Patent Publication Number: US-8983371-B2

Title: Mobile wireless communications device provided enhanced switching between active and power saving near field communication (NFC) modes and related methods

Description:
TECHNICAL FIELD 
     This application relates to the field of communications, and more particularly, to mobile wireless communications devices and related methods that use Near Field Communication (NFC). 
     BACKGROUND 
     Mobile communication systems continue to grow in popularity and have become an integral part of both personal and business communications. Various mobile devices now incorporate Personal Digital Assistant (PDA) features such as calendars, address books, task lists, calculators, memo and writing programs, media players, games, etc. These multi-function devices usually allow electronic mail (email) messages to be sent and received wirelessly, as well as access the internet via a cellular network and/or a wireless local area network (WLAN), for example. 
     Some mobile devices incorporate contactless card technology and/or Near Field Communication (NFC) chips. NFC technology is commonly used for contactless short-range communications based on radio frequency identification (RFID) standards, using magnetic field induction to enable communication between electronic devices, including mobile wireless communications devices. These short-range communications include payment and ticketing, electronic keys, identification, device set-up service and similar information sharing. This short-range high frequency wireless communications technology exchanges data between devices over a short distance, such as only a few centimeters. 
     With NFC technology becoming more commonplace, it is now used with portable wireless communications devices in association with other short-range wireless communications, such as a wireless Bluetooth connection. For example, an NFC connection is often used to establish or authenticate a wireless Bluetooth connection, which is in turn used for general data communications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of a Near Field Communication (NFC) system in accordance with an exemplary aspect providing NFC power state switching. 
         FIG. 2  is a front view of an NFC-enabled cellular device which may be used in accordance with an exemplary aspect to implement the NFC power state switching. 
         FIGS. 3 and 4  are exemplary screen prints which may be provided on the display of the device of  FIG. 2  upon implementation of NFC power state switching. 
         FIG. 5 . is a schematic block diagram of an exemplary NFC device of the system of  FIG. 1  shown in greater detail. 
         FIGS. 6 and 7  are flow diagrams illustrating NFC power switching method aspects associated with the system or devices of  FIG. 1 . 
         FIG. 8  is a schematic block diagram of an alternative NFC system in accordance with an exemplary aspect providing synchronized peer-to-peer recognition features. 
         FIG. 9  is a schematic block diagram of an exemplary NFC device of the system of  FIG. 8  shown in greater detail. 
         FIG. 10  is a flow diagram illustrating synchronized NFC peer-to-peer recognition method steps associated with the system or devices of  FIG. 8 . 
         FIGS. 11 and 12  are signal timing diagrams illustrating signal synchronization operations performed by the devices of the system of  FIG. 8 . 
         FIG. 13  is a schematic block diagram of an exemplary mobile wireless communications device providing enhanced NFC power saving mode switching in accordance with another exemplary embodiment. 
         FIGS. 14 and 15  are schematic block diagrams of exemplary alternative embodiments of the mobile wireless communications device of  FIG. 13 . 
         FIG. 16  is a flow diagram illustrating method aspects associated with the system of  FIG. 13 . 
         FIG. 17  is a schematic block diagram illustrating exemplary components of a mobile wireless communications device that may be used in accordance with the systems of  FIG. 1 ,  8 , or  13 . 
     
    
    
     DETAILED DESCRIPTION 
     The present description is made with reference to the accompanying drawings, in which embodiments are shown. However, many different embodiments may be used, and thus the description should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements or steps in alternative embodiments. 
     Generally speaking, a mobile wireless communications device is disclosed herein which may include a portable housing and a near-field communication (NFC) circuit carried by the portable housing and being switchable between a first (e.g., active) active NFC mode and a second (e.g., power saving) NFC mode. The mobile wireless communications device may further include a processor carried by the portable housing and coupled to the NFC circuit and configured to switch the NFC circuit between the active NFC mode and the power saving NFC mode at a first frequency based upon a first triggering event, and switch the NFC circuit between the active NFC mode and the power saving NFC mode at a second frequency lower than the first frequency based upon a second triggering event different than the first triggering event. As such, the mobile wireless communications device may advantageously use the active NFC mode on a continuous basis to expedite recognition and synchronization with other NFC devices, yet still provide power savings at appropriate times based upon the second triggering event. 
     More particularly, the mobile wireless communications device may further include a display carried by the portable housing and coupled to the processor and being switchable between an illuminated mode and a non-illuminated mode. As such, the first triggering event may comprise the display switching to the illuminated mode, and the second triggering event may comprise the display switching to the non-illuminated mode. In addition, the processor may be further configured to switch the NFC circuit at the second frequency after a delay period from the display switching to the non-illuminated mode. 
     Furthermore, the mobile wireless communications device may further include at least one input device carried by the portable housing and coupled to the processor. As such, the first triggering event may comprise an input from the at least one input device, and the second triggering event may comprise exceeding a threshold period since a last input from the at least one input device. By way of example, the at least one input device may comprise at least one input key, an accelerometer, etc. 
     In accordance with one example, the power saving NFC mode may comprise a passive NFC mode. The mobile wireless communications device may further comprise a wireless transceiver carried by the portable housing and coupled to the processor. Also, the processor may be further configured for communicating electronic mail (email) messages. 
     A related method aspect is for using a mobile wireless communications device, such as the one described briefly above. The method may include switching the NFC circuit between the active NFC mode and the power saving NFC mode at a first frequency based upon a first triggering event, and switching the NFC circuit between the active NFC mode and the power saving NFC mode at a second frequency lower than the first frequency based upon a second triggering event different than the first triggering event. 
     Turning now to  FIGS. 1 and 2 , by way of background, NFC is a short-range wireless communications technology in which NFC-enabled devices are “swiped,” “bumped” or otherwise moved in close proximity to communicate. In one non-limiting example implementation, NFC may operate at 13.56 MHz and with an effective range of about 10 cm, but other suitable versions of near-field communication which may have different operating frequencies, effective ranges, etc., for example, may also be used. 
     NFC circuitry draws power when it is searching for other devices or contactless cards/tags in its vicinity. Because of privacy and security concerns, in the case of an NFC-enabled phone, it may be desirable that the device not always respond to a NFC reader that tries to charge/read the virtual card in the phone. Rather, it may be desirable that the NFC device require an action before it turns on the NFC feature and responds to readers. One such action is to require a password to be entered to activate an NFC search/recognition mode. However, entering a password may be inconvenient, time-consuming, or impractical in some circumstances. For example, when a user wants to pay for transit in a crowded subway station, it may not be practical to perform steps such as typing in a password, finding the NFC icon on the device, activating the NFC icon, etc. This problem may be exacerbated if the phone is in a locked mode, adding yet another step to be performed (i.e., unlocking the device) to place the device in the NFC recognition mode. 
     Another approach may be to have a separate or designated key for activating the NFC functionality. However, the space (i.e., “real estate”) required for a separate, designated key to enable an NFC operational or recognition mode may be difficult to come by in many wireless communications devices. That is, with the ever-increasing amount of functionality implemented in such devices, along with the competing desire for smaller form factors, allotting the necessary real estate for such a designated NFC key simply may not be practical. Moreover, the additional cost of providing a designated key on the device may also be a drawback. 
     In accordance with a first aspect, an NFC system  30  illustratively includes an NFC device  31  which advantageously addresses these technical problems. More particularly, in the example embodiment the NFC system  30  illustratively includes a plurality of NFC devices, namely the NFC device  31  and a second NFC device  32 . The NFC device  31  illustratively includes a housing  33 , a power source  34  carried by the housing  33 , one or more input keys  35  carried by the housing  33  and assigned to a designated device function, and an NFC circuit  36  configured to wirelessly communicate using an NFC communications protocol. The NFC device  31  further illustratively includes a processor  37  carried by the housing  33  which is coupled to the power source  34 , the input key  35 , and the NFC circuit  36 . The device  32  may also include similar components to those described herein with reference to the NFC device  31 , but need not in all embodiments. 
     The NFC device  31  as shown in  FIGS. 2 and 5  comprises a mobile wireless communications device (also referred to herein as a “mobile device”) cellular smart phone enabled for NFC communications by the NFC circuit  36 . In this example embodiment, the NFC device  31  illustratively includes an off-hook key  40  (i.e., for initiating a phone call), a return key  42  for escaping a selection or navigating back through a menu, and an on-hook/power key  43 , which may be used for disconnecting a phone call as for turning the NFC device  31  on or off by holding the key down for a designated period of time. As used herein, the term “key” means an input device that is pressed or actuated to initiate a device function or provide an input, including buttons, keypad keys, trackballs, scroll wheels, etc. It should also be noted that a display  38  of the NFC device  31  shown in  FIG. 2  may be a touch screen display, and in such embodiments the input keys  35  used to initiate the NFC operations described herein may advantageously be touch screen keys. 
     Moreover, the NFC device  31  further illustratively includes a cellular transceiver  45  carried by the housing  33  and coupled to the power source  34  and the processor  37 . Furthermore, the processor  37  may also be configured for communicating wireless voice and data via the cellular transceiver  45  via a cellular communications network (represented as a cellular tower  47  in  FIG. 5 ), as will be described further below. By way of example, the data communications may include email messages, as shown in  FIG. 5 , although other data (e.g., Web data, etc.) may also be communicated. Furthermore, in some embodiments the NFC device  31  may in addition (or instead) include other types of wireless communications circuits capable of transmitting voice or other data, such as a wireless LAN, WiMAX, etc., circuit. 
     In the present example, the input key  35  which is used for initiating NFC operations as described further below is a menu key for generating navigation menus on the display  38 . That is, the designated device function of the input (i.e., menu) key  35  is generating navigation menus, and this designated function is typically performed when the input key  35  is depressed once. Other input devices may also be used in some embodiments, such as an audio input device (e.g., microphone), accelerometer, etc. 
     Operation of the processor  37  and the advantageous NFC power state switching features performed thereby will now be described with reference to  FIGS. 6 and 7 . Beginning at Block  60 , the processor  37  is advantageously configured to initiate the designated device function (menu generation in the present example) based upon a first input or manipulation pattern of the input key  35 , at Blocks  61 - 62 . As noted above, this first manipulation pattern comprises a single actuation of the input key  35 , although a first different actuation pattern may be used in other embodiments. Moreover, a different input key may be selected for initiation of NFC operations, such as the on-hook key  43 , a side convenience key designated for a different designated device function, etc. Furthermore, more than one such key may be designated to initiate the same NFC functionality. 
     The processor  37  is further configured to switch the NFC circuit  36  between a higher power state and a lower power state at a first frequency, at Block  63 . More particularly, this operation would correspond to a typical low power mode as specified by the above-described NFC standard materials, in which the NFC circuit  36  cycles on (high power) and off (low power), usually every three seconds. Such power cycling is advantageous because in the high power state, the NFC circuit  36  is configured to generate a radio frequency (RF) field to initiate NFC communications with the other NFC device  32 . To leave this field on continuously in the NFC device  31  where the power source  34  is a battery (as seen in the more detailed view of the NFC device  31  illustrated in  FIG. 5 ) would deplete the battery at an undesirable rate, which is why the low power recognition mode may be used. 
     Yet, a difficulty with the standard low power mode is that three seconds is a relatively long time in terms of NFC communications to wait for device recognition to occur, and may not be practical for some applications which require relatively quick acquisition and recognition. Thus, in some embodiments, the processor  37  may also advantageously be configured to switch the NFC circuit  36  between the higher power state and the lower power state at a second frequency different than the first frequency based upon a second manipulation pattern of the input key  35  different from the first manipulation pattern, at Blocks  64 - 65 , thus concluding the method illustrated in  FIG. 6  (Block  66 ). 
     By way of example, the second manipulation pattern may include multiple (e.g., two) actuations or pressings of the input key  35  in succession, i.e., within a threshold period or window of time (e.g., one second or less). Moreover, the second frequency may be faster than the first frequency, e.g., about one second (or less), which is three times faster than the above-noted first frequency of three seconds. However, in different embodiments the first and second frequencies may take other values besides those example values set forth herein. As such, the NFC device  31  advantageously provides desired NFC device recognition without undue delay, yet while still maintaining power savings from low-power operation. 
     The processor  37  may be further advantageously configured to switch the NFC circuit  36  from the second frequency back to the first frequency based on a repetition of the second manipulation pattern of the input key  35 , at Block  72 ′ ( FIG. 7 ). For example, it may be desirable to switch the NFC device  31  to the second frequency when approaching an NFC tag/reader (e.g., a subway or ticket kiosk, etc.) and quick recognition is required, but to switch back when no longer in proximity of the NFC tag/reader to save power, as well as for security reasons. 
     In this regard, when the second manipulation pattern occurs and power is cycled to the NFC circuit  36  at the second frequency, this may indicate to the processor  37  that the NFC device  31  is in proximate to a trusted NFC device, and therefore the processor  37  may temporarily lessen security requirements when authorizing and communicating with the trusted NFC device. For example, the processor  37  may proceed directly to communicate with the trusted NFC device, and in the case of a “smart poster” NFC device, such as one configured to pass a Uniform Resource Locator (URL), the processor  37  may automatically direct a browser application thereof to the URL without prompting for permission to proceed to the designated location, at Blocks  70 ′- 71 ′. 
     For the same reasons, the processor  37  may be configured to switch the NFC circuit  36  from the second frequency back to the first frequency after a timeout period, at Block  73 ′. In other words, the processor  37  may perform an automatic switching back to the first frequency based upon the timeout condition, in addition to, or instead of, the manual switch back described above (i.e., resulting from the second manipulation pattern being initiated again). 
     Example menus  50 ,  51  that may be generated by the input (i.e., menu) key  35  are respectively shown in  FIGS. 3 and 4 . More particularly, the menu  50  is generated by the processor  37  when the NFC device  31  is in a normal operating mode and the input key  35  is actuated. In some embodiments, if the display  38  is not illuminated, a first actuation may initially illuminate the display, and a subsequent actuation may then generate the menu  50 . The menu options provided by the processor  37  in the menu  50  may vary depending upon the various operations being performed by the device (e.g., the menu generated on a “home” screen will be different than the one generated while an email application is open, etc.). In the illustrated example, upon initiation of the first manipulation pattern the menu  50  includes the following options: move, move to folder, hide, delete, add folder, and switch application. So, in the present example, the menu  50  would be displayed upon a first actuation or pressing of the input key  35 . 
     However, when the second manipulation pattern of the input key  35  is detected, i.e., a double tap or second actuation/pressing of the input key  35 , then the processor  37  causes switching of the NFC circuit  36  based upon the second frequency, which is indicated by an arrow extending from the menu  50  and notation that this NFC operational mode has been enabled for thirty seconds. However, it should be noted that other timeout periods greater or lesser than thirty seconds may be used in some embodiments (e.g., one minute, two minutes, etc.), and in other embodiments the timeout period may not be used at all. 
     Turning to the menu  51 , here the processor  37  generates a menu on the display  38  for enabling initiation of NFC device recognition and communications with the other NFC device  32  upon detection thereof from a “locked” device mode. That is, the menu  51  is generated from the locked mode, meaning that the keypad (whether touch screen or individual buttons) or other convenience keys are disabled by the processor  37 . In some locked modes, the display  38  may be changed to a default image as well (e.g., a blank screen with only a background color/image and no icons). In this case, the menu  51  generated by the processor  37  may advantageously be different than the menu  50 , since there is a relatively small selection of operations that may be performed from the locked mode. So, when in the locked mode and the input key  35  is actuated once, the menu  51  is displayed and illustratively includes the following options: enable NFC for thirty seconds; unlock; emergency call; and cancel. The “enable NFC for 30 s” option is highlighted so that upon a second actuation of the input key  35  this option is automatically selected, again causing the processor  37  to implement switching at the second frequency. While this menu option may also be selected directly on the touch screen display  38 , a second actuation of the input key  35  typically may be performed much easier and faster. 
     The NFC device  31  therefore advantageously provides a relatively convenient and consistent way of enabling the NFC circuit  36  for a short period of time, which may be particularly helpful for applications with relatively low security requirements, or for relatively low-value payment transactions. The above-described implementation further advantageously utilizes an existing input key  35  on the NFC device  31  and provides for relatively easy access to enable NFC communications. 
     A related physical, computer-readable medium may have computer-executable instructions for causing the NFC device  31  to perform steps including initiating the designated device function based upon a first manipulation pattern of the input key  35 , and switching the NFC circuit  36  between a higher power state and a lower power state at a first frequency, as discussed above. Moreover, a further step may include switching the NFC circuit  36  between the higher power state and the lower power state at a second frequency different than the first frequency based upon a second manipulation pattern of the input key  35  different from the first manipulation pattern, again as further discussed above. 
     Turning now to  FIGS. 8-12 , another drawback of the existing NFC lower-power tag detection approach is that it does not work in conjunction with a peer-to-peer NFC mode. In accordance with another advantageous aspect, an NFC system  130  and NFC devices  131 ,  132  advantageously provide a low power operation when in a peer-to-peer operating mode. That is, in the NFC system  130  both devices  131 ,  132  are operational in a peer-to-peer NFC mode. 
     The various components illustrated in  FIGS. 8 and 9  that correspond to those previously discussed above with reference to  FIGS. 1 and 2  are numbered in increments of decades (i.e., the power source  34  is similar to the power source  134 , etc.) for clarity of reference. As such, to the extent these components have already been explained above that explanation will not be repeated here, and the following discussion will accordingly focus on the additional operations performed by such components in accordance with the present example. 
     Beginning at Block  200 , the processor  137  is advantageously configured to synchronize or temporally align an internal timing signal I (i.e., a local timing signal)#to an external timing signal E, at Block  201 . The internal timing signal I is shown initially out of synchronization with the external timing signal E in  FIG. 11 , and  FIG. 12  shown the internal timing signal I′ after synchronization with the external timing signal E. It should be noted that the internal and external signals I, E need not be mirror images of one another to be synchronized as shown in  FIG. 12 , but may be synchronized in the sense that leading or trailing edges are temporally aligned (e.g., the signals could be inverted with respect to one another but still synchronized in time). 
     The internal timing signal I may be generated by the processor  137  using a variety of techniques. Furthermore, the external timing signal E may be obtained from a number of different sources, as seen in  FIG. 9 . For example, the processor  137  may be configured to synchronize the internal timing signal I to a cellular network timing signal as the external timing signal E via the cellular transceiver  145 . In accordance with another option, each NFC device  131 ,  132  may further include a satellite positioning receiver  146  coupled to the processor  137  and configured to receive a satellite positioning system (e.g., GPS, Galileo, GLONASS, etc.) timing signal from one or more satellites  147 , with which the processor  137  is configured to synchronize the internal timing signal to as the external timing signal I. Still another option is that the processor  137  may be configured to synchronize the internal timing signal I to the common external system timing signal E via the NFC circuit  136  (e.g., synchronization to GMT or other accurate time source via NFC communications, etc.). 
     The processor  137  is further configured to cycle power to the NFC circuit  136  to periodically switch the NFC circuit  136  between a peer-to-peer recognition state and a low power state based upon the synchronized internal timing signal I, at Block  202 . When NFC devices are powered up and operating in a peer-to-peer mode, they continuously generate an RF field for recognizing and communicating with other NFC devices. However, because each of the devices  131 ,  132  is synchronized to the same external timing signal and performs the power cycling at the same intervals, they advantageously generate their respective RF fields and perform device recognition at the same times, and thus these devices will be able to “see” each other despite now operating in a power saving mode. 
     Thus, the processor  137  of the device  131  is also advantageously configured to initiate peer-to-peer NFC communications with the other device  132  when in range thereof upon being switched (e.g., simultaneously switched) to the peer-to-peer recognition state therewith, at Blocks  203 - 204 , thus concluding the method illustrated in  FIG. 10  (Block  205 ). As such, the system advantageously addresses the technical problem of providing a relatively low-power NFC peer-to-peer recognition mode, while still providing desired recognition times without undue delay. 
     The processor  137  may further be configured to operate the NFC circuit  136  in an active communication mode in the peer-to-peer recognition state. Furthermore, the processor  137  may be configured to cycle power to the NFC circuit  136  at various time intervals, although an interval of not greater than one second may be desirable, as shorter durations may be particularly beneficial from a rapid recognition standpoint, such as in the range of approximately 200 μs to approximately 600 μs, for example, although other durations may be used in different embodiments. Generally speaking, the interval is balanced to be long enough to provide desired power savings but also quick recognition times. 
     It should be noted that in the system  130 , both NFC devices  131 ,  132  need not be mobile wireless NFC devices. For example, some electronic devices such as televisions, printers, etc., may be enabled with NFC circuitry, but these devices are essentially stationary and typically plugged in to a building power source. As such, while power savings may not be as high a priority for stationary or wall-powered devices, such stationary devices may still operate as described above and be included in the system  130  (or the system  30  in some embodiments) to initiate NFC communications with mobile devices which utilize these techniques to conserve battery power. Moreover, it should also be noted that while two devices are shown in the above-described system  30 ,  130  for ease of illustration, in some embodiments more than two devices may be included in the particular system. 
     A related physical computer-readable medium is also provided and may have computer-executable instructions for causing the NFC device  131  to perform steps including synchronizing an internal timing signal I of the NFC device to an external timing signal E, and cycling power to the NFC circuit  136  to periodically switch the NFC circuit between a peer-to-peer recognition state and a low power state based upon the synchronized internal timing signal I′. A further step may include initiating peer-to-peer NFC communications with another NFC device  132  when in range thereof and upon being simultaneously switched to the peer-to-peer recognition state therewith. 
     Referring now additionally to  FIGS. 13-16 , in accordance with another example embodiment a mobile device  300  illustratively includes a portable housing  301  and an NFC circuit  302  carried by the portable housing. As discussed above, the NFC circuit  302  may be switched between different operating modes, including an active NFC mode, and a power saving mode, such as a passive mode or an unpowered mode. The mobile device  300  further illustratively includes a processor  303  carried by the portable housing  301  that is coupled to the NFC circuit  302 . Beginning at Block  350 , the processor  303  is configured to switch the NFC circuit  302  between the active NFC mode and the power saving NFC mode at a first frequency based upon a first triggering event, at Blocks  351 - 352 , and switch the NFC circuit between the active NFC mode and the power saving NFC mode at a second frequency lower than the first frequency based upon a second triggering event different than the first triggering event, at Blocks  353 - 354 , thus concluding the method illustrated in  FIG. 16  (Block  355 ). By way of example, this may be done by setting the active NFC mode “on” or “burst” time to a given or fixed duration, and changing the power saving NFC mode time between bursts. That is, the processor  303  may cycle the NFC circuit  302  to the active NFC burst mode with longer or shorter power saving NFC mode durations therebetween. Generally speaking, the duration of the active mode pulse should be long enough to recognize a load on the electromagnetic field, such as about 60 μs, although other durations may also be used. 
     Generally speaking, the first triggering event may be an action or operation which indicates that the mobile device  300  is in use. In the example shown in  FIG. 14 , the mobile device  300 ′ includes a display  304 ′, and one triggering event that may indicate the mobile device is in use (i.e., a first triggering event) is when the display is illuminated. Conversely, a second triggering event which is indicative of the mobile device  300 ′ not being in use is when the display  304 ′ is not illuminated, i.e., it is in a non-illuminated or “sleep” mode. By way of example, the first frequency may be five or more times per second, whereas the second frequency may be less than five times a second (e.g., once per second), although other values for these frequencies may also be used in different embodiments. Moreover, subsequent triggers may optionally be used to further decrease the active mode cycling frequency, or turn off the active mode indefinitely in some implementations. 
     In some embodiments the display  304 ′ may be illuminated based upon a key press, etc., even if the display or mobile device  300 ′ is in a locked mode. Other events that may cause the display  304 ′ to be illuminated, or otherwise serve as a first triggering event, include a calendar reminder generated by a calendar application running on the mobile device  300 ′, receipt of a message (e.g., email, SMS, MMS, etc.) via a wireless network, etc. By associating the frequency at which cycling to the NFC power saving mode is performed with the operational state of the display  304 ′, this provides a ready indication that if the display  304 ′ is illuminated, then the NFC circuit  302 ′ is in its fastest NFC acquisition mode. The processor  303 ′ may be further configured to implement a delay period or lag time after the display  304 ′ is switched to the non-illuminated mode. This may advantageously help reduce situations where the display  304 ′ goes into a sleep mode (i.e., the non-illuminated mode) while the NFC circuit  302 ′ is attempting to engage in communications with another NFC device, which may otherwise increase the possibility of not establishing an NFC communications link therewith if the NFC circuit  302 ′ is switched to the slower NFC acquisition mode. Similarly, establishing an NFC communications link may serve as a first triggering event that causes the processor  303 ′ to switch between the active NFC mode and the power saving NFC mode at the first (i.e., faster) frequency. 
     In the example shown in  FIG. 15 , the mobile device  300 ″ illustratively includes two input devices, namely an input key(s)  305 ″ (such as found on a keypad, a convenience key or button, etc., as noted above) and an accelerometer  306 ″. Other examples of input devices may include track balls, touch pads, scroll wheels, biometric sensors, touch screens, etc. With respect to a given input device, the first triggering event may comprise an input therefrom (e.g., key press, movement detection by accelerometer  306 ″, etc.), while the second triggering event may comprise exceeding a threshold period since a last input is received. For example, if the input key  305 ″ is not pressed or no motion is detected by the accelerometer  306 ″ within the threshold period (e.g., ten seconds), then the processor  303 ″ causes the NFC circuit  302 ″ mode cycling to occur at the second, slower rate to thereby conserve power. Other threshold periods may be used, and in some embodiments this threshold may be user-selectable. Further, it should be noted that not all of the input devices on a given mobile device need be used for NFC mode switching purposes in all embodiments, i.e., the NFC mode switching may be associated with one or more input devices in different embodiments. 
     One particular advantage of using an input device for triggering the change in frequency of the NFC circuit  302 ″ power saving mode cycling is that input from a particular key  305 ″ or the accelerometer  306 ″ need not “wake up” (i.e., illuminate) the display  304 ′, which may help provide further power savings if NFC communications may be performed in the background, for example. In such embodiments, a “click” from the key  305 ″ or other feedback may be used to provide a suitable indication that the NFC mode switching frequency has been changed without the need for visual verification on the display  304 ′. With respect to the accelerometer  306 ″, NFC communications typically require “swiping” of another NFC device, and therefore movement of the mobile device  300 ″, may be taken to mean that the device is being carried or transported, making the first NFC mode switching frequency more appropriate, while the second frequency would be more appropriate when the mobile device is at rest. It should be noted that other input devices or sensors may similarly be used to detect when the mobile device  300 ″ is held in a hand or being moved (e.g., infrared (IR) sensor, motion sensor, image (e.g., camera) sensor, etc.). 
     The mobile devices  300 ,  300 ′, and  300 ″ may further include one or more wireless transceivers (e.g., cellular, WiFi, WiMAX, etc.), and the processors  303 ,  303 ′, and  303 ″ may also be configured for communicating email messages, as discussed further above. A non-transitory computer-readable medium is also provided for causing the NFC circuit  302  to switch between the active NFC mode and the power saving NFC mode at a first frequency based upon a first triggering event, and switch between the active NFC mode and the power saving NFC mode at a second frequency lower than the first frequency based upon a second triggering event different than the first triggering event, as discussed further above. 
     Example components of a mobile wireless communications device  1000  that may be used in accordance with an example embodiment are further described below with reference to  FIG. 17 . The device  1000  illustratively includes a housing  1200 , a keyboard or a keypad  1400  and an output device  1600 . The output device shown is a display  1600 , which may comprise a full graphic LCD. Other types of output devices may alternatively be utilized. A processing device  1800  is contained within the housing  1200  and is coupled between the keypad  1400  and the display  1600 . The processing device  1800  controls the operation of the display  1600 , as well as the overall operation of the mobile device  1000 , in response to actuation of keys on the keypad  1400 . 
     The housing  1200  may be elongated vertically, or may take on other sizes and shapes (including clamshell housing structures). The keypad may include a mode selection key, or other hardware or software for switching between text entry and telephony entry. 
     In addition to the processing device  1800 , other parts of the mobile device  1000  are shown schematically in  FIG. 17 . These include a communications subsystem  1001 ; a short-range communications subsystem  1020 ; the keypad  1400  and the display  1600 , along with other input/output devices  1060 ,  1080 ,  1100  and  1120 ; as well as memory devices  1160 ,  1180  and various other device subsystems  1201 . The mobile device  1000  may comprise a two-way RF communications device having data and, optionally, voice communications capabilities. In addition, the mobile device  1000  may have the capability to communicate with other computer systems via the Internet. 
     Operating system software executed by the processing device  1800  is stored in a persistent store, such as the flash memory  1160 , but may be stored in other types of memory devices, such as a read only memory (ROM) or similar storage element. In addition, system software, specific device applications, or parts thereof, may be temporarily loaded into a volatile store, such as the random access memory (RAM)  1180 . Communications signals received by the mobile device may also be stored in the RAM  1180 . 
     The processing device  1800 , in addition to its operating system functions, enables execution of software applications  1300 A- 1300 N on the device  1000 . A predetermined set of applications that control basic device operations, such as data and voice communications  1300 A and  1300 B, may be installed on the device  1000  during manufacture. In addition, a personal information manager (PIM) application may be installed during manufacture. The PIM may be capable of organizing and managing data items, such as e-mail, calendar events, voice mails, appointments, and task items. The PIM application may also be capable of sending and receiving data items via a wireless network  1401 . The PIM data items may be seamlessly integrated, synchronized and updated via the wireless network  1401  with corresponding data items stored or associated with a host computer system. 
     Communication functions, including data and voice communications, are performed through the communications subsystem  1001 , and possibly through the short-range communications subsystem. The communications subsystem  1001  includes a receiver  1500 , a transmitter  1520 , and one or more antennas  1540  and  1560 . In addition, the communications subsystem  1001  also includes a processing module, such as a digital signal processor (DSP)  1580 , and local oscillators (LOs)  1601 . The specific design and implementation of the communications subsystem  1001  is dependent upon the communications network in which the mobile device  1000  is intended to operate. For example, a mobile device  1000  may include a communications subsystem  1001  designed to operate with the Mobitex™, Data TAC™ or General Packet Radio Service (GPRS) mobile data communications networks, and also designed to operate with any of a variety of voice communications networks, such as AMPS, TDMA, CDMA, WCDMA, PCS, GSM, EDGE, etc. Other types of data and voice networks, both separate and integrated, may also be utilized with the mobile device  1000 . The mobile device  1000  may also be compliant with other communications standards such as 3GSM, 3GPP, UMTS, etc. 
     Network access requirements vary depending upon the type of communication system. For example, in the Mobitex and DataTAC networks, mobile devices are registered on the network using a unique personal identification number or PIN associated with each device. In GPRS networks, however, network access is associated with a subscriber or user of a device. A GPRS device therefore typically involves use of a subscriber identity module, commonly referred to as a SIM card, in order to operate on a GPRS network. 
     When required network registration or activation procedures have been completed, the mobile device  1000  may send and receive communications signals over the communication network  1401 . Signals received from the communications network  1401  by the antenna  1540  are routed to the receiver  1500 , which provides for signal amplification, frequency down conversion, filtering, channel selection, etc., and may also provide analog to digital conversion. Analog-to-digital conversion of the received signal allows the DSP  1580  to perform more complex communications functions, such as demodulation and decoding. In a similar manner, signals to be transmitted to the network  1401  are processed (e.g. modulated and encoded) by the DSP  1580  and are then provided to the transmitter  1520  for digital to analog conversion, frequency up conversion, filtering, amplification and transmission to the communication network  1401  (or networks) via the antenna  1560 . 
     In addition to processing communications signals, the DSP  1580  provides for control of the receiver  1500  and the transmitter  1520 . For example, gains applied to communications signals in the receiver  1500  and transmitter  1520  may be adaptively controlled through automatic gain control algorithms implemented in the DSP  1580 . 
     In a data communications mode, a received signal, such as a text message or web page download, is processed by the communications subsystem  1001  and is input to the processing device  1800 . The received signal is then further processed by the processing device  1800  for an output to the display  1600 , or alternatively to some other auxiliary I/O device  1060 . A device may also be used to compose data items, such as e-mail messages, using the keypad  1400  and/or some other auxiliary I/O device  1060 , such as a touchpad, a rocker switch, a thumb-wheel, or some other type of input device. The composed data items may then be transmitted over the communications network  1401  via the communications subsystem  1001 . 
     In a voice communications mode, overall operation of the device is substantially similar to the data communications mode, except that received signals are output to a speaker  1100 , and signals for transmission are generated by a microphone  1120 . Alternative voice or audio I/O subsystems, such as a voice message recording subsystem, may also be implemented on the device  1000 . In addition, the display  1600  may also be utilized in voice communications mode, for example to display the identity of a calling party, the duration of a voice call, or other voice call related information. 
     The short-range communications subsystem enables communication between the mobile device  1000  and other proximate systems or devices, which need not necessarily be similar devices. For example, the short-range communications subsystem may include an infrared device and associated circuits and components, NFC or a Bluetooth™ communications module to provide for communication with similarly-enabled systems and devices. 
     Many modifications and other embodiments will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that various modifications and embodiments are intended to be included within the scope of the appended claims.