Abstract:
A wireless communication terminal has a user exchangeable cover part. The wireless communication terminal and user exchangeable cover part are electrically interconnected by means of an electrical connector. The user exchangeable cover part comprises identification means. The user exchangeable cover part has an electric circuitry for supporting a user interface of the wireless terminal. The wireless terminal identifies the user exchangeable cover part by detecting the identification means. The wireless terminal operates the electric circuitry of the user exchangeable cover part independently of the identification of user exchangeable cover part.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention relates to a functional cover for use with a wireless terminal, such as a cellular phone. Such covers include functionality that is implemented by adding electronics to the cover. The invention furthermore relates to the mechanical and the electrical interface between a functional cover and a wireless terminal.  
       SUMMARY OF THE INVENTION  
       [0002]     According to a first aspect of the invention a method is provided for operating an electric circuitry included in an exchangeable cover part for supporting a user interface of said wireless terminal. The wireless communication terminal and said user exchangeable cover part are electrically interconnected by means of an electrical connector having connector pins, and the method includes identification of the type of said user exchangeable cover part, and operating at least one of the connector pins in an identification state for sensing a value included in the identification means, and afterwards in an operation state for operating the electric circuitry of the user exchangeable cover part. Hereby the wireless terminal is able to identify the type of the cover in a booting routine and afterwards to operate the cover according to this. The cover may have special illumination effect, special game keys, special sound keys, special memories for playing music or playing games.  
         [0003]     Preferably the connector has a plurality of pins, and at least one of said connector pins is operated in an identification state for sensing a resistor value included in the identification means, and afterwards in an operation state for operating the electric circuitry of said user exchangeable cover part.  
         [0004]     According to a preferred embodiment of the invention, the operation state is a frequency mode for directing an electrical representation of a ringing signal to the electric circuitry for providing an illumination effect following the ringing signal.  
         [0005]     According to a further aspect, the invention relates to a wireless communication terminal having a user exchangeable cover part, wherein the wireless communication terminal and the user exchangeable cover part are electrically interconnected by means of an electrical connector. The user exchangeable cover part comprises identification means, and an electric circuitry for supporting a user interface of the wireless terminal. The wireless terminal identifies the user exchangeable cover part by detecting the identification means; and the connector includes a plurality of connector pins, where at least one of the connector pins is operated in an identification state for sensing a value included in the identification means, and afterwards in an operation state for operating the electric circuitry of the user exchangeable cover part.  
         [0006]     Preferably, the connector includes a plurality of connector pins arranged in line in an equal distance. Advantageously, the connector pins are arranged at the rear side of the cover part. According to a preferred embodiment of the invention the number of connector pins is three. According to a further embodiment of the invention the number of connector pins is five.  
         [0007]     Preferably, at least one of said connector pins is operated in an identification state for sensing a resistor value included in the identification means, and afterwards in an operation state for operating the electric circuitry of said user exchangeable cover part.  
         [0008]     In one implementation of the invention, the operation state is a frequency mode for directing an electrical representation of a ringing signal to the electric circuitry for providing an illumination effect synchronised with the ringing signal.  
         [0009]     In a further aspect of the present invention the user exchangeable cover part may comprise one or more keys adapted to play at least one sound, the one or more keys being connected to the electric circuitry of the user exchangeable cover. The one or more keys may be mapped to a set of tones and/or sound effects, which set of tones and/or sound effects may comprise Music Instrument Digital Interface (MIDI) tones ( ). The keys may be adapted for sound creating purposes, which may comprise music composing applications, sound creating applications, gaming, ring tone creation, system sound creation, sending sounds with Multimedia Messaging Service (MMS) or other messaging services, or any combination thereof.  
         [0010]     According to a further aspect of the invention a user exchangeable cover is provided for releasable attachment to a wireless communication terminal, the user exchangeable cover has an electrical connector part for being electrically connected to the wireless communication terminal in attached position. The user exchangeable cover comprises identification means, and an electric circuitry for supporting a user interface of the wireless terminal. The connector part includes a plurality of connector holes, where at least one of said connector holes is adapted to allow the wireless terminal to operate the user exchangeable cover in an identification state for sensing a value included in the identification means, and afterwards in an operation state for operating the electric circuitry of said user exchangeable cover part.  
         [0011]     The user exchangeable cover part may comprise one or more keys adapted to play at least one sound, the one or more keys being connected to the electric circuitry. The one or more keys may be mapped to a set of tones and/or sound effects, which set of tones and/or sound effects may comprise MIDI-tones. The keys may be adapted for sound creating purposes, which may comprise music composing applications, sound creating applications, gaming, ring tone creation, system sound creation, sending sounds with MMS or other messaging services, or any combination thereof. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     For a better understanding of the present invention and to understand how the same may be brought into effect reference will now be made, by way of example only, to the accompanying drawings, in which:  
         [0013]      FIG. 1  schematically illustrates a preferred embodiment of a wireless telephone according to the invention.  
         [0014]      FIG. 2  schematically illustrates a functional front cover for the wireless telephone shown in  FIG. 1 .  
         [0015]      FIG. 3  schematically shows the essential parts of a wireless telephone for communication with e.g. a cellular network.  
         [0016]      FIG. 4  shows electrical connection between the main block of a wireless telephone and a functional front cover according to preferred embodiments of the invention.  
         [0017]      FIG. 5  shows the connection pad for connecting the wireless telephone and a functional front cover according to the preferred embodiment of the invention.  
         [0018]      FIG. 6  shows the preferred embodiment for the connector part mounted in the functional cover according to the preferred embodiment of the invention.  
         [0019]      FIG. 7  shows schematically in partial cross section the connector part connecting the main block of a wireless telephone and a functional front cover according to the preferred embodiments of the invention.  
         [0020]      FIG. 8  shows a flow chart illustrating the booting and mode selection procedure according to the preferred embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIG. 1  shows a preferred embodiment of a wireless terminal, such as a cellular phone  1 , which comprises a user interface having a keypad  2 , a display  3 , an on/off button  4 , a speaker  5  (only openings are shown), and a microphone  6  (only openings are shown).  
         [0022]     According to the preferred embodiment of the invention the keypad  2  has a first group  7  of keys as alphanumeric keys, two soft keys  8 , and a scroll-key  10  (up/down) for moving a cursor in the display. Furthermore the keypad includes two call-handling keys  9  for initiating and terminating calls. The present functionality of the soft keys  8  is shown in a separate field in the bottom of the display  3  just above the soft keys  8 .  
         [0023]     The cellular phone  1  has an exchangeable functional front cover  25 . An exchangeable front cover is intended to be changed by the user himself without use of tools. Such an exchangeable front cover is disclosed in U.S. Ser. No. 09/503595 filed by the applicant, and this disclosure is hereby incorporated by reference.  FIG. 2  shows the exchangeable functional front cover  25  according to the invention.  
         [0024]      FIG. 2  schematically shows the most important parts of a preferred embodiment of the phone, said parts being essential to the understanding of the invention. A processor  18 , which supports the GSM terminal software, also controls the communication with the network via the transmitter/receiver circuit  19  and an antenna  20 .  
         [0025]     The microphone  6  transforms the user&#39;s speech into analogue signals; the signals formed thereby are A/D converted in an A/D converter (not shown) before the speech is encoded in an audio part  14 . The encoded speech signal is transferred to the processor  18 . The processor  18  also forms the interface to a RAM memory  17   a  and a Flash ROM memory  17   b,  a SIM card  16 , the display  3  and the keypad  2  (as well as data, power supply, etc.). The audio part  14  speech decodes the signal, which is transferred from the processor  18  to the earpiece  5  via a D/A converter (not shown).  
         [0026]     Furthermore a clock generator  24  supplies a clock signal to the processor  18 . The processor  18  is via a three or five wire bus and a connector  41 ,  42 ,  44  connected to electronics  46  in the functional cover  25 .  
         [0027]     A functional cover  25  is a cover for a wireless terminal  1 , which includes functionality that is implemented by adding electronics  46  to the cover  25 . To give some examples, it may include an application reacting e.g. to the power supply or ringing tone. It can also be an application that provides input to the phone (e.g. touch pad).  
         [0028]     The interface between the functional cover and the phone will be described. Five different modes will be introduced, out of which three are very simple and can be used for e.g. sensor applications. The remaining two modes are the generic asynchronous serial bus and a mode based on a synchronous data protocol.  
         [0029]     The objective of the invention is not to provide a full specification of all the different operation modes, but to allow functional covers and transceivers to interact, even through all the modes are not supported by both parts.  
         [0030]     According to the preferred embodiment of the invention the connector includes three connector pins, a positive power supply voltage pin (V DD ), a negative power supply voltage pin (V SS ) and a Cover Type Indicator pin (CTI).  
         [0031]     Preferably the CTI-pin (Cover Type Indicator) is a bi-directional and bi-mode (analogue/digital) signal pin. The CTI-pin is used for a frequency mode, a PWM-mode and a CTI-mode.  
         [0032]     According to an alternative embodiment of the invention the connector includes five connector pins. As for the first embodiment, the connector includes a positive power supply voltage pin (V DD ), a negative power supply voltage pin (V SS ), and a Cover Type Indicator pin (CTI). Furthermore the connector includes a Data Signal pin and a Clock Signal pin.  
         [0033]     The Data Signal pin is used for asynchronous data in data mode and in a synchronous data mode. The protocol for the synchronous data mode may be according to the I2C-Bus Specification, version 2.1, January 2000. The Clock Signal pin is used for the clock in synchronous data mode.  
                                 TABLE 1                           Functional cover interface pins                Output               Pin   type   Description   Communication direction               Vdd       Power supply   Transceiver to Functional                   cover       Vss       Ground   Transceiver to Functional                   cover       CTI   Analogue   Frequency output   Transceiver to Functional                   cover           Digital   PWM output   Transceiver to Functional                   cover           Analogue   Cover Type   Functional cover to               Indicator   Transceiver           Digital   PWM input   Functional cover to                   Transceiver       Data   Digital   Asynchronous data   Transceiver to Functional               output   cover           Digital   Synchronous data   Transceiver to Functional               output   cover           Digital   Asynchronous data-   Functional cover to               input.   Transceiver           Digital   Synchronous data   Functional cover to               input   Transceiver       Clock   Digital   Clock output   Transceiver to Functional                   cover           Digital   Clock input   Functional cover to                   Transceiver                  
 
         [0034]     According to the invention, a baseband engine and a functional cover do not have to support all the modes. This means that the physical interface may comprise from three to five pins depending on the number of supported modes.  
         [0035]     If the BB engine supports multiple modes, passive mode is not allowed to affect the active mode. This means for example, when making the CTI measurement, other pins driving the CTI-pin must have high impedance. Furthermore the baseband engine must be able to drive R CTI .  
         [0036]     When the wireless terminal  1  is switched on, or the processor  18  detects that a new functional cover has been attached to the transceiver part, a boot sequence is initiated. During the boot, the type of the cover is detected via the CTI signal. According to that information, the corresponding data mode is selected and the appropriate power supply level, V dd , is supplied. An example of the boot sequence and mode determination process is presented in  FIG. 8 .  
         [0037]     First the power is switched on to the phone in step  100 . Then the size of the CTI-resistor, R CTI , is measured in step  101 . If the resistor measurement result in step  102  does not exceed a predetermined value (e.g. 750 kOhm), the functional cover is deemed to be attached and a further investigation in order to identify the cover, has to be done. If the resistor measurement result in step  102  exceeds the first predetermined value, the functional cover is deemed to be present. The booting in step  103  has to be continued under the presumption that the cover does not support the electric interface according to the invention.  
         [0038]     If the processor  18  in step  104 , identifies that the cover is “intelligent”, this means that the cover  25  has an asynchronous or synchronous data interface, further information will be exchanged via the digital interface in step  105 . The digital interface and the power scheme have to be defined. Hereafter the booting with be continued in step  106 .  
         [0039]     If the cover in step  104  is deemed not to be “intelligent”, the CTI-resistor, R CTI , is compared with a second threshold (e.g. 64.9 kOhm) and a third threshold (e.g. 93.1 kOhm), the cover  25 , is deemed to have passive components only, and these components are powered by the power supply of the wireless terminal  1 . The voltage is determined by the processor  18  in step  108  by means of a look-up table. The booting is continued in step  109 .  
         [0040]     If the CTI-resistor, R CTI , falls outside the interval defined by the second and the third threshold, the cover  25  is deemed to be able to perform other modes as a pulse mode, a PWM mode or a frequency mode. The mode and power scheme are determined by the processor  18  in step  110  by means of a look-up table. The booting is continued in step  111 .  
                             TABLE 2                           mode supported in dependence of the impedance R CTI .                Mode   R_CTI value                       Synchronous data mode    2.00 kOhm           Asynchronous data mode    6.65 kOhm           PWM data mode   30.90 kOhm               45.30 kOhm               64.90 kOhm           CTI data mode   93.10 kOhm               137.0 kOhm           Freq. data mode   210.0 kOhm               357.0 kOhm               750.0 kOhm           NO COVER   ∞                      
 
         [0041]     Table 2 above describes the CTI resistor value R CTI  vs. functionality conversion. The whole conversion range is preferably divided into a predetermined number of different sub-ranges. For the “intelligent” modes (synchronous and asynchronous), only one resistor value has been reserved, since all the needed additional information can be transferred via the interface. For PWM- and CTI-modes, two resistor values are reserved and for the Frequency-mode, four resistor values have been reserved.  
         [0042]     The power control scheme is based on the CTI-information, which is defined in the table 2. The electrical parameters of the power supply include the power supply voltage VDD, the output current IDD. The output impedance ZOUT of the wireless terminal is 1, and the power on time and power off time.  
         [0000]     Data Interface Synchronous Mode (Data and Clock Pins)  
         [0043]     The data specification used according to the invention may be a sub set of I2C-bus specification version 2.1, January 2000, by Philips Semiconductors. In the synchronous data mode the data pin is used for transferring data between the wireless terminal  1  and the functional cover  25 , usually under control of the processor  18  and the clock oscillator  24  associated therewith.  
         [0000]     Data Interface Asynchronous Mode (Data Pin)  
         [0044]     Data is transferred in the asynchronous data mode based on an asynchronous half-duplex signal. The power supply may be in the level of V DD =2.7V with a data rate of up to 230 kbps.  
         [0045]     The asynchronous data mode as well as the synchronous data mode may be used for loading data from multi-media memory card (MMC) like memories included in the functional cover  25  into the wireless terminal for being handled by means of the processor  18 . Such a data connection may be used for loading data from multi-media memory card (MMC), like memories included in the functional cover  25 , into the wireless terminal for being handled by means of the processor  18 . These data may include, e.g. MP3 music files and executable games. Hereby it has become possible to provide a gaming cover, perhaps having an extra joystick, whose operation is sensed by the gaming cover and transferred to the wireless terminal via the data pin. The game may also be run on an extra processor included in the functional cover  25 , but using the display  3  of the wireless terminal  1 . Extra UI units as a touch sensitive pad/screen or an extra display may be provided on the functional cover  25  and controlled by the processor  18 .  
         [0046]     Alternatively, the functional cover  25  is adapted for a music composer application or any sound creating application designating keys to be assigned to tones and/or sound effects. A default mapping between the keys and a set of tones and/or sound effects is provided. However, a user is enabled to select a number of tones and/or sound effects, and to map these tones and/or sound effects to the keys. Repeated tone, fading tone or any other sound may be mapped to e.g. pressing a key for a particular long period of time or pressing a key together with a shift key. The tones and/or sound effects comprise sounds provided by the wireless terminal  1 , and/or MIDI-tones.  
         [0047]     The MIDI protocol is an entire music description language in binary form. Each word describing an action of musical performance is assigned a specific binary code. The protocol also includes percussion oriented actions. To sound a note in MIDI language a “Note On” message is sent, and then a note “velocity” is assigned, which determines how loud the note is played. Other MIDI messages include selecting which instrument to play, mixing and panning sounds, and controlling various aspects of electronic musical instruments. Normally, a wave table comprising available sounds is used for sound creation according to the MIDI music description. While MIDI is musical performance information, the term MIDI-tones is here the audio output from the entire MIDI system.  
         [0048]     Further, the functional cover  25  comprises memory and processing capabilities so as to provide an ability to create sounds. The memory may comprise wave tables, sound clips, or any other sound information required by said music composer application or sound creating application. Processing capabilities are needed for audio processing. Processing capabilities and memory may be located in the functional cover  25 , in the wireless terminal  1 , or any combination thereof.  
         [0049]     The sound creating capabilities are used for music composing applications, sound creating applications, gaming, ring tone creation, system sound creation, sending sounds with MMS (Multimedia Messaging Service) or other messaging service, or any combination thereof.  
         [0000]     PWM Data Mode (Via CTI-Pin)  
         [0050]     Data is transferred using bi-directional CMOS level PWM-modulated CTI-signal. The power supply may be in the level of V DD =2.7V. The pulse signal may have a variable frequency up to 32 kHz. The pulse duty cycle may be varied between 0.01 and 1. This is an analogue signal in digital format, whereby a sound can easily be transferred ref. buzzer signal.  
         [0000]     CTI Data Mode (Via CTI-Pin)  
         [0051]     The type information of the cover is given in the CTI. I.e. the processor  18  detects the value of the pull down resistor during the start-up (boot) of the phone and selects the right data and power interface mode according to the predefined table.  
         [0052]     This mode is very applicable for applications that do not need any stimulus from the wireless terminal. A flashlight is a good example of such an application.  
         [0000]     Frequency Mode (Via CTI-Pin)  
         [0053]     In the frequency mode, the functional cover  25  is controlled with the frequency of the CTI-signal. Amplitude information is not needed. Therefore the driving signal can be a small analogue voltage, which is then amplified in the cover end. The frequency signal may according to the preferred embodiment be variable up to 10 kHz.  
         [0054]     This mode can be used to direct a ringing tone to the functional cover  25 . Once there, it can be used as a stimulus, for example driving a “light organ”.  
         [0055]     The connector interface may comprise three to five pins and associated pads. The electrical requirements for different signal pins will probably be quite different. The CTI-pin will be used for low, whereas clock and data will be used for medium bandwidth communication. For high bandwidth communication something more sophisticated is needed. As a result, the connector has to be designed with a view to optimising the connector with regard to performance and cost.  
         [0056]     The interface on the wireless terminal comprises three to five signal pads for interacting with a similar amount of pogo pins  41 , which are included in the cover  25 .  
                                         TABLE 3                           Pin order and pad sizes                Pin name   Pin no   A   D   Unit                       CTI   1.   4.3   2   mm           V SS     2.           V DD     3.           Data   4.           Clock   5.                      
 
         [0057]     The order of the pins appears from  FIGS. 4 and 5 . The pins  41  are arranged in a line in equal distance, A. The diameter, D, of the five pads  44  is substantially greater than the diameter of the plungers  42  of the pins  41  in order to ensure a reliable connection.  
         [0058]     It shall be noted that the wireless terminal  1  may have five pads  44 . If the functional cover does not support the data modes, only three pins  41  are needed, and these three pins  41  engage the pad  44  corresponding,to pins no  1 - 3 .  
         [0059]     The connector according to the preferred embodiment of the invention comprises three Pogo-pins  41  (spring-loaded contacts) mounted on a rigid Printed Wiring Board  40 .  
         [0060]     The pogo-pins  41  are mechanically fixed and soldered on the Printed Wiring Board  40  in order to maintain safe and low resistance contact between the phone&#39;s main Printed Wiring Board and Functional Cover&#39;s small rigid Printed Wiring Board  40 . A plunger  42  travel should be at least 1 mm, and the pressure force between plunger and main Printed Wiring Board&#39;s pads should be minimum 25 g for use in a standard wireless terminal. The pad dimensions and spacing are given in table 4 above.  
         [0061]     Pins may advantageously be gold-plated, and their internal resistance has to be specified according to the application. Preferably the internal resistance does exceed 100 mΩ even after 10,000 cycles.  
         [0062]      FIG. 7  shows the wireless terminal  1  with the front cover  25  lifted. The pads  44  are arranged on the printed wiring board  43  of the terminal. The printed wiring board  43  is covered by a light guide  45  of transparent plastic, which has openings allowing the con-nector pins  41 , 42  to access the pads. The connector pins  41 , 42  are mounted on a printed wiring board  40 .  
         [0063]     The printed wiring board  40  is mounted on the inner side of the cover  25  by means of snap coupling means  48 . On the rear side of the printed wiring board  40  an electric circuitry is provided including e.g. three LED&#39;s  47  illuminating respective pipe formed light-guides  49 . In, the frequency mode an electrical representation of a ringing signal is directed to the electric circuitry for providing an illumination effect following the ringing signal. The light-guides  49  may be illuminated individually in a tempo following the ringing signal. This gives an exciting effect for the user when the functional cover  25  is partly transparent.