Abstract:
A method for accessory management and data communication between a portable electronic device and an accessory via audio port is disclosed. The method involves using a microphone line of the accessory in different communication modes including a MIC data mode and a power mode. In the MIC data mode, the MIC line disconnects from a microphone load to operate on a voltage above a predetermined threshold whenever the accessory needs to communicate with the host electronic device. In the MIC power mode, the MIC line connects with the microphone load for the normal operation of the microphone.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The application claims priority to U.S. Provisional Patent Application No. 61/953,454, filed May 14, 2014, which application is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    A. Technical Field 
         [0003]    The present invention relates generally to accessory management and data communication via an audio port on an electronic device. 
         [0004]    B. Background of the Invention 
         [0005]    Audio sockets have been commonly used in various electronic devices, such as computers, laptops, media players, smart phones, etc. to communicate with audio accessories having audio jacks. The mostly common used jack plugs have 2.5 mm, 3.5 mm or 6.35 mm (¼ inch) configurations with 2, 3 or 4 conductors for mono, stereo or stereo plus microphone compatibility. Stereo 3.5 mm jacks may be used for line in/out, headset out, loudspeaker out, microphone in, etc. Three-conductor connectors are common on older electronic devices, while 4-conductor 3.5 mm connectors are more commonly used on modern electronic devices, including most smart phones. 
         [0006]    A 2-conductor jack is called TS connector with a tip and a sleeve for mono audio communication. A 3-conductor jack is called TRS connector with a tip, a ring and a sleeve for stereo audio communications. A 4-conductor jack is usually called TRRS connector with a tip, two rings and a sleeve for stereo plus microphone line communications. In certain circumstances, it is desirable to use a TRRS jack to transmit additional audio microphone signal to cellular phones. 
         [0007]    Efforts have been done to explore further potential applications using audio jack connection. Given the variety in the audio accessories of different characteristics and preferred settings, it would be desirable to provide improved accessory management and data communication via audio port for supporting interactions between electronic devices and accessories. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention relates to accessory management and data communication, and more particularly, to systems and methods for accessory management and data communication between a portable electronic device and an accessory via audio port. 
         [0009]    The method involves using a microphone line of the accessory in different communication modes including a MIC data mode and a power mode. In the MIC data mode, the MIC line disconnects from a microphone load to operate on a voltage above a predetermined threshold whenever the accessory needs to communicate with the host electronic device. In the MIC power mode, the MIC line connects with the microphone load for the normal operation of the microphone. 
         [0010]    In certain embodiments, communication starts after the jack insertion is detected. The accessory&#39;s ID and audio jack configuration are initially checked. The audio jack configuration check verifies the type of the audio jack (TS, TRS or TRRS jack). For a TS or TRS jack, the MIC line is powered off. For a traditional TRRS jack without accessory ID, the MIC line is powered with a bias voltage. For a TRRS jack with accessory ID, the MIC line communication is detected by checking the MIC line floating voltage with a predetermined reference voltage. The communication on MIC line may be a 1-wire communication to power up the accessory and to allow communication and authentication at the same time. In some other embodiments, the method of communication with the MIC line superimposes the data line over the power line. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Reference will be made to exemplary embodiments of the present invention that are illustrated in the accompanying figures. Those figures are intended to be illustrative, rather than limiting. Although the present invention is generally described in the context of those embodiments, it is not intended by so doing to limit the scope of the present invention to the particular features of the embodiments depicted and described. 
           [0012]      FIG. 1  is a schematic diagram of an electronic device in communication with an accessory in a system via an audio jack in accordance with an embodiment of the present invention. 
           [0013]      FIG. 2  is an exemplary accessory block diagram of an accessory according to various embodiments of the invention. 
           [0014]      FIG. 3  is an exemplary block diagram of the electronic device in communication with an accessory according to various embodiments of the invention. 
           [0015]      FIG. 4  is a flow diagram according to various embodiments of the invention. 
           [0016]      FIG. 5  is a system state diagram according to various embodiments of the invention. 
           [0017]      FIG. 6  is a block diagram when the accessory is in MIC mode according to various embodiments of the invention. 
           [0018]      FIG. 7  is a block diagram when the accessory is in accessory mode according to various embodiments of the invention. 
           [0019]      FIG. 8  is a system operating region diagram according to various embodiments of the invention. 
       
    
    
       [0020]    One skilled in the art will recognize that various implementations and embodiments of the invention may be practiced in accordance with the specification. All of these implementations and embodiments are intended to be included within the scope of the invention. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. The present invention may, however, be practiced without some or all of these details. The embodiments of the present invention described below may be incorporated into a number of different electrical components, circuits, devices, and systems. Structures and devices shown in block diagram are illustrative of exemplary embodiments of the present invention and are not to be used as a pretext by which to obscure broad teachings of the present invention. Connections between components within the figures are not intended to be limited to direct connections. Rather, connections between components may be modified, re-formatted, or otherwise changed by intermediary components. 
         [0022]    When the specification makes reference to “one embodiment” or to “an embodiment”, it is intended to mean that a particular feature, structure, characteristic, or function described in connection with the embodiment being discussed is included in at least one contemplated embodiment of the present invention. Thus, the appearance of the phrase, “in one embodiment,” in different places in the specification does not constitute a plurality of references to a single embodiment of the present invention. 
         [0023]    Various embodiments of the invention are used for accessory management and data communication via audio port in systems comprised of one or more integrated circuits (IC). An IC may be a memory, microcontroller, microprocessor, secure authenticator or any other devices within a system that communicates and/or receives information within the system. These systems, and the IC(s) therein, may be integrated on a single component or contain discrete components. Furthermore, embodiments of the invention are applicable to a diverse set of techniques and methods. 
         [0024]      FIG. 1  shows a schematic diagram of a system  100  according to various embodiments of the invention. The system  100  comprises an electronic device  200  in communication with an accessory  300 . Communication between the two devices occurs on an audio jack  310  on the accessory  300  and an audio socket  210  on the electronic device  200 . 
         [0025]    The electronic device  200  may be a computer device, a laptop, a portable media player, such as a MP3 player, a cellular phone, etc. The accessory  300  may be an audio accessory such as a microphone, a headphone, loudspeakers, an audio amplifier, or be an electronic accessory having audio jack for voice and data communications. In an embodiment, the accessory  300  has a stereo or mono earphone and a microphone for audio input to the electronic device  200 . 
         [0026]    The audio jack  310  may have 2.5 mm, 3.5 mm or 6.35 mm (¼ inch) configurations with 2, 3 or 4 conductors (TS, TRS, TRRS) for mono, stereo or stereo plus microphone compatibility. The audio socket  210  may or may not have the matching configuration with the audio jack  310 . For example, the audio socket is a TRRS socket, while the audio jack is a TRS jacket. 
         [0027]    In one embodiment, the electronic device  200  has an audio socket  210 , an  12 C interface  220 , a microprocessor  230 , a memory  240 , and a power source  250 . The microprocessor  230  is configured to operatively connect to the  12 C interface  220 , the memory  240  and power source  250 . The  12 C interface  220  is an Inter-Integrated Circuit used for attaching peripheral audio socket  210  to the microprocessor  230 . The memory  240  is configured to store a non-volatile computer readable logic or code for the implementation of desired function when the logic or code is executed by the microprocessor  230 . 
         [0028]    In one embodiment, the accessory  300  has an audio jack  310  and a mono or stereo earphone  340 . In another embodiment, the accessory  300  also has a microphone  350  operatively connected to the audio jack  310 . In another embodiment, the accessory  300  also has an accessory control IC  320  and a secure authenticator  330 . 
         [0029]      FIG. 2  illustrates an exemplary accessory block diagram of an accessory according to various embodiments of the invention. The accessory  300  has a TRRS audio jack  310 , a stereo earphone  340 , a microphone  350 , an accessory control IC  320  and a secure authenticator  330 . The audio jack  310  comprises stereo audio conductors  311  and  312  configured to connect to the stereo earphone  340 , a ground conductor  313 , and a MIC conductor (also referred as MIC line)  314 . The accessory control IC  320  is configured to operatively connect to the MIC conductor  314 , the microphone  350  and the secure authenticator  330 . In another embodiment, the accessory  300  has its own power source, such as an accessory battery to provide power to the secure authenticator  330 . The accessory control IC  320  comprises a MIC switch  328 , a 1-wire control module  322  and an I/O interface  324 . The I/O interface  324  is configured to connect to the MIC conductor  314  via the 1-wire control module  322  and to at least one external I/O port  326  of the accessory  300 . 
         [0030]      FIG. 4  shows a flow diagram according to various embodiments of the invention. In step  410 , communication starts after the jack insertion is detected. The microprocessor  230  is then operatively connected to the MIC line  314  through the audio socket  210  and  12 C interface  220 , and thus able to track the MIC line voltage. The microprocessor  230  is configured to turn on high impedance source (by applying a bias MIC line voltage) in step  420  and to compare the MIC line voltage to a predetermined reference voltage (V Ref ) in step  430 . If the MIC line voltage is no higher than the reference voltage, the accessory communication enters MIC operation in step  440 . If the MIC line voltage is higher than the reference voltage an accessory detection mode in step  450 . In one embodiment, the reference voltage is set a specific voltage level value. In another embodiment, the reference voltage is set as 94% of very low dropout (VLDO) regulator output based on I2C communication PIO level. 
         [0031]      FIG. 5  shows a system state diagram according to various embodiments of the invention. Whenever the electronic device  200  detects any types of audio jack insertion, the electronic accessory communication enters from a dormant state  510  into a JIG detection state  520 . Upon passing the JIG detection, the electronic accessory communication enters an accessory check mode  430 , wherein the microprocessor  230  of the electronic device  200  configures to turn on the MIC line bias voltage and track the MIC line voltage. The microprocessor  230  compares the MIC line to the predetermined reference voltage. Depending on the comparison results and other criteria, the electronic accessory communication enters either a MIC mode  460  (same as the Legacy MIC mode, MIC operation mode or MIC power mode  446 ) or an Accessory mode  470  (same as MIC data mode  444 ). 
         [0032]    During the MIC operation in step  440 , the microprocessor  350  constantly monitors the MIC line voltage and compares the MIC line voltage to the predetermined reference voltage (V Ref ) in step  442  (shown in both  FIG. 4  and  FIG. 6 ). If a first predetermined condition is met, the accessory communication enters into a MIC data mode in step  444 . If a second predetermined condition is met, the accessory communication enters into a MIC power mode in step  446 . The accessory  300  may switch from MIC data mode to MIC power mode if the second predetermined condition is met. Alternatively, the accessory  300  may also switch from MIC power mode to MIC data mode if the first predetermined condition is met. In one embodiment, the first predetermined condition is referred as the MIC line voltage higher than the reference voltage and lasted longer than a first predetermined time period during which the MIC line voltage remains above the reference voltage. In another embodiment, the second predetermined condition is referred as the MIC line voltage lower than the reference voltage and lasted longer than a second predetermined time period during which the MIC line voltage remains below the reference voltage. 
         [0033]      FIG. 8  shows a system operating region diagram according to various embodiments of the invention. If the MIC line voltage is above the reference voltage, then accessory detection mode is activated. In this mode, a clock tracks a first time period during which the MIC line voltage remains above the reference voltage. If the first time period is greater than the first predetermined time period (t COM     —     DEB ), the accessory communication enters a MIC communication mode during which data may be communicated across the audio jack. In certain embodiments, under the MIC communication mode (also referred as MIC data mode), the MIC switch  328  is deactivated (i.e., disconnection between MIC conductor  314  and the microphone  350 ) and the 1-wire control  322  is activated to operatively connect the MIC connector to the external I/O port  326  through the I/O interface  324 . One skilled in the art will recognize that various implementations may be realized within the described architecture all of which fall within the scope of the invention. For example, the I/O port  326  may be used for various external control or communication functions, such as earphone volume up/down, media files forward/backward, etc. 
         [0034]    If the MIC line voltage falls below the reference voltage, the clock is activated to track a second actual time period. When the second actual time period is greater than a second predetermined time period (t PWR     —     DEB ), the accessory communication enters a MIC operation mode (also referred as MIC power mode) wherein the microphone  350  is operated to collect audio signal and transfer the collected audio signal to the electronic device  200 . In certain embodiments, the MIC operation mode activates the MIC switch  328  and connects the MIC conductor  314  to the microphone  350 . The 1-wire control  322  is in a sleep state to operatively disconnect the MIC connector to the external I/O port  326  through the I/O interface  324 . 
         [0035]    The accessory  300  may set the MIC line at high impedance that indicates its readiness for MIC communication mode or load the MIC line to indicate its readiness for exiting communication. The electronic device  200  may control the MIC supply with proper impedance (by setting desired bias MIC line voltage) for each operation mode and start or end the MIC communication mode if the predetermined MIC line condition for entering or leaving the MIC communication mode is met. 
         [0036]    One skilled in the art will recognize that the above-described 1-wire communication mode is only one communication example. In another embodiment, a modulation AC operated above audible frequency may be adopted to superimpose the data line over the power line for MIC line data communication. In another embodiment, the accessory control IC  320  is configured to have the MIC switch to disconnect from the MIC signal coming from the microphone  350  such that the MIC data communication could use any frequency signal even in an audible frequency. 
         [0037]      FIG. 7  illustrates a block diagram when the accessory is in an accessory mode according to another embodiment of the invention. An authentication check is done first on the accessory  300  with the operation of the secure authenticator  330  within the accessory and/or an authentication protocol  260  within the electronic device  200 . If the authentication check is not passed, the accessory will enter a dormant mode without any further communication with the electronic device. If the authentication check is passed, the accessory  300  will get another accessory type check. Depending on the accessory type check based on drainage power level, the accessory  300  may operate in a high power accessory L_R data mode as a high power accessory using L/R Audio line (stereo audio conductors  311  and  312 ), or operate in a low power accessory MIC data mode as a low power accessory using MIC line. Alternatively the accessory  300  may operate in a MIC mode. Under MIC mode, the accessory may further operate in a MIC data mode or MIC power mode depending on the comparison between the MIC line voltage and the reference voltage, as described in the foregoing description. 
         [0038]    The foregoing description of the invention has been described for purposes of clarity and understanding. It is not intended to limit the invention to the precise form disclosed. Various modifications may be possible within the scope and equivalence of the application.