PATENT DOCUMENT

Publication Number: US-8238893-B2
Application Number: US-55385009-A
Country: US
Kind Code: B2

Title: Techniques for controlling a portable media device having a radio frequency tuner

Abstract:
Techniques for facilitating interoperation between a portable media device having an RF tuner and an accessory device. In certain embodiments, the portable media device and the accessory can exchange various commands pertaining to the capabilities, state, and/or operation of the tuner. For example, in one set of embodiments the accessory can send one or more commands requesting information about the capabilities of the tuner, and the portable media device can provide the requested capability information. In another set of embodiments, the accessory can send one or more commands requesting execution of a particular action with respect to the tuner, and the portable media device can perform the requested action. In this manner, certain embodiments of the present invention enable a user to control the tuner functionality of the portable media device via the accessory, rather than, e.g., via an input interface located directly on the portable media device.

Claims:
1. A method comprising:
 sending, by an accessory, one or more first commands to a portable media device, wherein the portable media device includes a tuner configured to tune radio frequency signals, and wherein the one or more first commands request tuner capability information indicating one or more capabilities of the tuner, the tuner capability information including at least one of types of bands the tuner supports, resolution the tuner supports for each band, types of controls the tuner supports, or types of modes the tuner supports; 
 receiving, by the accessory, one or more second commands from the portable media device, the one or more second commands including the tuner capability information; and 
 sending, by the accessory, one or more third commands to the portable media device, the one or more third commands including tuner control information for controlling the tuner. 
 
     
     
       2. The method of  claim 1  wherein the tuner control information includes one or more of: a command for controlling a band setting of the tuner, a command for controlling a frequency setting of the tuner; a command for controlling a mode setting of the tuner, or a command for controlling a power setting of the tuner. 
     
     
       3. The method of  claim 1  wherein the tuner control information is based on the tuner capability information. 
     
     
       4. The method of  claim 1  further comprising receiving, by the accessory, audio data from the portable media device in response to sending the one or more third commands. 
     
     
       5. The method of  claim 1  further comprising receiving, by the accessory, broadcast metadata from the portable media device in response to sending the one or more third commands. 
     
     
       6. The method of  claim 1  further comprising sending, by the accessory, one or more fourth commands to the portable media device, the one or more fourth commands instructing the portable media device to automatically send notifications to the accessory indicating state changes to the tuner. 
     
     
       7. The method of  claim 1  wherein the accessory is configured to communicate with the portable media device wirelessly. 
     
     
       8. The method of  claim 1  further comprising sending, by the accessory, one or more fourth commands to the portable media device requesting status changes of the tuner, the one or more fourth commands including a bitmask identifying a specific status change in the tuner that should invoke the portable media device to send a notification to the accessory. 
     
     
       9. A method comprising:
 sending, by an accessory, one or more first commands to a portable media device, wherein the portable media device includes a tuner configured to tune radio frequency signals, and wherein the one or more first commands request tuner capability information indicating one or more capabilities of the tuner, the tuner capability information including at least one of types of bands the tuner supports, resolution the tuner supports for each band, types of controls the tuner supports, or types of modes the tuner supports; 
 receiving, by the accessory, one or more second commands from the portable media device, the one or more second commands including the tuner capability information; 
 sending, by an accessory, one or more third commands to the portable media device, the one or more third commands requesting tuner state information indicating a current state of the tuner; 
 receiving, by the accessory, one or more fourth commands from the portable media device, the one or more fourth commands including the tuner state information; and 
 sending, by the accessory, one or more fifth commands to the portable media device, the one or more fifth commands including tuner control information for controlling the tuner, wherein the tuner control information is based on the tuner capability information or the tuner state information. 
 
     
     
       10. An accessory comprising:
 an interface adapted to be communicatively coupled with a portable media device having a radio frequency (RF) tuner; and 
 a control component communicatively coupled with the interface and configured to:
 send one or more first commands to the portable media device, the one or more first commands requesting tuner capability information indicating one or more capabilities of the tuner, the tuner capability information including at least one of types of bands the tuner supports, resolution the tuner supports for each band, types of controls the tuner supports, or types of modes the tuner supports; 
 receive one or more second commands from the portable media device, the one or more second commands including the tuner capability information; and 
 send one or more third commands to the portable media device, the one or more third commands including tuner control information for controlling the tuner. 
 
 
     
     
       11. The accessory of  claim 10  wherein the interface includes a connector comprising a plurality of signal pins, the signal pins being arranged to mate with corresponding signal pins on a mating connector of the portable media device. 
     
     
       12. The accessory of  claim 10  wherein the interface is a wireless interface. 
     
     
       13. The accessory of  claim 10  wherein the control component is further configured to:
 send one or more fourth commands to the portable media device, the one or more fourth commands requesting tuner state information indicating a current state of the tuner; and 
 receive one or more fifth commands from the portable media device, the one or more fifth commands including the tuner state information. 
 
     
     
       14. The accessory of  claim 13  wherein the accessory further comprises an output device, and wherein at least a portion of the tuner state information is outputted to a user via the output device. 
     
     
       15. The accessory of  claim 13  wherein the tuner state information includes one or more of: current band information, current frequency information, current mode information, or current received signal strength (RSSI) information. 
     
     
       16. A method comprising:
 receiving, by a portable media device having a radio frequency (RF) tuner, one or more first commands from an accessory, the one or more first commands requesting tuner capability information indicating one or more capabilities of the tuner, the tuner capability information including at least one of types of bands the tuner supports, resolution the tuner supports for each band, types of controls the tuner supports, or types of modes the tuner supports; 
 sending, by the portable media device, one or more second commands to the accessory, the one or more second commands including the tuner capability information; 
 receiving, by the portable media device, one or more third commands from the accessory, the one or more third commands including tuner control information for controlling the tuner; and 
 controlling, by the portable media device, the tuner based on the tuner control information. 
 
     
     
       17. The method of  claim 16  wherein, prior to receiving the one or more first commands, verifying by the portable media device that the accessory has been authenticated to interoperate with the portable media device. 
     
     
       18. The method of  claim 16  wherein the tuner control information specifies a frequency, and wherein the method further comprises, by the portable media device:
 tuning the tuner to the specified frequency; 
 receiving radio signals at the specified frequency; 
 converting the radio signals into audio data; and 
 sending the audio data to the accessory. 
 
     
     
       19. A portable media device comprising:
 a tuner configured to tune radio frequency (RF) signals; 
 a storage device configured to store a plurality of media assets; 
 an interface adapted to be communicatively coupled with an accessory; and 
 a control component configured to:
 receive one or more first commands from the accessory, the one or more first commands requesting tuner capability information indicating one or more capabilities of the tuner, the tuner capability information including at least one of types of bands the tuner supports, resolution the tuner supports for each band, types of controls the tuner supports, or types of modes the tuner supports; 
 send one or more second commands to the accessory, the one or more second commands including the tuner capability information; and 
 receive one or more third commands from the accessory, the one or more third commands including tuner control information for controlling the tuner. 
 
 
     
     
       20. The portable media device of  claim 19  wherein the tuner is configured to tune analog broadcasts or digital broadcasts. 
     
     
       21. The portable media device of  claim 19  wherein the tuner is configured to tune terrestrial signals or satellite signals. 
     
     
       22. The portable media device of  claim 19  wherein the interface includes a connector comprising a plurality of signal pins, the signal pins being arranged to mate with corresponding signal pins on a mating connector of the accessory. 
     
     
       23. The portable media device of  claim 19  wherein the interface is a wireless interface. 
     
     
       24. The portable media device of  claim 19  wherein the portable media device further comprises a media playback component configured to play back media assets stored on the storage device, and wherein the tuner control information includes one or more of: a command for disabling the tuner and enabling media playback via the media playback component, or a command for enabling the tuner and disabling media playback via the media playback component. 
     
     
       25. The portable media device of  claim 19  wherein the portable media device further comprises a headphone jack for accepting a plug for headphones, and wherein the headphones are configured to function as an antenna for the tuner.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application is related to the following commonly-owned U.S. patent applications, which are incorporated herein by reference in their entireties for all purposes: 
     (1) U.S. patent application Ser. No. 11/519,386, titled “METHOD AND SYSTEM FOR CONTROLLING AN ACCESSORY HAVING A TUNER,” filed Sep. 11, 2006, now U.S. Pat. No. 7,441,058, issued Oct. 21, 2008; 
     (2) U.S. patent application Ser. No. 12/208,987, titled “METHOD AND SYSTEM FOR CONTROLLING AN ACCESSORY HAVING A TUNER,” filed Sep. 11, 2008; and 
     (3) U.S. patent application Ser. No. 12/372,689, titled “DIGITAL RADIO TAGGING USING AN RF TUNER ACCESSORY,” filed Feb. 17, 2009. 
     BACKGROUND 
     The present disclosure relates in general to portable media devices that can interoperate with accessories, and in particular to interoperation of a portable media device with an accessory to facilitate control of a radio frequency (RF) tuner included in the portable media device. 
     Generally speaking, an RF tuner is a device that is capable of selecting, or “tuning in,” radio signals at a specified frequency for conversion to another medium (e.g., audio, video, data, etc.). RF tuners are available for tuning in radio signals corresponding to various different types of broadcasts, such as radio and television (TV) broadcasts. The broadcasts can be encoded in analog or digital format. Examples of analog broadcasts include Frequency Modulation (FM) radio, Amplitude Modulation (AM) radio, and National Television Systems Committee (NTSC) TV broadcasts. Examples of digital broadcasts include HD Radio, satellite radio, Advanced Television Systems Committee (ATSC) TV, and Digital Video Broadcasting (DVB) TV broadcasts. 
     In recent years, there has been growing demand for the inclusion of RF tuning functionality in portable media devices. As used herein, a portable media device, or PMD, is a handheld device that is capable of storing and playing back digital media assets such as audio, video, and/or still image files. Some portable media devices, such as the iPod® and iPhone™ (both developed by Apple Inc., assignee of the present application), can provide users a variety of services in addition to media storage and playback. Examples of such services include the storage of personal data such as calendar, contacts, and notes; Internet access; mobile telephony; and the ability to selectively download and run various application programs. 
     Certain existing portable media devices have built-in FM tuners for tuning in analog FM radio stations. However, these built-in tuners are typically operated via an input interface located directly on the portable media device. Generally speaking, these built-in tuners cannot be controlled via separate accessory devices (also referred to herein as “accessories”) that are capable of communicating user input to the portable media device. In addition, these existing built-in tuners are not designed to tune in digital radio (e.g., HD Radio, satellite radio) or digital TV (e.g., ATSC, DVB) broadcasts. 
     SUMMARY 
     Embodiments of the present invention facilitate interoperation between a portable media device having an RF tuner and an accessory device (or “accessory”). In certain embodiments, the portable media device and the accessory can exchange various commands pertaining to the capabilities, state, and/or operation of the tuner. For example, in one set of embodiments the accessory can send one or more commands requesting information about the capabilities of the tuner, and the portable media device can provide the requested capability information. In another set of embodiments, the accessory can send one or more commands requesting execution of a particular action with respect to the tuner (e.g., modification of a tuner setting), and the portable media device can perform the requested action. In this manner, certain embodiments of the present invention enable a user to control the tuner functionality of the portable media device via the accessory, rather than, e.g., via an input interface located directly on the portable media device. 
     In one set of embodiments, an accessory can send one or more first commands to a portable media device, where the one or more first commands request tuner capability information indicating one or more capabilities of a tuner included in the portable media device. The accessory can then receive one or more second commands from the portable media device, where the one or more second commands include the tuner capability information. The accessory can further send one or more third commands to the portable media device, where the one or more third commands include tuner control information for controlling the tuner. 
     In one set of embodiments, the tuner included in the portable media device can be configured to tune in analog and/or digital radio broadcasts. In another set of embodiments, the tuner included in the portable media device can be configured to tune in analog and/or digital TV broadcasts. The broadcasts can originate from terrestrial and/or satellite sources. 
     As used herein, “sending a command” or “receiving a command” is to be interpreted broadly to include any signaling regime where a signal specifying an action and/or including information is sent or received. The signal can be received and interpreted by hardware (e.g., combinatorial logic), software executing on a processor, or a combination of hardware and software. 
     Additionally, sending and/or receiving a command is to be interpreted broadly to include engaging in an exchange of commands. Thus, while the term “command” is sometimes used for a low-level atomic transaction, it can also be used to refer to high-level operations that include multiple low-level commands. 
     A further understanding of the nature and advantages of embodiments of the present invention may be realized by reference to the remaining portions of the specification and the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified illustration of a system according to an embodiment of the present invention. 
         FIG. 2  is a simplified block diagram of a system according to an embodiment of the present invention. 
         FIG. 3  is a flow diagram of a process performed by an accessory for interoperating with a portable media device having an RF tuner according to an embodiment of the present invention. 
         FIG. 4  is a flow diagram of a process performed by a portable media device having an RF tuner for interoperating with an accessory according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for the purposes of explanation, numerous details are set forth in order to provide an understanding of various embodiments of the present invention. It will be apparent, however, to one skilled in the art that certain embodiments can be practiced without some of these details. 
     Embodiments of the present invention facilitate interoperation between a portable media device having an RF tuner and an accessory. In certain embodiments, the portable media device and the accessory can exchange various commands pertaining to the capabilities, state, and/or operation of the tuner. For example, in one set of embodiments the accessory can send one or more commands requesting information about the capabilities of the tuner, and the portable media device can provide the requested capability information. In another set of embodiments, the accessory can send one or more commands requesting execution of a particular action with respect to the tuner (e.g., modification of a tuner setting), and the portable media device can perform the requested action. In this manner, certain embodiments of the present invention enable a user to control the tuner functionality of the portable media device via the accessory, rather than, e.g., via an input interface located directly on the portable media device. 
       FIG. 1  is a simplified illustration of a system  100  according to an embodiment of the present invention. System  100  includes a portable media device (PMD)  102  communicatively coupled with an accessory  104 . As described above, PMD  102  can be any handheld device that is capable of storing and playing back digital media assets such as audio, video, and/or still image files. In a particular embodiment, PMD  102  can be an iPod® or iPhone™ (both developed by Apple Inc., assignee of the present application). PMD  102  can include a user interface comprising user input and/or output devices such as touch-screen display  106 . PMD  102  can also include any number of other user input and/or output devices such as scroll wheels, buttons, keyboards, trackballs, touchpads, microphones, speakers, and the like. 
     PMD  102  can provide a variety of services to a user, such as the management and playback of media assets, mobile telephony and Internet access (e.g., via wireless connections such as Wi-Fi and/or advanced wireless data networks using EDGE or 3G technology), and execution of various application programs that can be installed on PMD  102  by the user. In certain embodiments, PMD  102  can provide an RF tuner application that enables a user to select and listen to/watch various radio and/or TV broadcasts. Some of the services provided by PMD  102  may call for user input that can be provided via an input device located directed on PMD  102  (e.g., touch-screen display  106 ), or via a connected accessory (e.g., accessory  104 ). 
     To enable the reception of radio and/or TV broadcasts, in certain embodiments PMD  102  can incorporate an RF antenna  108  and supporting RF tuner circuitry (not explicitly shown). RF antenna  108  and the RF tuner can be capable of receiving terrestrial and/or satellite signals in any RF band (e.g., AM, FM, and satellite bands). Further, RF antenna  108  and the RF tuner can be capable of receiving analog (e.g., FM radio, AM radio, NTSC, etc.) and/or digital (e.g., HD Radio, satellite radio, ATSC, DVB, etc.) broadcasts. While antenna  108  is shown as being external to PMD  102 , it is to be understood that this is not required, and antenna  108  can be internal to PMD  102 . In some embodiments, antenna  108  can be an attachable device and can also provide dual functions. For example, an antenna input port can be incorporated into a headphone jack, allowing a user to insert a connection to any suitable antenna. In some embodiments, a headphone wire can be leveraged as an antenna to improve reception of radio signals. 
     As shown, PMD  102  can include a PMD connector  110  that can receive an end connector  112  of a cable  114 . PMD connector  110  can include a number of pins assigned to carry various data and control signals between PMD  102  and accessory  104 . In one set of embodiments, PMD connector  110  can include pins for carrying audio signals in digital and/or analog format from PMD  102  to accessory  104  (or vice versa) and control signals as described below for facilitating control of the RF tuner included in PMD  102 . 
     In further embodiments, PMD connector  110  can include pins for providing electrical power and ground connections between PMD  102  and accessory  104 . In a particular embodiment, a certain pin (or pins) can be assigned to deliver power from PMD  102  to accessory  104  while another pin (or pins) can be assigned to deliver power from accessory  104  to PMD  102 . Thus, either device ( 102  or  104 ) can provide power to the other. 
     Accessory  104  can receive the other end connector  116  of cable  114  at an accessory connector  118 . In some embodiments, accessory connector  118  can have a different form factor and/or different number of contacts from PMD connector  110 . In other embodiments, the two connectors can be the same. In still other embodiments, accessory connector  118  can be designed to mate directly with PMD connector  110  such that cable  114  is not required. In further embodiments, some or all communication between PMD  102  and accessory  104  may take place wirelessly (e.g., via Bluetooth or other short-range wireless protocols). 
     Accessory  104  can be a speaker system (as shown), a dock, a combination speaker/dock, or any other type of electronic device that is capable of exchanging signals with PMD  102 . In an embodiment where accessory  104  is a speaker system (or includes some type of audio output device), radio broadcasts received by PMD  102  can be played for a user via accessory  104 . In an embodiment where accessory  104  includes a display device, TV broadcasts received by PMD  102  can be played for a user via accessory  104 . 
     Although not shown, accessory  104  can include additional components that provide services or service enhancements to PMD  102 . Merely by way of example, accessory  104  can include audio/video (“A/V”) out ports that enable A/V signals to be routed from PMD  102  (e.g., via cable  114 ) to an external display/playback device. Accessory  104  can also include user input and/or output devices, such as scroll wheels, buttons, keyboards, trackballs, touchpads, microphones, speakers, touch-screen displays, and the like for providing user input to, and/or presenting information from, PMD  102 . 
     In one set of embodiments, accessory  104  can communicate wirelessly with a remote control  120  via, e.g., infrared signaling or other short-range wireless signals. Remote control  120  can include a number of control buttons  122  that allow a user to communicate instructions to accessory  104 . Accessory  104  can relay these instructions to PMD  102 , thereby allowing a user to control radio/TV playing and/or other functions of PMD  102 . Merely by way of example, remote control  120  can provide buttons for volume control, buttons for changing the current station/channel, buttons for enabling/disabling radio/TV playback, and buttons that can be associated with preset radio stations and/or TV channels the user likes. In some embodiments, accessory  104  can receive user input directly via an input interface located directed on the accessory (not explicitly shown), in addition to or instead of receiving input from remote control  120 . 
     It should be appreciated that system  100  is illustrative and that variations and modifications are possible. For example, PMD  102  can be made in a variety of form factors and configurations and may be able to receive radio and/or TV broadcasts in a variety of formats (including analog, digital, and hybrid digital) from a variety of sources (including terrestrial and satellite transmitters). In addition, in some embodiments PMD  102  may be able to stream broadcast content from a data network such as the Internet. Further, accessory  104  is just one example of a range of accessories to which PMD  102  can be connected; as described above, the term “accessory” can includes any electronic device capable of communicating control signals and information with a PMD. Examples of such communication are described below. 
       FIG. 2  is a simplified block diagram of a system  200  according to an embodiment of the present invention. System  200  includes a PMD  202  (e.g., implementing PMD  102  of  FIG. 1 ) and an accessory  204  (e.g., implementing accessory  104  of  FIG. 1 ). 
     PMD  202  can include a processor  206 , a storage device  208 , an RF tuner  210 , user input/output devices  212 , and an accessory I/O (input/output) interface  214 . Although not shown, PMD  202  can also include other components to provide various enhanced capabilities. For example, in some embodiments PMD  202  can include transceiver components for accessing wireless voice and/or data networks (e.g., using cellular telephone technology, advanced data network technology such as 3G or EDGE, WiFi (IEEE 802.11 family standards), or other mobile communication technologies, or any combination thereof), a GPS receiver, and/or other components. 
     Processor  206  can be implemented as one or more integrated circuits, such as a microprocessor or microcontroller. In some embodiments, processor  206  can be a microprocessor that uses the ARM architecture (a RISC architecture designed by ARM Limited). Processor  206  can be responsible for carrying out one or more functions of PMD  202 . For example, processor  206  can select and play media assets or execute various application programs stored in storage device  208 . Processor  206  can also manage communication with accessory devices (e.g., accessory  204 ) via accessory I/O interface  214 . As described in further detail below, in one set of embodiments processor  206  can execute a radio application such as radio application  216  that allows for radio playback. 
     Storage device  208  can be implemented, for example, using magnetic disk, flash memory, and/or any other non-volatile storage medium. In some embodiments, storage device  208  can include non-removable storage components such as a non-removable hard disk drive or flash memory drive. In other embodiments, storage device  208  can include removable storage media such as flash memory cards. Storage device  208  can provide storage for any programs and/or data used by PMD  202 . For example, storage device  208  can store media assets such as audio, video, still images, or the like, and associated metadata (e.g., asset name, artist, title, genre, playlists, etc.). Storage device  208  can also store information other than media assets, such as information about a user&#39;s contacts (names, addresses, phone numbers, etc.); scheduled appointments and events; notes; and/or other personal information. In still other embodiments, storage device  208  can store one or more programs to be executed by processor  206 , such as video game programs, personal information management programs, programs for playing media assets and/or navigating a media asset database, and so on. 
     In one set of embodiments, storage device  208  can store an RF tuner application program  216  that allows a user to listen to radio programming or watch TV programming via the RF tuner functionality of PMD  202 . For example, RF tuner application  216  can define a user interface that allows a user to select a radio station and/or TV channel, to control volume and other characteristics of the sound and/or video, and to capture identifying information about currently playing content. In some embodiments, when RF tuner application  216  is active, a PMD-specific protocol can be used to pass commands and data between PMD  202  and accessory  204  for controlling RF tuner  210 . A representative set of such commands is described in further detail below. 
     In certain embodiments, storage device  208  can further store radio-related and/or TV-related metadata, such as information relating to favorite station frequencies and/or channels, or metadata accompanying analog and/or digital programming (e.g., Radio Data System (RDS)/Radio Broadcast Data System (RBDS) metadata, Station Information Service (SIS) metadata, Program Service Data (PSD) metadata, digital TV (e.g., ATSC, DVB) metadata, etc.). 
     RF tuner  210  can be used to receive broadcasts via one or more media; any broadcast medium or combination of media can be supported. For example, RF tuner  210 , in conjunction with a suitable antenna (not explicitly shown), can be capable of detecting broadcasts via a wireless medium (e.g., FM or AM radio in analog and/or digital/HD formats, over-the-air TV, satellite TV or radio, WiFi, cellular communication network, etc.). RF tuner  210  may include any hardware and/or software elements usable to extract broadcast data from wired and/or wireless media as desired; the particular components will depend on the medium (or media) supported. Any combination or sub-combination of wired and/or wireless media can be supported. 
     RF tuner  210  can include a content extraction engine  218 , which can incorporate appropriate decoding and processing components to extract audio and/or video signals from a received broadcast; these components can generate analog and/or digital signals suitable for driving video and/or audio output devices, such as display devices and/or speakers. In certain embodiments, such output devices can be components of user input/output devices  212 . In addition or instead, PMD  202  can deliver these signals to accessory  204  via, e.g., accessory I/O interface  214 . 
     In embodiments where RF tuner  210  is configured to tune in to a digital radio broadcast, content extraction engine  218  can extract digital audio data and/or digital metadata from the received signal. Examples of digital metadata formats that can be embedded in digital broadcasts include SIS and PSD, which are based on IBOC Digital Radio Broadcasting Standard NRSC-5 or NRSC-5A. In certain embodiments, the digital audio data can be converted to analog format prior to being sent to an output device (e.g., speakers) or an output interface (e.g., accessory I/O interface  214 , dedicated audio-out port, etc.) of PMD  202 . 
     In embodiments where RF tuner  210  is configured to tune in to a digital TV broadcast, content extraction engine  218  can extract digital audio/video data and/or digital metadata from the received signal. An example a digital metadata format that can be embedded in a digital TV broadcast is defined in ATSC Standard: Program and System Information Protocol for Terrestrial Broadcast and Cable (Revision C) With Amendment No. 1. In certain embodiments, the digital audio/video data can be decoded and converted to analog format prior to being send to an output device (e.g., speakers, display) or an output interface (e.g., accessory I/O interface  214 ) of PMD  202 . 
     In embodiments where RF tuner  210  is configured to tune in to an analog radio broadcast, content extraction engine  218  can extract analog audio data and/or digital metadata from the received signal. Examples of digital metadata formats that can be embedded in conventional analog broadcasts include RDS and RBDS. 
     User input/output devices  212  can be any of a number of devices that allow a user to interact with PMD  202 . As discussed with respect to PMD  102  of  FIG. 1 , such user input/output devices can include scroll wheels, buttons, keyboards, trackballs, touchpads, microphones, speakers, touch-screen displays, and so on. In various embodiments, the user can operate a particular user input device  212  to invoke the functionality of PMD  202 . In addition, a user can view and/or hear output from PMD  202  (e.g., broadcasts received via RF tuner  210 ) via a particular user output device  212 . 
     Accessory I/O interface  214  can include a number of signal paths configured to carry various signals between PMD  202  and accessory  204 . In one set of embodiments, accessory I/O interface  214  includes a 30-pin connector corresponding to the connector used on the iPod® and iPhone™. The 30-pin connector can provide connections for power and ground as well as for various wired communication interfaces such as USB, FireWire, and/or universal asynchronous receiver/transmitter (UART). In addition or instead, accessory I/O interface  214  can include a wireless interface such as Bluetooth (i.e., an interface compliant with a Bluetooth® specification (e.g., Bluetooth specification v2.1+ EDR; other versions can also be used) promulgated by the trade association Bluetooth SIG, Inc. (headquartered in Bellevue, Wash.)). Other wireless protocols can also be supported. Thus, accessory I/O interface  214  can support multiple communication channels including wired and/or wireless channels, and a given accessory can use any or all of these channels. 
     Accessory  204  can include a controller  220 , user input/output devices  222 , and a PMD I/O interface  224 . Accessory  204  is representative of a broad range of electronic devices to which PMD  202  can be connected, and it is understood that such devices can vary widely in capability, complexity and form factor. Various accessories may include components not shown in  FIG. 2 , including but not limited to storage devices (disk, memory, etc.), ports for connecting to external speakers and/or display devices, and so on. 
     Controller  220  can be implemented as one or more integrated circuits, such as a microprocessor or microcontroller. In various embodiments, controller  220  can execute program code to perform various functions associated with accessory  204 . For example, in some embodiments where accessory  220  incorporates a sound system (e.g., speaker system  104  shown in  FIG. 1 ), program code executed by controller  220  can include programs for digital audio decoding, analog or digital audio processing, and the like. Controller  220  can also manage communication with PMDs (e.g., PMD  202 ) via PMD I/O interface  224 . 
     User input/output devices  222  can be any of a number of devices that allow a user to interact with accessory  204 . For example, such user input/output devices can include scroll wheels, buttons, keyboards, trackballs, touchpads, microphones, speakers, touch-screen displays, and so on. A user can operate input/output devices  222  to invoke the functionality of accessory  204  and to view and/or hear output from accessory  204 . For example, in one set of embodiments a user can operate an input device  222  to remotely control RF tuner  210  included in PMD  202 . In some embodiments, user input/output devices  222  can include a wireless (e.g., infrared) receiver that receives control signals from a remote control (e.g., remote control  120  of  FIG. 1 ). 
     PMD I/O interface  224  can include a number of signal paths configured to carry various signals between accessory  204  and PMD  202 . In one set of embodiments, PMD I/O interface  224  includes a 30-pin connector corresponding to the connector used on the iPod® and iPhone™. Alternatively or additionally, PMD I/O interface  224  can include a different connector or a wireless interface (e.g., Bluetooth or the like). 
     It should be appreciated that system  200  is illustrative and not intended to limit embodiments of the present invention. For example, PMD  202  and accessory  204  may each have other capabilities or include other components that are not specifically described. One of ordinary skill in the art will recognize many variations, modifications, and alternatives. 
     Accessory I/O interface  214  of PMD  202  and PMD I/O interface  224  of accessory  204  allow PMD  202  to be connected to accessory  204  and subsequently disconnected from accessory  204 . As used herein, PMD  202  and accessory  204  are “connected” whenever a communication channel is open between PMD I/O interface  224  and accessory I/O interface  214 . Such connection can be achieved via direct physical connection, e.g., with mating connectors; indirect physical connection, e.g., via a cable; and/or wireless connection, e.g., via Bluetooth. 
     In one set of embodiments, PMD  202  and accessory  204  can communicate by exchanging commands and data according to a PMD-specific protocol. The commands and data can be communicated, e.g., using any wired or wireless transport medium provided by accessory I/O interface  214  and PMD I/O interface  224  of  FIG. 2 . According to one aspect, the PMD-specific protocol can define a format for messages transmitted between PMD  202  and accessory  204 . For instance, the protocol can specify that each message (also referred to herein as a command) is sent in a packet with a header and an optional payload. The header can provide basic information such as a start indicator, length of the packet, and a command to be processed by the recipient. The payload can provide data associated with the command. In some embodiments, the amount of associated data can be different for different commands, and some commands may provide for variable-length payloads. In some embodiments, the commands can be defined such that any particular command code is valid in only one direction. The packet can also include error-detection or error-correction codes as known in the art. 
     According to another aspect, the PMD-specific protocol can define a number of “lingoes,” where a “lingo” refers generally to a group of related commands that can be supported (or unsupported) by various classes of accessories. In one set of embodiments, a command can be uniquely identified by a first byte identifying the lingo to which the command belongs and a second byte identifying the particular command within the lingo. Other command structures may also be used. It is not required that all accessories, or all PMDs to which an accessory can be connected, support every lingo defined within the protocol or every command of a particular lingo (for instance, different devices might use different versions of a given lingo). 
     In one set of embodiments, the PMD-specific protocol can include a general lingo that enables certain core communication functions between PMD  202  and accessory  204 . For example, the general lingo can include commands enabling PMD  202  and accessory  204  to identify themselves to each other and to provide information about their respective capabilities, including which (if any) other lingoes each supports and which capabilities of the other device each intends to use while connected. The general lingo can also include authentication commands that PMD  202  can use to verify the purported identity and capabilities of accessory  204  (or vice versa). In some cases, accessory  204  (or PMD  202 ) can be blocked from invoking certain commands or lingoes if the authentication is unsuccessful. 
     In some embodiments, the general lingo can also provide a notification capability. For example, PMD  202  can generate notifications in response to various events that change the status of PMD  202 , such as launching or exiting various applications (e.g., radio application  216 ), changing state within an application (e.g., when a new track begins playing during a radio broadcast), and so on. Accessory  204 , when connected to PMD  202 , can “register” to receive all notifications or selected classes of notifications by sending a registration command to PMD  202 . Once accessory  204  has registered for a particular class (or classes) of notifications, PMD  202  automatically begins to send notifications to accessory  204  whenever any event within the registered class(es) occurs. Notification conveniently allows accessory  204  to maintain current information about the status of PMD  202  without having to send requests for status information. 
     The PMD-specific protocol can also include various other lingoes, such as a simple remote lingo that allows accessory  204  to send a command indicating a function of PMD  202  to be invoked, a remote user interface lingo that can be used to communicate commands and data related to replicating all or part of a user interface of PMD  202  on accessory  204  (thereby supporting a more advanced remote control), a storage lingo that allows accessory  204  to store data on PMD  202  (or vice versa), and so on. In one set of embodiments, the PMD-specific protocol can include an RF tuner lingo that allows a user to control an RF tuner (e.g., RF tuner  210 ) in PMD  202  by operating accessory  204  (described in greater detail with respect to  FIGS. 3 and 4  below). In this manner, a user can control the tuner functionality of PMD  202  via accessory  204 , rather than, e.g., via an input interface located directly on PMD  202 . 
       FIG. 3  is a flow diagram illustrating a process  300  performed by an accessory (e.g., accessory  204 ) for interoperating with a portable media device having an RF tuner (e.g., PMD  202 ) according to an embodiment of the present invention. Process  300  can be implemented by accessory  204  in hardware, software, or a combination thereof. As software, process  300  can be encoded as program code stored on a machine-readable storage medium. 
     Process  300  begins when accessory  204  establishes communication with PMD  202  (block  302 ). In one set of embodiments, this can include identifying and authenticating PMD  202  using the general lingo of the PMD-specific protocol described above. 
     At block  304 , accessory  204  can send a command to PMD  202  indicating that a user wishes to start listening to the radio or watching TV. Examples of such commands include EnterRadioMode and EnterTVMode. In certain embodiments, PMD  202  can respond to the EnterRadioMode or EnterTVMode command by launching RF tuner application  216  and exiting any other currently-running audio/video playback applications (e.g., a media playback application for playing back stored media assets). 
     At block  306 , accessory  204  can send one or more commands to PMD  202  requesting information about the capabilities of RF tuner  210 . An example of such a command is GetTunerCaps. In one set of embodiments, the GetTunerCaps command can specify particular tuner features that accessory  204  is interested in, such as the types of bands the tuner supports (e.g., FM band, AM band, etc.), the resolution the tuner supports for each band, the types of controls the tuner supports (e.g., seek, next station, previous station, next channel, previous channel, etc.), and/or the types of modes the tuner supports (e.g., force monophonic mode, stereo blend mode, etc.). In other embodiments, the GetTunerCaps command can simply request information about all of the available capabilities of RF tuner  210 . 
     In response to sending the GetTunerCaps command, accessory  204  can receive one or more commands from PMD  202  including the requested tuner capability information (block  308 ). An example of such a command is RetTunerCaps. In an embodiment where RF tuner  210  is a radio tuner, the RetTunerCaps command can include a data field including values for, e.g., FM band U.S., HD radio capable, tuner power control capable, status change notification capable, FM resolution, tuner seek capable, tuner seek RSSI threshold capable, force monophonic mode capable, stereo blend capable, FM tuner deemphasis select capable, AM resolution, RDS/RBDS data capable, tuner channel RSSI indication capable, stereo source indicator capable, and so on. 
     In certain embodiments, accessory  204  can store the received tuner capability information locally for future reference. In further embodiments, accessory  204  can output, based on the tuner capability information, one or more indications to a user (via, e.g., output device  222 ) about the presence and/or absence of certain tuner features. 
     At block  310 , accessory  204  can send one or more commands to PMD  202  requesting notification of status changes or desired types of data pertaining to the tuner. Examples of such commands include SetStatusNotifyMask, SetRdsNotifyMask, and SetHDDataNotifyMask. The SetStatusNotifyMask command can include a bitmask identifying specific status changes in RF tuner  210  that should invoke a notification command from PMD  202  to accessory  204 . For instance, the bitmask can specify that a notification should be generated whenever a new audio track or new TV program begins playing during a broadcast. 
     The SetRdsNotifyMask and SetHDDataNotifyMask commands can include bitmasks identifying specific types of broadcast metadata received via RF tuner  210  that should invoke a notification command from PMD  202  to accessory  204 . In certain embodiments, the SetRdsNotifyMask command can apply to RDS/RBDS metadata received in analog radio broadcasts, and the SetHDDataNotifyMask command can apply to SIS and/or PSD metadata received in digital/HD radio broadcasts. 
     Once accessory  204  has registered for notifications via the commands sent at block  310 , accessory  204  can receive one or more commands asynchronously from PMD  202  reporting the requested notifications (block  312 ). For example, in response to the SetStatusNotifyMask command, accessory  202  can receive a StatusChangeNotify command from PMD  202  upon the occurrence of a specified status change. As another example, in response to the SetRdsNotifyMask or SetHDDataNotifyMask commands, accessory  204  can receive an RdsReadyNotify or HDDataReadyNotify command from PMD  202  when the specified types of RDS/RBDS or SIS/PSD metadata are received via RF tuner  210  respectively. 
     In some embodiments, upon receiving the RdsReadyNotify or HDDataReadyNotify command, accessory  204  can request that PMD  202  send the metadata via a GetRdsData or GetHDData command. In response, accessory  204  can receive a RetRdsData or RetHDData command from PMD  202  including the requested metadata. 
     At block  314 , accessory  204  can send one or more commands to PMD  202  requesting information about the state and/or status of RF tuner  210 . Examples of such commands include GetTunerBand, GetTunerFreq, GetTunerStatus, GetHDProgramService, GetHDProgramServiceCount, GetStatusNotifyMask, GetRdsNotifyMask, GetHDDataNotifyMask, GetRdsReadyStatus, and GetHDDataReadyStatus. The GetTunerBand command can request the tuner&#39;s current RF band setting (e.g., AM or FM). The GetTunerFreq command can request the tuner&#39;s current frequency setting (e.g., 87.5 MHz). In certain embodiments, the tuner frequency can be expressed in kilohertz, e.g., 87500 for 87.5 MHz. The GetTunerStatus command can request the tuner&#39;s current status, such as power level, received signal strength, operating modes, etc. 
     In embodiments where RF tuner  210  supports the tuning of digital/HD Radio broadcasts, the GetHDProgramService command can request the currently tuned HD Radio program. Further, the GetHDProgramServiceCount command can request a count of HD Radio Programs broadcast at the current tuner frequency. 
     In embodiments where RF tuner  210  supports the tuning of digital TV (e.g., ATSC, DVB) broadcasts, the GetHDProgramService command can request the currently tuned sub-channel (or minor channel) for a major channel. Further, the GetHDProgramServiceCount command can request a count of sub-channels for the major channel. 
     The GetStatusNotifyMask, GetRdsNotifyMask, and GetHDDataNotifyMask commands can request the current bitmasks set in PMD  202  via previous invocations of the SetStatusNotifyMask, SetRdsNotifyMask, and SetHDDataNotifyMask commands. The GetRdsReadyStatus and GetHDDataReadyStatus commands can be used by accessory  204  to manually check whether specific types of RDS/RBDS metadata or SIS/PSD metadata have been received at PMD  202  via RF tuner  210  (rather than waiting for notifications from PMD  202 ). 
     In response to sending the commands described above at block  314 , accessory  204  can receive one or more commands from PMD  202  including the requested tuner state information (block  316 ). Examples of such commands include RetTunerBand, RetTunerFreq, RetTunerStatus, RetHDProgramService, RetHDProgramServiceCount, RetStatusNotifyMask, RetRdsNotifyMask, RetHDDataNotifyMask, RetRdsReadyStatus, and RetHDDataReadyStatus. In various embodiments, these commands can include the information requested by their complementary “Get” commands respectively. Like the capability information described above, in certain embodiments accessory  204  can output information about the tuner&#39;s state to a user via, e.g., output device  222 . 
     At block  318 , accessory  204  can send one or more commands to PMD  202  including information for controlling, or changing one or more settings of, RF tuner  210 . Examples of such commands include SetTunerCtrl, SetTunerMode, SetTunerBand, SetTunerFreq, SetTunerSeekRssi, TunerSeekStart, and SetHDProgramService. The SetTunerCtrl command can include data for modifying various control parameters used by RF tuner  210 , such as a power parameter for turning the tuner on or off and a notification parameter for turning the notification feature on or off. The SetTunerMode command can include data for enabling or disabling certain modes of operation of RF tuner  210 . For example, the SetTunerMode command can include a data field specifying FM tuner resolution 200 kHz, stereo allowed, no stereo blend, FM tuner deemphasis 75 μs, and AM tuner resolution 10 kHz. 
     The SetTunerBand command can include data specifying a tuner band to set, such as FM U.S. band. The SetTunerFreq command can include data specifying a frequency to be tuned, such as 87.5 Mhz. 
     The SetTunerSeekRssi command can include data specifying a desired RSSI threshold value. In certain embodiments, the RSSI threshold value indicates a threshold amount of power that must be present at a specific frequency in order for RF tuner  210  to tune in to that frequency during a seek operation. The TunerSeekStart command can instruct RF tuner  210  to begin a seek operation. In some embodiments, the TunerSeekStart command can include data specifying one of several types of seeks to perform. The types of seeks can include:
         Seeking up from beginning of band using or not using the RSSI threshold value;   Seeking down from end of band using or not using the RSSI threshold value;   Seeking up from the current frequency using or not using the RSSI threshold value;   Seeking down from the current frequency using or not using the RSSI threshold value;   Seeking up from beginning of band for an HD Radio signal using or not using the RSSI threshold value;   Seeking down from end of band for an HD Radio signal using or not using the RSSI threshold value;   Seeking up from the current frequency for an HD Radio signal using or not using the RSSI threshold value; and   Seeking down from the current frequency for an HD Radio signal using or not using the RSSI threshold value.       

     In one set of embodiments, a seek operation using the RSSI threshold value can complete when either of the following two conditions is satisfied:
         A channel was located within the band that satisfies the RSSI threshold value; or   No channel was located within the band that satisfies the RSSI threshold value. The seek has traversed the entire band and wrapped back to the beginning tuner frequency without locating a valid channel. If no channel is found, it may indicate that the threshold is too high for the current radio reception area.       

     In one set of embodiments, a seek operation not using the RSSI threshold value can complete when either of the following two conditions is satisfied:
         A channel was located within the band that satisfies the criteria of the tuner&#39;s seek function. This may result in moving one or more channel spacings and wrapping around at the band ends.   No channel was located within the band that satisfies the criteria of the tuner&#39;s seek function. The seek has traversed the entire band and wrapped back to the beginning tuner frequency without locating a valid channel.       

     In one set of embodiments, an HD Radio seek operation skips non-HD channels and stops only on channels with HD Radio signals present. The seek can complete when either of the following two conditions is satisfied:
         An HD Radio channel was located within the band that satisfies the criteria of the tuner&#39;s seek function. This may result in moving one or more channel spacings and wrapping around at the band ends.   No HD Radio channel was located within the band that satisfies the criteria of the tuner&#39;s seek function. The seek has traversed the entire band and wrapped back to the beginning tuner frequency without locating a valid HD Radio channel.       

     In certain embodiments, accessory  202  can receive a TunerSeekDone command from PMD  202  upon completion of a seek operation. The TunerSeekDone command can include data specifying the tuned frequency and the current station&#39;s RSSI value. 
     In embodiments where RF tuner  210  supports the tuning of digital/HD Radio broadcasts, the SetHDProgramService command can include data specifying a desired HD Radio program at a specific frequency. In response to receiving the SetHDProgramService command, RF tuner  210  can tune to the desired HD Radio program. In one set of embodiments, the command can include a setting that disables all audio decoding and output by PMD  202 . This enables PMD  202  to retrieve information for all available HD Radio programs prior to selecting a particular program&#39;s audio to be decoded and output. 
     In embodiments where RF tuner  210  supports the tuning of digital TV (e.g., ATSC, DVB) broadcasts, the SetHDProgramService command can include data specifying a desired digital TV program at a specific sub-channel. In response to receiving the SetHDProgramService command, RF tuner  210  can tune to the desired digital TV program. 
     Although not shown in  FIG. 3 , in some embodiments the tuner control information that is sent by accessory  204  at block  318  can be based on the tuner capability, tuner state, and/or notification information received at blocks  308 ,  312 , and  316  respectively. For example, the accessory&#39;s sending of a tuner control command can be enabled by the accessory having previously obtained information from PMD  202  that RF tuner  210  (or PMD  202 ) has the requisite capability to support the command. Similarly, the accessory&#39;s sending of a tuner control command can be disabled by the accessory having previously obtained information from PMD  202  that RF tuner  210  (or PMD  202 ) does not have the requisite capability to support the command. In certain embodiments, if accessory  204  sends a tuner control command at block  318  that is not supported by RF tuner  210  or PMD  202 , accessory  204  can receive a command from PMD  202  indicating that the control command cannot be processed. 
     At block  320 , accessory  204  can receive audio and/or video data from PMD  202  generated from a broadcast received via RF tuner  210 . In embodiments where the broadcast is an analog radio broadcast, accessory  204  can receive analog audio signals from PMD  202 . In embodiments where the broadcast is a digital radio broadcast (e.g., HD Radio, satellite radio, etc.), accessory  204  can receive digital and/or analog audio signals from PMD  202 . In embodiments where the broadcast is an analog TV broadcast, accessory  204  can receive analog audio/video signals from PMD  202 . In embodiments where the broadcast is a digital TV broadcast (e.g., ATSC, DVB), accessory  204  can receive digital and/or analog audio/video signals from PMD  202 . Accessory  204  can also receive other types of data, such as metadata included in the broadcast. Examples of such metadata include RDS/RBDS metadata (in the case of an analog radio broadcast) and SIS or PSD metadata (in the case of a digital/HD radio broadcast). In these embodiments, accessory  204  can output the received metadata to a user via an output device of the accessory (e.g., output device  222 ). 
     At block  322 , accessory  204  can send a command to PMD  202  indicating that the PMD should exit radio/TV mode. Examples of such commands include ExitRadioMode and ExitTVMode. In one set of embodiments, the ExitRadioMode or ExitTVMode command can be sent in response to a user entering an input signal via the accessory indicating that the user no long wishes to listen to the radio or watch TV. If the ExitRadioMode or ExitTVMode command is not sent, accessory  204  can continue to receive/send commands and/or data per blocks  306 - 320  until, e.g., PMD  202  and accessory  204  become disconnected, or until PMD  202  decides to exit radio/TV mode. 
       FIG. 4  is a flow diagram of a process  400  performed by a portable media device having an RF tuner (e.g., PMD  202 ) for interoperating with an accessory (e.g., accessory  204 ) according to an embodiment of the present invention. In one set of embodiments, process  400  can be performed by PMD  202  while process  300  is being performed by accessory  204 . Process  400  can be implemented by PMD  202  in hardware, software, or a combination thereof. As software, process  400  can be encoded as program code stored on a machine-readable storage medium. 
     Process  400  begins when PMD  202  establishes communication with accessory  204  (block  402 ). In one set of embodiments, this can include identifying and authenticating accessory  204  using the general lingo of the PMD-specific protocol described above. 
     At block  404 , PMD  202  can enter radio or TV mode. In some embodiments PMD  202  can enter radio/TV mode in response to a command received from accessory  204  (e.g., block  304  of process  300 ). In alternative embodiments, PMD  202  can enter radio/TV mode in response to a user entering an input signal via user input device  212  of PMD  202 , or to establishing communication with accessory  204  at block  402 . In certain embodiments, entering radio/TV mode can cause PMD  202  to launch RF tuner application  216  and exit any other currently-running audio/video playback applications (e.g., a media playback application for playing back stored media assets). If radio/TV mode is not entered immediately, process  400  can wait at block  404  until radio mode is to be entered; PMD  202  can perform other operations while process  400  waits. 
     At block  406 , PMD  202  can receive one or more commands from accessory  204  requesting information about the capabilities of RF tuner  210 . An example of such a command is GetTunerCaps (described above with respect to block  306  of process  300 ). In response, PMD  202  can send one or more commands to accessory  204  including the requested tuner capability information (block  408 ). An example of such a command is RetTunerCaps (described above with respect to block  308  of process  300 ). 
     At block  410 , PMD  202  can receive one or more commands from accessory  204  requesting notification of status changes or desired types of data pertaining to the tuner. Examples of such commands include SetStatusNotifyMask, SetRdsNotifyMask, and SetHDDataNotifyMask (described above with respect to block  310  of process  300 ). In response, PMD  202  can register accessory  204  to receive the requested notifications, and can send one or more commands asynchronously to accessory  204  reporting the requested notifications (block  412 ). Examples of such commands include StatusChangeNotify, RdsNotify and HDDataReadyNotify (described above with respect to block  312  of process  300 ). 
     In some embodiments, upon receiving the RdsReadyNotify or HDDataReadyNotify command, PMD  202  can receive a GetRdsData or GetHDData command from accessory  204  requesting the RDS/RBDS or SIS/PSD metadata. In response, PMD  202  can send a RetRdsData or RetHDData command to accessory  204  including the RDS/RBDS or SIS/PSD metadata. 
     At block  414 , PMD  202  can receive one or more commands from accessory  204  requesting information about the state and/or status of RF tuner  210 . Examples of such commands include GetTunerBand, GetTunerFreq, GetTunerStatus, GetHDProgramService, GetHDProgramServiceCount, GetStatusNotifyMask, GetRdsNotifyMask, GetHDDataNotifyMask, GetRdsReadyStatus, and GetHDDataReadyStatus (described above with respect to block  314  of process  300 ). In response, PMD  202  can send one or more commands to accessory  204  including the requested tuner state information (block  416 ). Examples of such commands include RetTunerBand, RetTunerFreq, RetTunerStatus, RetHDProgramService, RetHDProgramServiceCount, RetStatusNotifyMask, RetRdsNotifyMask, RetHDDataNotifyMask, RetRdsReadyStatus, and RetHDDataReadyStatus (described above with respect to block  316  of process  300 ). 
     At block  418 , PMD  202  can receive one or more commands from accessory  204  including information for controlling, or changing one or more settings of, RF tuner  210 . Examples of such commands include SetTunerCtrl, SetTunerMode, SetTunerBand, SetTunerFreq, SetTunerSeekRssi, TunerSeekStart, and SetHDProgramService (described above with respect to block  318  of process  300 ). 
     At block  420 , PMD  202  can generate audio and/or video data from radio signals received via RF tuner  210  and send the audio/video data to accessory  204 . In certain embodiments, the audio/video data can be generated in response to one or more tuner control commands received at block  418 . For example, if PMD  202  receives a SetTunerFreq command to change the tuner frequency to 87.5 Mhz, PMD  202  can cause RF tuner  210  to tune in to 87.5 Mhz, receive radio signals at that frequency, and convert the radio signals to audio signals for transmission to accessory  204 . In embodiments where the broadcast is an analog radio broadcast, PMD  202  can send analog audio signals to accessory  204 . In embodiments where the broadcast is a digital radio broadcast (e.g., HD Radio, satellite radio, etc.), PMD  202  can send digital and/or analog audio signals to accessory  204 . In embodiments where the broadcast is an analog TV broadcast, PMD  202  can send analog audio/video signals to accessory  204 . In embodiments where the broadcast is a digital TV broadcast (e.g., ATSC, DVB), PMD  202  can send digital and/or analog audio/video signals to accessory  204 . PMD  202  can also send other types of data to accessory  204 , such as metadata included in the broadcast. Examples of such metadata include RDS/RBDS metadata (in the case of an analog radio broadcast) and SIS or PSD metadata (in the case of a digital/HD radio broadcast). 
     At block  422 , PMD  202  can exit radio/TV mode. In some embodiments, PMD  202  can exit radio/TV mode in response to a command received from accessory  204  (e.g., block  322  of process  300 ). In alternative embodiments, PMD  202  can exit radio/TV mode in response to a user entering an input signal via input device  212  of PMD  202 , or to PMD  202  becoming disconnected from accessory  204 . In one set of embodiments, exiting radio/TV mode can cause PMD  202  to exit RF tuner application  216 . In further embodiments, if any other audio/video playback application (e.g., a media playback application for playing stored media assets) was active at the time radio/TV mode was entered at block  404 , that audio playback application may be automatically re-launched upon exiting radio/TV mode at block  422 . If no condition for exiting radio/TV mode is triggered, processing can return to any of blocks  406 - 420 . 
     It should be appreciated that processes  300  and  400  are illustrative and that variations and modifications are possible. Blocks described as sequential may be executed in parallel, order of blocks may be varied, and blocks may be modified, combined, added, or omitted. In one set of embodiments, PMD  202  can return one or more acknowledgement commands to accessory  204  that acknowledge receipt and/or processing of a previous command sent by accessory  204 . In cases where a command sent by accessory  204  includes a request for data (e.g., the commands requesting tuner capability information at block  306  of process  300 ), acknowledgment can be implicit in the return command sent by PMD  202  that includes the requested data. 
     Further, it should be appreciated that the commands described with respect to processes  300  and  400  are illustrative and not intended to limit embodiments of the present invention. For example, some of the commands can be replaced with other commands or a combination of commands. In certain embodiments, some of the commands may not be supported by particular PMDs or accessories. 
     While the invention has been described with respect to specific embodiments, one of ordinary skill in the art will recognize that numerous modifications are possible. For example, a “PMD” as used herein refers generally to any portable device with any form of radio receiving capability; a broad range of functionality may be incorporated, including other media playback capability and/or two-way communication capability. Similarly, the term “accessory” can include any electronic device capable of communication with a PMD to control RF tuner operations. An “RF tuner” as used herein can receive a variety of broadcast media including terrestrial radio (analog, digital, or hybrid digital), satellite radio, Internet radio, analog TV, digital TV, and satellite TV. 
     Embodiments of the present invention can be realized using any combination of dedicated components and/or programmable processors and/or other programmable devices. The various processes described herein can be implemented on the same processor or different processors in any combination. Accordingly, where components are described as being configured to perform certain operations, such configuration can be accomplished, e.g., by designing electronic circuits to perform the operation, by programming programmable electronic circuits (such as microprocessors) to perform the operation, or any combination thereof. Processes can communicate using a variety of techniques including but not limited to conventional techniques for interprocess communication, and different pairs of processes may use different techniques, or the same pair of processes may use different techniques at different times. Further, while the embodiments described above may make reference to specific hardware and software components, those skilled in the art will appreciate that different combinations of hardware and/or software components may also be used and that particular operations described as being implemented in hardware might also be implemented in software or vice versa. 
     Computer programs incorporating various features of the present invention may be encoded on various computer readable storage media; suitable media include magnetic disk or tape, optical storage media such as compact disk (CD) or DVD (digital versatile disk), flash memory, and the like. Computer readable media encoded with the program code may be packaged with a compatible device, or the program code may be provided separately from other devices (e.g., via Internet download). 
     Thus, although the invention has been described with respect to specific embodiments, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20090903
Publication Date: 20120807
Grant Date: 20120807
Priority Date: 20090903
Inventors: BOLTON LAWRENCE
YEW JASON J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B5/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/72", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 43625614