power (DRP) and can be used as a source or a sink. In this case, the external device 200 connects the pull-down resistor Rd and the pull-up resistor Rp alternately to CC1 and CC2 of the Type-C socket 210 at a tDRP period (minimum 50ms to maximum 100ms) (step S603).

[0100] In step S604 , the external device 200 is in a state where the resistor Rd is connected to the Type-C socket 210 .

[0101] In step S605 , the control unit 101 detects the pull-down of the CC, and thereby recognizes that the sink (external device 200 ) has been connected.

[0102] In step S606 , the control unit 101 controls the PD controller 113 in the same manner as in step S505 , and performs negotiation with the external device 200 related to power supply according to the USB PD standard.

[0103] The processing of steps S607 and S608 is the same as the processing of steps S506 and S507. Through this processing, the control unit 101 acquires a list of SVIDs supported by the external device 200.

[0104] In step S609, the control unit 101 determines whether the DisplayPort VID (FF01h) is in the acquired SVID list. Then, the control unit 101 stores the determination result as data related to the communication capability of the external device in the RAM 104. Here, if the DisplayPort VID exists, the control unit 101 determines that the external device 200 is a device that supports DP communication, and if the DisplayPort VID does not exist, the control unit 101 determines that the external device 200 is a device that does not support DP communication.

[0105] The processing from step S602 to step S609 is a process for determining whether DP communication with the external device 200 is possible. In USB communication, the electronic device 100 is used as a device. In addition, the device used as a device in USB communication needs to be used as a sink in USB PD. Therefore, in order to reset the electronic device 100 as a sink, the USB PD process is performed again.

[0106] In step S610 , the control unit 101 connects the disconnection unit 117 to CC1 and CC2 of the Type-C socket 115 and puts CC in a high impedance state (Hi-z). Thus, CC is put in an electrically disconnected state (step S611 ).

[0107] In step S612 , the external device 200 detects the communication disconnection and performs a disconnection process.

[0108] In step S613 , the control unit 101 controls the connection unit 118 , and connects the pull-down resistor Rd to CC1 , CC2 of the Type-C socket 115 in order to indicate that itself is a sink.

[0109] In step S614 , the external device 200 periodically switches the resistor connected to the Type-C socket 210 in the same manner as step S603 .

[0110] At step S615 , the external device 200 detects that CC is pulled down during the time when the resistor Rd is connected to the Type-C socket 210 .

[0111] In step S616 , the external device 200 recognizes that the sink has been connected. Then, the external device 200 fixes the resistor connected to the Type-C socket 210 as the pull-up resistor Rp in order for it to function as a source.

[0112] In the same manner as step S606, step S617 is a negotiation process related to power supply. However, the relationship between the source and the sink is opposite to that in step S606.

[0113] In step S618 , the control unit 101 controls the switch unit 116 and sets the MUX 114 to a state in which the four signal lines of the SS 111 are connected to the four SS signal lines of the USB Type-C receptacle 115 .

[0114] In step S619 , the external device 200 starts to supply power to VBUS of the Type-C socket 210 .

[0115] In step S620, the electronic device 100 and the external device 200 perform USB enumeration. In this process, the external device 200 operates as a USB host, and the electronic device 100 operates as a USB device. Via USB enumeration, the host can communicate with the device.

[0116] In step S621 , a USB connection between the electronic device 100 and the external device 200 is established.

[0117] In step S622, the control unit 101 changes the content displayed on the communication method selection screen to be displayed when the external device 200 is connected, based on the judgment result of step S609 or the list acquired in step S608. Note that the control unit 101 may display the communication method selection screen in response to a user instruction, or may continue to display the selection screen while maintaining the communication after establishing the communication in step S621. In the latter case, the selection screen also serves as a confirmation screen for the currently connected communication method.

[0118] Specifically, the control unit 101 refers to the data related to the communication capability of the external device stored in the RAM 104 when displaying the selection screen. Then, the control unit 101 changes the content of the selection screen so as not to display the communication method that the external device 200 does not support (or the communication method that cannot be performed with the external device 200) on the display unit 107.

[0119] The selection screen 635 displayed when DP communication with the external device 200 is possible includes a USB icon 634 as an example of information indicating a currently established communication method and a DP connection icon 632 for instructing switching to DP communication. The selection screen 636 displayed when DP communication with the external device 200 is not possible includes the USB icon 634 but does not include the DP connection icon 632.

[0120] Note that the case where DP communication cannot be performed includes the case where the external device 200 does not support the DisplayPort standard and the case where the external device 200 can only be used as a source. In the case where the external device 200 can only be used as a source, in step S603, the CC of the Type-C socket 210 is pulled up. Therefore, the control unit 101 cannot detect that the CC of the Type-C socket 115 is pulled down in step S605. Therefore, in the case where the control unit 101 cannot detect that the CC is being pulled down after a certain amount of time (for example, 5 seconds) has passed since the CC of the Type-C socket 115 was pulled up in step S602, the control unit 101 determines that the external device 200 is a device that does not support DP communication. Then, the process enters step S609, and the judgment result is stored in the RAM 104 as data related to the communication capability of the external device. In this way, even in the case where the external device 200 can only be used as a source, the process can be performed in the same manner as the case where the external device 200 does not support DP communication.

[0121] Note that even in the case where it is detected that the user selects the DP connection icon 632 in step S601, the control unit 101 performs steps S602 to S609. In addition, in the case where it is determined that the external device 200 cannot perform DP communication, the control unit 101 controls the display control unit 106, for example, and causes the display unit 107 to display a screen 638. The screen 638 includes an error message for notifying the user that the external device cannot communicate using the selected communication method, and an icon for selecting another communication method. Here, since the external device 200 cannot perform DP communication, the USB connection icon 631 is displayed.

[0122] However, in the case where the external device 200 is capable of DP communication, the control unit 101 performs an operation for switching to the alternative mode in order to perform DP communication after step S609. Figure 5 The switching operation is performed in the same manner as steps S509 to S514.

[0123] <Operation for switching from USB communication to non-USB communication>

[0124] Next, we will use Figure 7 The sequence diagram shown is used to describe operations performed when the communication method between the electronic device 100 and the external device 200 is switched from USB communication to non-USB communication (DP communication in this example). Figure 7 The electronic device 100 and the external device 200 have been Fig. 6A and 6B The sequence shown corresponds to the operations performed after USB communications are established.

[0125] When a display instruction of the communication method selection screen is detected during establishment of USB communication, the control unit 101 controls the display control unit 106 and causes it to display the communication method selection screen on the display unit 107. In this example, it has been confirmed that the external device 200 is capable of DP communication before establishing USB communication. In this case, the control unit 101 controls the display control unit 106 to display the communication method selection screen on the display unit 107. Figure 6B The selection screen 635 shown is displayed on the display unit 107 .

[0126] In step S700 , the control unit 101 detects that the DP connection icon 632 on the selection screen 635 has been selected.

[0127] In step S701, the control unit 101 connects the disconnection unit 117 to CC1 and CC2 of the Type-C socket 115, and puts CC in a high impedance state (Hi-z). Thus, CC is put in an electrically disconnected state (step S702).

[0128] Furthermore, in order to inform the user that the DP connection process is being processed during the time from step S701 to step S709, the control unit 101 controls the display control unit 106 and causes it to display a processing screen 722 including an icon instead of the selection screen 635. Note that in order to make it obvious that the process is being executed, the control unit 101 may cause the icon on the processing screen 722 to flash.

[0129] In step S703 , the external device 200 detects the USB communication disconnection and performs a disconnection process.

[0130] In step S704 , the control unit 101 controls the connection unit 118 to connect the pull-up resistor Rp to CC1 and CC2 of the Type-C socket 115 in order to indicate that it is a source. At this time, the control unit 101 does not supply power to VBUS of the Type-C socket 115 .

[0131] In step S705 , the external device 200 periodically switches the resistor connected to the Type-C socket 210 in the same manner as step S603 .

[0132] In step S706 , the external device 200 is in a state where the resistor Rp is connected to the Type-C socket 210 .

[0133] In step S707 , the control unit 101 detects the pull-down of the CC, and thereby recognizes that the sink (external device 200 ) has been connected.

[0134] In step S708 , the control unit 101 controls the PD controller 113 in the same manner as in step S505 , and performs negotiation with the external device 200 related to power supply according to the USB PD standard.

[0135] In step S709, the control unit 101 exchanges messages with the external device 200 and shifts to the alternative mode for DP communication. Figure 5 The operations described in steps S509 to S514 are the same as those described in steps S509 to S514, and thus a description thereof is omitted.

[0136] In step S710, the control unit 101 controls the DP 112 and starts DP communication using the SS signal.

[0137] Furthermore, in the case where DP communication is enabled in step S709, the control unit 101 controls the display control unit 106 and can cause a communication method selection screen 723 to be displayed on the display unit 107. The selection screen 723 includes a DP icon 724 as an example of information indicating a currently established communication method and a USB connection icon 631 for instructing switching to USB communication.

[0138] Note that in step S700, in a case such as when data is currently being transferred between the electronic device 100 and the external device 200 via USB communication, the USB communication disconnection may not be desired. In this case, the control unit 101 may not display the DP connection icon 721 together with the communication method selection screen 635 (or make the DP connection icon 721 displayed together with the selection screen 635 unselectable). Thereafter, when data transfer is completed or in other such states where the USB communication may be disconnected, the control unit 101 displays the DP connection icon 721 together with the selection screen 635, or makes the DP connection icon 721 displayed together with the selection screen 635 selectable.

[0139] According to the first embodiment, using an electronic device that can selectively perform communication that conforms to a standard different from that of an external device using a single interface, before starting communication that conforms to a first standard with an external device, it is checked whether communication that conforms to a second standard is possible. Then, the display of a communication method selection screen is changed based on the check result so that communication methods that cannot be performed are not selectable. This prevents the user from selecting a communication method that cannot be performed by the currently connected external device, thereby improving the usability of the electronic device. In addition, since unnecessary disconnection and reconnection of the currently established connection is avoided, interruption of communication and waste of power consumption can be minimized or prevented.

[0140] Note that in the above-described first embodiment, the electronic device functions as a USB device and can be connected to an external device that functions as a USB host. However, the first embodiment can also be applied to an electronic device that operates as a USB host.

[0141] In addition, in the above-mentioned first embodiment, the non-USB communication performed in the alternative mode is DP communication that complies with the DisplayPort standard. However, the first embodiment does not depend on the type of non-USB communication. For example, non-USB communication that complies with another standard such as HDMI (registered trademark) can be performed with an external device.

[0142] [Second embodiment]

[0143] Next, the second embodiment will be described. The second embodiment can be implemented using the electronic device 100 and the external device 200 in the same manner as the first embodiment, and therefore the description of the common configuration and operation is omitted. In the first embodiment, for the case where an instruction to perform USB communication is received during the effective period of the connection with the external device, it is checked whether DP communication with the external device is possible before establishing USB communication. In the second embodiment, for the case where an instruction to perform DP communication is received during the effective period of the connection with the external device, it is checked whether USB communication with the external device is possible before establishing DP communication.

[0144] <Connection operation with external devices>

[0145] Now refer to Fig. 8A and 8B The sequence diagram describes operations performed when the electronic device 100 according to the second embodiment establishes DP communication with the external device 200.

[0146] In step S800, the plug of the Type-C cable is inserted into the Type-C sockets 115, 210 of the electronic device 100 and the external device 200. When the plug is detected to be inserted into the Type-C socket 115, the control unit 101 controls the display control unit 106 and causes the display unit 107 to display the communication method selection screen 630. The selection screen 630 includes a USB connection icon 631 for indicating USB communication as a communication method with the external device 200 and a DP connection icon 632 for indicating DP communication.

[0147] In step S801 , the control unit 101 detects that the DP connection icon 632 on the selection screen 630 has been selected.

[0148] In step S802 , the control unit 101 controls the connection unit 118 , and connects the pull-down resistor Rd to CC1 , CC2 of the Type-C socket 115 in order to indicate to the external device 200 that it is a sink according to the USB PD standard.

[0149] Furthermore, in order to inform the user that the DP connection processing is in progress during the time from step S802 to step S819, the control unit 101 controls the display control unit 106 and causes it to display a processing screen 722 including a DP icon 724 instead of the selection screen 630. Note that in order to make it apparent that the processing is being executed, the control unit 101 may cause the DP icon 724 on the processing screen 722 to flash.

[0150] In step S803 , the external device 200 connects the pull-down resistor Rd and the pull-up resistor Rp to CC1 and CC2 of the Type-C socket 210 alternately at a tDRP period (minimum 50 ms to maximum 100 ms).

[0151] In step S804 , during the time when the resistor Rp is connected to the Type-C socket 210 at the external device 200 , CC is being pulled down at the electronic device 100 .

[0152] In step S805 , the external device 200 detects the pull-down of the CC, and thereby recognizes that the sink (electronic device 100 ) has been connected.

[0153] In step S806, the external device 200 performs negotiation related to power supply according to the USB PD standard with the electronic device 100. This process is the same as the process performed by the control unit 101 in step S505. Through this negotiation, settings related to power supply between the external device 200 and the electronic device 100 are confirmed.

[0154] In step S807 , the control unit 101 controls the switch unit 116 , and sets the MUX 114 to a state in which the four signal lines of the SS 111 are connected to the four SS signal lines of the USB Type-C receptacle 115 .

[0155] In step S808 , the external device 200 starts to supply power to VBUS of the Type-C socket 210 .

[0156] In step S809, the electronic device 100 and the external device 200 perform USB enumeration. In this process, the external device 200 operates as a USB host, and the electronic device 100 operates as a USB device.

[0157] In step S810, the control unit 101 determines whether the external device 200 is operating as a USB host. Then, the control unit 101 stores the determination result in the RAM 104 as data related to the communication capability of the external device. For example, in the case where the external device 200 is properly communicating as a USB host in the USB enumeration of step S809, the control unit 101 determines that the external device 200 is operating as a USB host. In addition, for example, the control unit 101 can determine that the external device 200 is operating as a USB host based on receiving a specific command (e.g., a GetDescriptor command) from the external device 200.

[0158] Note that in the case where the external device 200 is only capable of serving as a sink, the CC is pulled down in step S803. Therefore, the external device 200 cannot detect the pull-down of the CC in step S805. Therefore, in the case where the control unit 101 cannot start the power supply negotiation after a certain amount of time (e.g., 5 seconds) has passed since the CC was pulled up in step S802, the control unit 101 determines that the external device 200 is a device that does not support USB communication. Then, the process proceeds to step S810, and the control unit 101 stores the determination result in the RAM 104 as data related to the communication capability of the external device. In this way, even in the case where the external device 200 is only capable of serving as a sink, the process can be performed in the same manner as in the case where the external device 200 does not support USB communication.

[0159] The process from step S802 to step S810 is a process for determining whether the external device 200 has a USB communication function (whether USB communication with the external device 200 is possible). Therefore, when this determination is completed, the control unit 101 re-executes the USB PD process for starting DP communication.

[0160] In step S811, the control unit 101 connects the disconnection unit 117 to CC1 and CC2 of the Type-C socket 115, and puts CC in a high impedance state (Hi-z). Thus, CC is put in an electrically disconnected state (step S812).

[0161] In step S813 , the external device 200 detects the communication disconnection and performs a disconnection process.

[0162] In step S814, the control unit 101 controls the connection unit 118, and in order to indicate that it is a source, connects the pull-up resistor Rp to CC1 and CC2 of the Type-C socket 115. At this time, the control unit 101 does not supply power to VBUS.

[0163] In step S815 , the external device 200 periodically switches the resistor connected to the Type-C socket 210 in the same manner as step S803 .

[0164] In step S816 , the external device 200 is in a state where the pull-down resistor Rd is connected to the Type-C socket 210 .

[0165] In step S817 , the control unit 101 detects the pull-down of the CC, and thereby recognizes that the sink (external device 200 ) has been connected.

[0166] In step S818, the control unit 101 controls the PD controller 113 in the same manner as step S505, and performs negotiation related to power supply according to the USB PD standard with the external device 200. Through the negotiation, settings related to power supply between the electronic device 100 and the external device 200 are confirmed.

[0167] In step S819, the control unit 101 exchanges messages with the external device 200 and shifts to the alternative mode for DP communication. Figure 5 The operations described in steps S509 to S514 are the same as those described in steps S509 to S514, and thus a description thereof is omitted.

[0168] In step S820, the control unit 101 controls the DP 112 and starts DP communication using the SS signal.

[0169] In step S821, the control unit 101 changes the content displayed on the communication method selection screen to be displayed when the external device 200 is connected based on the judgment result of step S810. Note that the control unit 101 may display the communication method selection screen in response to a user instruction, or may continue to display the selection screen while maintaining the communication after establishing the communication in step S820. In the latter case, the selection screen also serves as a confirmation screen for the currently connected communication method.

[0170] Specifically, the control unit 101 refers to the information of the communication method not supported by the external device stored in the RAM 104 when displaying the selection screen. Then, the control unit 101 changes the content of the selection screen so as not to display the communication method not supported by the external device 200 (or the communication method that cannot be performed with the external device 200) on the display unit 107.

[0171] The selection screen 723 displayed when the external device 200 is capable of USB communication includes the DP icon 724 as an example of information indicating the currently established communication method, and the USB connection icon 631 for instructing switching to DP communication. The selection screen 834 displayed when the external device 200 is not capable of USB communication includes the DP icon 724 but does not include the USB connection icon 631.

[0172] Note that even in the case where it is detected in step S801 that the user selects the USB connection icon 631, the control unit 101 performs steps S802 to S810. In addition, in the case where it is determined that the external device 200 cannot perform USB communication, the control unit 101 controls the display control unit 106, for example, and causes the display unit 107 to display a screen 837. The screen 837 includes an error message for notifying the user that the external device cannot communicate using the selected communication method, and an icon for selecting another communication method. Here, since the external device 200 cannot perform USB communication, the screen 837 includes the DP connection icon 632.

[0173] However, if the external device 200 is capable of USB communication, after step S810, the process proceeds to Fig. 9 The control unit 101 establishes USB communication without disconnecting the communication at step S912.

[0174] <Operation for switching from non-USB communication to USB communication>

[0175] Next, we will use Fig. 9 The sequence diagram shown is used to describe operations performed when the communication method between the electronic device 100 and the external device 200 is switched from non-USB communication (DP communication in this example) to USB communication. Fig. 9 The electronic device 100 and the external device 200 are connected via Fig. 8A and 8B The sequence shown corresponds to the operations performed after DP communication is established.

[0176] When a display instruction of the communication method selection screen is detected during the establishment of DP communication, the control unit 101 causes the display control unit 106 to display the communication method selection screen on the display unit 107. In this example, it has been confirmed that the external device 200 is capable of USB communication before the establishment of DP communication. In this case, the control unit 101 causes the display control unit 106 to display the communication method selection screen on the display unit 107. Figure 8B The selection screen 723 shown is displayed on the display unit 107 .

[0177] In step S900 , the control unit 101 detects that the USB connection icon 631 on the selection screen 635 has been selected.

[0178] In step S901, the control unit 101 connects the disconnection unit 117 to CC1 and CC2 of the Type-C socket 115, and puts CC in a high impedance state (Hi-z). Thus, CC is put in an electrically disconnected state (step S902).

[0179] Furthermore, in order to inform the user that the USB connection process is being processed during the time from step S901 to step S911, the control unit 101 controls the display control unit 106 and causes it to display a processing screen 633 including a USB icon 634 instead of the selection screen 723. Note that in order to make it obvious that the process is being executed, the control unit 101 may cause the USB icon 634 on the processing screen 633 to flash.

[0180] In step S903 , the external device 200 detects the USB communication disconnection and performs a disconnection process.

[0181] In step S904 , the control unit 101 controls the connection unit 118 , and connects the pull-down resistor Rd to CC1 , CC2 of the Type-C socket 115 in order to indicate that the self is a sink.

[0182] In step S905 , the external device 200 periodically switches the resistor connected to the Type-C socket 210 in the same manner as step S803 .

[0183] In step S906 , the external device 200 is in a state where the pull-up resistor Rp is connected to the Type-C socket 210 .

[0184] In step S907 , the external device 200 detects the pull-down of the CC, and thereby recognizes that the sink (electronic device 100 ) has been connected.

[0185] In step S908 , the external device 200 performs negotiation related to power supply according to the USB PD standard with the electronic device 100 in the same manner as step S806 .

[0186] In step S909 , the control unit 101 controls the switch unit 116 and sets the MUX 114 to a state in which the four signal lines of the SS 111 are connected to the four SS signal lines of the USB Type-C receptacle 115 .

[0187] In step S909 , the control unit 101 controls the switch unit 116 and connects the SS signal line of the USB Type-C socket 115 and the signal line of the SS 111 at the MUX 114 .

[0188] In step S910 , the external device 200 starts supplying power to VBUS.

[0189] In step S911, the electronic device 100 and the external device 200 perform USB enumeration. In this process, the external device 200 operates as a USB host, and the electronic device 100 operates as a USB device. In step S912, USB communication between the electronic device 100 and the external device 200 is established.

[0190] Furthermore, in the case where USB communication is enabled in step S912, the control unit 101 controls the display control unit 106 and may cause the communication method selection screen 635 to be displayed on the display unit 107. The selection screen 635 includes a USB icon 634 as an example of information indicating a currently established communication method, and a DP connection icon 632 for instructing switching to DP communication.

[0191] As described above, the second embodiment can obtain the same effects as the first embodiment. Note that in the second embodiment, the electronic device is connected to an external device that complies with the DisplayPort standard. However, the electronic device according to the second embodiment can also be connected to an external device that complies with another standard.

[0192] In addition, in the above-mentioned second embodiment, the non-USB communication performed in the alternative mode is DP communication that complies with the DisplayPort standard. However, the second embodiment does not depend on the type of non-USB communication. For example, non-USB communication that complies with another standard such as HDMI (registered trademark) can be performed with an external device.

[0193] [Third embodiment]

[0194] Next, the third embodiment will be described. The third embodiment can be implemented using the electronic device 100 and the external device 200 in the same manner as the first embodiment, and therefore the description of the common configuration and operation is omitted. In the first and second embodiments, for the case where an instruction to perform USB / DP communication is received during the effective period of the connection with the external device, it is checked whether DP / USB communication with the external device is possible before establishing USB / DP communication. In the third embodiment, the communication capability of the external device 200 is checked in advance, and a communication method selection screen reflecting the communication capability of the external device 200 is displayed from the beginning.

[0195] <Operation for checking communication capability when connected with an external device>

[0196] Fig. 10A and 10B It is a sequence diagram related to an operation for checking the communication capability of the external device 200 when connected with the external device 200 via a USB Type-C cable.

[0197] In step S1000, the plugs of the Type-C cables are inserted into the Type-C receptacles 115, 210 of the electronic device 100 and the external device 200. At this time, as shown in 1030, the control unit 101 does not cause the display unit 107 to display the communication method selection screen.

[0198] In step S1001 , the control unit 101 controls the connection unit 118 to connect the pull-up resistor Rp to CC1 and CC2 of the Type-C socket 115 in order to indicate that the control unit 101 is a source.

[0199] In step S1002 , the external device 200 connects the pull-down resistor Rd and the pull-up resistor Rp to CC1 and CC2 of the Type-C socket 210 alternately at a tDRP period (minimum 50 ms to maximum 100 ms).

[0200] In step S1003 , the external device 200 is in a state where the resistor Rd is connected to the Type-C socket 210 .

[0201] In step S1004 , the control unit 101 detects the pull-down of the CC, and thereby recognizes that the sink (external device 200 ) has been connected.

[0202] In step S1005, the control unit 101 performs negotiation related to power supply according to the USB PD standard with the external device 200 in the same manner as step S505. Through the negotiation, settings related to power supply between the external device 200 and the electronic device 100 are confirmed.

[0203] In step S1006 , the control unit 101 controls the mode acquisition unit 119 and transmits a discover SVID command to the external device 200 via the CC.

[0204] In step S1007 , the external device 200 sends back a list of supported SVIDs.

[0205] In step S1008, the control unit 101 checks whether the DisplayPort VID (FF01h) is in the SVID list received in step S1007. In the case where the DisplayPort VID is found, the control unit 101 determines that the external device 200 supports the DisplayPort standard. Then, the control unit 101 stores the determination result in the random access RAM 104 as data related to the communication capability of the external device.

[0206] In step S1009, the control unit 101 connects the disconnection unit 117 to CC1 and CC2 of the Type-C socket 115, and puts CC in a high impedance state (Hi-z). Thus, CC is put in an electrically disconnected state (step S1010).

[0207] In step S1011 , the external device 200 detects communication disconnection and performs disconnection processing.

[0208] In step S1012 , the control unit 101 controls the connection unit 118 , and connects the pull-down resistor Rd to CC1 , CC2 of the Type-C socket 115 in order to indicate that the self is a sink.

[0209] In step S1013 , the external device 200 periodically switches the resistor connected to the Type-C socket 210 in the same manner as step S1002 .

[0210] In step S1014 , the electronic device 100 is in a state where the resistor Rd is connected to the Type-C socket 115 .

[0211] In step S1015 , the external device 200 detects the pull-down of the CC, and thereby recognizes that the sink (electronic device 100 ) has been connected.

[0212] In step S1016 , the external device 200 performs negotiation related to power supply according to the USB PD standard with the electronic device 100 in the same manner as the control unit 101 in step S1005 .

[0213] In step S1017 , the control unit 101 controls the switch unit 116 , and connects the SS signal line of the USB Type-C receptacle 115 and the signal line of the SS 111 at the MUX 114 .

[0214] In step S1018 , the external device 200 starts supplying power to VBUS.

[0215] In step S1019, the electronic device 100 and the external device 200 perform USB enumeration. In this process, the external device 200 operates as a USB host, and the electronic device 100 operates as a USB device.

[0216] In step S1020, the control unit 101 determines whether the external device 200 is operating as a USB host in the same manner as step S810. The control unit 101 then stores the determination result in the RAM 104 as data related to the communication capability of the external device.

[0217] In step S1021, the control unit 101 connects the disconnection unit 117 to CC1 and CC2 of the Type-C socket 115, and puts CC in a high impedance state (Hi-z). Thus, CC is put in an electrically disconnected state (step S1022).

[0218] In step S1023 , the external device 200 detects the communication disconnection and performs a disconnection process.

[0219] In step S1024, the control unit 101 controls the display control unit 106 to display the communication method selection screen on the display unit 107, and waits for the user's instruction via the selection screen. Here, the control unit 101 causes the displayed selection screen to include the content according to the judgment results of steps S1008 and S1020. Specifically, the control unit 101 refers to the information related to the communication capability of the external device 200 stored in the RAM 104. Then, the control unit 101 causes the content of the selection screen to not display the communication method that the external device 200 does not support (or the communication method that cannot be performed with the external device 200) on the display unit 107.

[0220] In the following example, the external device 200 is judged as a device capable of USB communication but not capable of DP communication according to the judgment result stored in the RAM 104. In this case, for example, the control unit 101 causes the selection screen 1031 including the USB connection icon 631 but not the DP connection icon to be displayed. Alternatively, the control unit 101 causes the selection screen including the USB connection icon 631 in a selectable state and the DP connection icon in a non-selectable state to be displayed.

[0221] In the next example, the external device 200 is judged as a device capable of DP communication but not USB communication according to the judgment result stored in the RAM 104. In this case, for example, the control unit 101 causes the selection screen 1031 including the DP connection icon 632 but not the USB connection icon to be displayed. Alternatively, the control unit 101 causes the selection screen including the DP connection icon 632 in a selectable state and the USB connection icon in a non-selectable state to be displayed.

[0222] In the next example, the external device 200 is determined as a device capable of both USB communication and DP communication according to the determination result stored in the RAM 104. In this case, the control unit 101 causes a selection screen 630 including a USB connection icon 631 and a DP connection icon 632 to be displayed, for example.

[0223] When the control unit 101 detects that the user has selected the USB connection icon 631, the control unit 101 executes Figure 6B Steps S613 to S621 are performed and USB communication is established.

[0224] When the control unit 101 detects that the user has selected the DP connection icon 632, the control unit 101 executes Figure 7 Steps S704 to S710 are performed and DP communication is established.

[0225] Note that Fig. 10A and10B In the example of FIG. 1 , the external device 200 supports DRP according to the USB PD standard. However, the third embodiment can still be implemented in the case where the external device 200 does not support DRP.

[0226] For example, in the case where the external device 200 is only capable of being used as a source, the CC is pulled up in step S1002. Therefore, in step S1004, the control unit 101 cannot detect the pull-down of the CC. Therefore, in the case where the control unit 101 cannot detect that the CC is being pulled down after a certain amount of time (for example, 5 seconds) has passed in step S1004, the control unit 101 determines that the external device 200 is a device that does not support DP communication. In this way, even in the case where the external device 200 is only capable of being used as a source, processing can be performed in the same manner as in the case where the external device 200 does not support DP communication.

[0227] In addition, in the case where the external device 200 is only capable of serving as a sink, the CC is pulled down in step S1013. Therefore, in step S1015, the external device 200 cannot detect the pull-down of the CC. Therefore, in the case where the control unit 101 cannot start the power supply negotiation after a certain amount of time (e.g., 5 seconds) has passed since the CC was pulled up in step S1012, the control unit 101 determines that the external device 200 is a device that does not support USB communication. Then, the process proceeds to step S1020, and the control unit 101 stores the determination result in the RAM 104 as data related to the communication capability of the external device. In this way, even in the case where the external device 200 is only capable of serving as a sink, the process can be performed in the same manner as in the case where the external device 200 does not support USB communication.

[0228] As described above, the third embodiment can obtain the same effects as the first and second embodiments. In addition, in the third embodiment, when the communication method selection screen is initially displayed, the communication capability of the external device is reflected in the selection screen. Compared with the first and second embodiments, this also helps prevent the user from selecting a communication method that cannot be performed with the external device.

[0229] Note that in the third embodiment, the electronic device includes a USB host function or is connected to an external device that complies with the DisplayPort standard. However, the electronic device according to the third embodiment may be connected to an external device that complies with another standard.

[0230] In addition, in the third embodiment described above, the non-USB communication performed in the alternative mode is DP communication that complies with the DisplayPort standard. However, the third embodiment does not depend on the type of non-USB communication. For example, non-USB communication that complies with another standard such as HDMI (registered trademark) can be performed with an external device.

[0231] [Fourth embodiment]

[0232] The various functions, processes or methods described in the first to third embodiments can be implemented using a program by a personal computer, a microcomputer, a central processing unit (CPU) or a processor, etc. Hereinafter, in the fourth embodiment, the personal computer, the microcomputer, the CPU or the processor, etc. is referred to as "computer X". In addition, in the fourth embodiment, a program for controlling the computer X and for implementing the various functions, processes or methods described in the first to third embodiments is referred to as "program Y".

[0233] The various functions, processes or methods described in the first to third embodiments are implemented by computer X executing program Y, in which case program Y is provided to computer X via a computer-readable storage medium. The computer-readable storage medium of the fourth embodiment includes at least one of the following items: a hard disk device, a magnetic storage device, an optical storage device, a magneto-optical storage device, a memory card, a volatile memory, or a non-volatile memory, etc. The computer-readable storage medium of the fourth embodiment is a non-transitory storage medium.

[0234] An aspect of the present invention has been described using the above-described embodiments. However, aspects of the present invention will be understood to be not limited to the above-described embodiments. The appended scope will be interpreted and understood in the broadest sense to include all variations and equivalent configurations. Therefore, the appended claims are proposed in order to disclose the scope of this specification to the public.

Claims

1. An electronic device, characterized in that include: interface; a display component for displaying a user interface for a user to select a communication method to be used in communicating with an external device via the interface; a communication component capable of selectively using one of the communication methods to communicate with an external device via the interface; as well as Control components, The control component performs the following processing: upon detecting that a user has selected a communication method from the user interface, causing the communication section to execute a process for establishing communication using a communication method other than the communication method selected by the user among the communication methods, before executing a process for establishing communication using the communication method selected by the user, and determining a communication method that cannot be used for communication with the external device, After determining that the communication method cannot be used for communication with the external device, starting a process for establishing communication with the external device using the communication method selected by the user, in a state where communication using the communication method selected by the user is established, displaying a user interface in which the determined communication method cannot be selected on the display means, and in a state where communication using the communication method selected by the user is established, in a case where it is detected that the user has selected another communication method from the user interface, starting a process for establishing communication using the other communication method selected by the user, Wherein, in a case where the external device does not include a necessary function for communicating with the electronic device using a communication method supported by the external device, the control unit determines that the communication method is a communication method that cannot be used for communicating with the external device.

2. The electronic device according to claim 1, wherein: The control section determines a communication method that is not supported by the external device as a communication method that cannot be used for communication with the external device.

3. The electronic device according to claim 1, wherein: In a case where a communication method requires the electronic device and the external device to perform different functions and the electronic device and the external device cannot perform the different functions, the control section determines the communication method as a communication method that cannot be used for communication with the external device.

4. The electronic device according to claim 1, wherein: In a case where both the electronic device and the external device function only as a source device or a sink device according to the USB PD standard, the control section determines a communication method using the USB PD standard as a communication method that cannot be used for communication with the external device.

5. The electronic device according to claim 4, wherein: The communication method using the USB PD standard is communication compliant with the DisplayPort standard.

6. The electronic device according to claim 1, wherein: In a case where both the electronic device and the external device function only as a USB host or a USB device, the control section determines that USB communication is a communication method that cannot be used for communication with the external device.

7. A control method for an electronic device, the electronic device comprising: interface; a display component for displaying a user interface for a user to select a communication method to be used in communicating with an external device via the interface; and a communication component capable of selectively using one of the communication methods to communicate with an external device via the interface, the control method being characterized by comprising: upon detecting that a user has selected a communication method from the user interface, before executing a process for establishing communication using the communication method selected by the user, executing a process for establishing communication using a communication method other than the communication method selected by the user among the communication methods, and determining a communication method that cannot be used for communication with the external device; After determining that the communication method cannot be used for communication with the external device, starting a process for establishing communication with the external device using the communication method selected by the user; in a state where communication using the communication method selected by the user is established, displaying a user interface in which the determined communication method cannot be selected on the display means, and in a state where communication using the communication method selected by the user is established, in a case where it is detected that the user has selected another communication method from the user interface, starting a process for establishing communication using the other communication method selected by the user, Wherein, in the judgment, when the external device does not include a necessary function for communicating with the electronic device using a communication method supported by the external device, the communication method is judged as a communication method that cannot be used for communicating with the external device.

8. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the control method according to claim 7.

Images