Abstract:
The present invention provides an electronic device comprising: —a position sensor ( 102; 302; 502 ), —a first integrated circuit component ( 106; 306; 506 ) coupled to the position sensor for acquisition of position data ( 112; 312 ), —a memory ( 114; 314 ) for storing the position data, a second integrated circuit component ( 108; 308 ), wherein the first integrated circuit component comprises means ( 110; 348 ) for signalling the acquisition of the position data to the second integrated circuit component, the second integrated circuit component comprising means ( 108; 364, 374 ) for reading the position data from the memory in response to the signalling.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of position detection, and more particularly to an electronic device such as a computer, a mobile phone, a personal handy phone system (PHS), a personal digital assistant (PDA), a mobile telecommunication device, a navigation system, an electronic organizer or another portable electronic device. 
     BACKGROUND AND PRIOR ART 
     Various position sensor technologies are known from the prior art including resistive and capacitive touch screens and inductive position sensors. 
     EP 0 259 894 B1 shows an inductive position detecting apparatus having a plurality of loop coils for sending and receiving electromagnetic signals and a position pointer having a tuning circuit. The position detection is performed by electromagnetic coupling. Similar inductive position sensing devices are known from EP 0307667 B1; U.S. Pat. No. 6,485,306 B1; U.S. Pat. No. 5,600,105; U.S. Pat. No. 6,667,740 B2. 
     Various capacitive pen entry position sensors are known from U.S. Pat. No. 5,488,204; U.S. Pat. No. 5,942,733 and U.S. Pat. No. 6,380,929. 
     The present invention aims to provide an improved electronic device having an position sensor, an improved integrated circuit component for coupling to a position sensor and an improved integrated circuit component for reading position data as well as corresponding methods and computer program products. 
     SUMMARY OF THE INVENTION 
     The invention provides an electronic device having a position sensor and a first integrated circuit component coupled to the position sensor for acquisition of position data. The electronic device has a memory for storing the position data and a second integrated circuit. The first integrated circuit comprises means for signalling an acquisition of the position data to the second integrated circuit and the second integrated circuit has means for reading the position data from the memory in response to the signalling. 
     The present invention is particularly advantageous for application to battery powered portable devices. In particular, the present invention facilitates to reduce the processing load of the second integrated circuit as the second integrated circuit reads the position data only in response to the signalling data. It is therefore not required that the second integrated circuit permanently reads the memory that receives the position data. As a consequence the power consumption of the second integrated circuit can be reduced which extends the battery lifetime. 
     In accordance with an embodiment of the invention the position sensor has a touch screen or a touch pad. For example, a resistive, capacitive or inductive touch screen or touch pad is utilized. 
     In accordance with an embodiment of the invention the position sensor has at least one conductor for electromagnetic coupling with an entry pen. The conductor is energized periodically in order to send an electromagnetic signal to the entry pen. The entry pen returns an electromagnetic signal that is received by the conductor in order to provide a position signal. 
     In accordance with an embodiment of the invention the position sensor is fixed behind a display, such as the display of a telecommunication device, personal digital assistant, navigation system or other portable electronic device. 
     In accordance with an embodiment of the invention the first integrated circuit component has analogue circuitry for driving the position sensor and logic circuitry for processing the position signal in order to provide position data. 
     In accordance with an embodiment of the invention, the first integrated circuit component has control means for periodically performing acquisitions of position data and generator means for providing an identifier for each position data set. The identifier is written to a predetermined memory location as well as the position data set. Preferably, the memory is overwritten with each new position data acquisition. The identifier value can be a counter value whereby the counter is incremented or decremented with each acquisition scan to obtain up-to-date position data. 
     In accordance with an embodiment of the invention the first integrated circuit component sends an interrupt to the second integrated circuit component in order to signal acquisition of new position data. The second integrated circuit component can use an interrupt handling routine in order prioritize the processing of the interrupts, including interrupts received from other applications. 
     In accordance with an embodiment of the invention the second integrated circuit component sequentially reads a first predetermined memory location that is assigned to the identifier of the position data set, a second memory location that is assigned to the position data set and again the first memory location. If the identifiers that are read from the first memory location are identical this implies that the position data set is valid. Otherwise this indicates that the first integrated circuit component has performed a write operation of newly acquired position data into the memory while the second integrated circuit component has performed the read operation. In order to obtain valid position data, the second integrated circuit component can retry the read operation to read valid position data from the memory after a failed read attempt. 
     In accordance with an embodiment of the invention, the first and second integrated circuit components are coupled by means of a data bus, such as an SPI, IIC and/or UART bus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following preferred embodiments of the invention will be described in greater detail, by way of example only, making reference to drawings in which: 
         FIG. 1  is a block diagram of a first embodiment of an electronic device, 
         FIG. 2  is a flow chart illustrating a preferred mode of operation of the electronic device of  FIG. 1 , 
         FIG. 3  is a block diagram of a portable electronic device, 
         FIG. 4  is a flow diagram showing a preferred mode of operation of the portable electronic device of  FIG. 3 , 
         FIG. 5  is a perspective view showing an embodiment of the configuration of the position detecting system of the portable electronic device of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an electronic device  100  that has a position sensor  102  for providing a position signal  104  to an integrated circuit A  106 . The integrated circuit A 106  is coupled to an integrated circuit B  108 . The integrated circuit A  106  has a position signal processing component  110  for processing the position signal  104 . The position signal processing component  110  provides position data  112  as a result of its processing of the position signal  104 . The position data  112  is written into a memory  114 . Preferably the memory  114  forms an integral part of the integrated circuit  108 . 
     The integrated circuit B  108  is coupled to a memory  116 . Preferably the memory  116  forms an integral part of the integrated circuit B  108 . The memory  116  serves for storage of the position data  112 . The integrated circuit B  108  serves for execution of a program, such as an application program or an operating system that requires the position data  112 . 
     In operation the position sensor  102  provides a position signal  104  to the integrated circuit A  106 . The position signal  104  is processed by the position signal processing component  110 . The resultant position data  112  is written into the memory  114 . 
     Further, the position signal processing component sends position data signalling information  120  to the integrated circuit B  108  after acquisition of the position data  112 . In response to the position data signalling information  120  the integrated circuit B  108  can send a read request  122  in order to read the position data  112  from the memory  114 . In response to the read request  122  the position data  112  is transferred from the memory  114  to the memory  116  of the integrated circuit B  108 . The position data  112  can be read from the memory  116  by the program  118  for further processing. 
     It is to be noted that the position data signalling information  120  that is sent from the position signal processing component  110  after acquisition of the position data  112  to the integrated circuit B  108  facilitates to reduce the power consumption of the integrated circuit B  108  as it reduces the data processing load of the integrated circuit B  108 . This is due to the fact that the integrated circuit B  108  will only read the position data  112  from the memory  114  after receipt of the position data signalling information  120 . This avoids a need for the integrated circuit B  108  to permanently check the memory  114  for the presence of new position data  112 . 
       FIG. 2  shows a corresponding flow chart. In step  200  the integrated circuit A performs a position data acquisition. The acquired position data is stored in the memory in step  202 . Consecutively or in parallel position data signalling information is sent to the integrated circuit B (step  204 ) in order to signal the availability of up-to-date position data. 
     In response to the position data signalling information the integrated circuit B initiates a read operation in order to read the position data from the memory. The integrated circuit B sends a read request to the integrated circuit A (step  206 ). In response the integrated circuit B receives the position data, i.e. the position data is transmitted from the memory of the integrated circuit A to the integrated circuit B (step  208 ). In the following the integrated circuit B can perform various data processing operations on the basis of the received position data for various purposes (step  210 ). 
       FIG. 3  shows a block diagram of a portable electronic device. Elements of  FIG. 3  that correspond to elements of the embodiment of  FIG. 1  are designated by like reference numerals. 
     The portable electronic device  300  has a position sensor  302  for sensing the position of an entry pen  324 . The entry pen  324  has a side switch  326  that can be operated by a user and a pen tip  328 . The position sensor  302  is located behind a display  330  of the portable electronic device  300 . For example, the display  330  is a liquid crystal display or an organic light emitting diode (OLED) display. 
     The position sensor  302  senses the position of the entry pen  324  relative to the display  330  by electromagnetic coupling. In addition to the position detection, the position sensor  302  receives electromagnetic signals from the entry pen  324  that indicate a switch position of the side switch  326  and/or whether the pen tip  328  is depressed or not. Alternatively or in addition the position sensor  302  can receive electromagnetic signals from the entry pen  324  that indicate the pressure with which the pen tip  328  is depressed against the external surface of the display  330 . 
     The integrated circuit  306  has analogue circuitry  332  that comprises a transmission component  334  and a reception component  336 . The transmission component  334  and the reception component  336  serve to generate control signals  338  for controlling the transmission of electromagnetic signals from the position sensor  302  to the entry pen  324  and the reception of electromagnetic signals from the entry pen  324  by the position sensor  302 . The resultant position signal  304  that carries the position information is received by the reception component  336 , which provides the sampled position signal  304  to the position signal processing component  310 . 
     The position signal processing component  310  belongs to logic circuitry  340  of the integrated circuit  306 . In the preferred embodiment considered here, the position signal processing component  310  is provided by a set of instructions of the firmware  342  which is executed by the logic circuitry  340 . 
     In addition, the firmware  342  has a position sensor control component  344  which is a set of firmware instructions for controlling overall operation of the position sensor  302  and the analogue circuitry  332 . Further, the firmware  342  has a generator component  346  which is a set of firmware instructions for generating an identifier for each position data set that is provided by the position signal processing component  310 . The interrupt component  348  is a set of firmware instructions for generating an interrupt  320  when a new acquisition scan of the position data is performed. 
     Further, the integrated circuit  306  has a memory  312 . The memory  312  has a predefined memory location  350  for storing the identifier of a position data set. The memory  312  has predefined memory locations  352 ,  354 ,  356 ,  358  and  360 . These memory locations  352  to  360  serve for storage of a complete position data set. 
     A complete position data set can consists of a sensed x-position and y-position of the entry pen  324 , pressure data indicative of the pressure with which the pen tip  328  of the entry pen  324  is depressed against the display  330 , a pen tip up/down bit indicating whether the pen tip  328  is depressed against the display  330  or not, and pen side switch information indicating the position of the side switch  326  of the entry pen  324 . 
     The memory location  352  is permanently assigned to the x-position, the memory location  354  is assigned to the y-position, the memory location  356  is assigned to the pressure data, the memory location  358  is assigned to the pen tip up/down bit, and the memory location  360  is assigned to the pen side switch information. In other words the memory  312  has a memory mapped area where each component of a position data set and the identifier of the position data set is always stored on a predefined memory location. 
     The integrated circuit  306  has a bus interface  362  for sending a position data set  312  and its identifier to an integrated circuit  308 . The integrated circuit  308  has a bus interface  364 . For example, the bus interfaces  362  and  364  connect the integrated circuits  306  and  308  by means of a data bus such as the SPI, IIC and/or UART data busses. 
     The integrated circuit  308  has logic circuitry  366  for execution of various program components. For example, the logic circuitry  366  can serve for execution of a program component  368  for providing a telecommunication functionality, such as a mobile telephony functionality, a program component  370  for providing an electronic organizer functionality, a program component  372  for providing a navigation system, a program component  374  for interrupt handling and/or a program component  376  for providing an operating system. 
     The integrated circuit  308  has a memory  316  for storing the position data set  312 . 
     The portable electronic device  300  has a battery  378  for providing power to the various components of the portable electronic device including the integrated circuit  308 . 
     The display  330  is coupled to the integrated circuit  308 , such as for display of a graphical user interface provided by the program component  376  for the display of various information and user, data related to one or more of the functionalities provided by the program components  368 ,  370  and  372 . 
     The portable electronic device  300  can have an integrated antenna  380  for the telecommunication functionality. Likewise, the antenna  380  can be required for providing a navigation functionality such as for reception of GPS (Global position system) signals. 
     In operation a user of the portable electronic device  300  can input data by positioning the entry pen  324  on the display  330 . In addition, the user can operate the side switch  326  and/or vary the pressure with which the pen tip  328  is depressed against the surface of the display  330  for the input of data. 
     The analogue circuitry  332  is controlled by the position sensor control component  344  to provide control signals  338  to the position sensor  302  for acquisition of a position signal  304 . The position signal  304  is analogue to digital converted and provided to the position signal processing component  310  in order to extract the position data set  312  from the digitized position signal  304 . 
     The generator component  346  provides an identifier for the new position data set  312 . In the preferred embodiment considered here, the generator component  346  is implemented as a scan counter which counts the data acquisitions of position data sets  312  performed by the position sensor control component  344 . With each position data acquisition scan that is performed by the position sensor  302  under the control of the position sensor control component  344  the scan counter is incremented or decremented depending on the implementation. 
     The position signal processing component  310  writes the position data set  312  and the scan number provided by the generator component  346  to the memory mapped area of the memory  314 . In other words, the scan number is written to the memory location  350 , the x-position data to the memory location  352 , the y-position data to the memory location  354 , the pressure information to the memory location  356 , the pen tip up/down bit to the memory location  358  and the pen side switch information to the memory location  360 . 
     When the scan number and the new position data set  312  is written to the memory  314  the interrupt component  348  is invoked in order to generate an interrupt  320  which is sent from the integrated circuit  306  to the integrated circuit  308 . 
     The interrupt  320  is received by the program component  374 . In response a read operation of the memory mapped area of the memory  314  is performed by the integrated circuit  308  by means of its bus interface  364 . For example, the integrated circuit  308  reads the memory mapped area from the memory location  350  to the memory location  360  in sequential order. After these read operations the integrated circuit  308  performs another read operation in order to read the memory location  350  again. If the content of the memory location  350  is the same for both the initial read operation and the read operation after having read the data set  312 , this indicates that the data set  312  is valid. If the contrary is the case, this indicates that the position signal processing component  310  has performed another write operation of a new position data set while the integrated circuit  308  has attempted to read the previous position data set  312 . In the latter case the integrated circuit  308  retries to read the content of the memory mapped area of the memory  314  for reading the consecutive up-to-date position data set  312 . 
     The position data set  312  is stored in the memory  316  of the integrated circuit  308  for access by the program components  368 ,  370  and/or  372 . 
     The program component  374  can prioritize the various interrupts it can receive e.g. from the program components  368 ,  370  and/or  372  and the interrupt  320 . For example, if the user requires to make an emergency telephone call using the telecommunication functionality provided by the program component  368  the respective interrupt that is generated by the program component  368  has a higher priority than the interrupt  320  such that processing of the interrupt  320  is delayed. 
       FIG. 4  shows a corresponding diagram illustrating the operation of the portable electronic device of  FIG. 3 . As shown in  FIG. 4  the operation of the position detection circuitry provided by the position sensor  302  and the integrated circuit  306  and operation of the host processor provided by the integrated circuit  308  is independent and asynchronous. 
     The process  400  performed by the position detection circuitry comprises the following steps: 
     In step  402  a position scan is performed for acquisition of a position data set. In step  404  the scan counter is incremented or decremented. The position signal acquired from the position scan performed in step  402  is processed in step  406  which provides the position data set. The position data set and the scan counter value are stored in a memory mapped storage region (step  408 ). Further, an interrupt is sent to the host processor in step  410  in order to signal the availability of up-to-date position data in the memory mapped storage region. From step  410  the control goes back to step  402  for performance of a consecutive position data acquisition. 
     The process  412  performed by the host processor comprises the following steps: 
     In step  414  the host processor receives the interrupt from the position detection circuitry (cf. step  410 ). In response the host processor reads the scan counter value from the memory mapped storage region (step  416 ). Next, the host processor reads the position data set from the memory mapped storage region (step  418 ). In step  420  the host processor re-reads the scan counter value from the memory mapped storage region. 
     If the scan counter values that have been read in the steps  416  and  420  are identical, this implies that the position data set that has been read in step  418  is valid (step  422 ) and the position data set is provided to an application for further processing (step  424 ). If the contrary is the case, this implies that the position data set was in the process of being overwritten with a new position data set during the read operation performed in step  418 . As a consequence the control goes back from step  422  to step  416  in order to perform a new read attempt of valid position data from the memory mapped storage region. 
       FIG. 5  shows an exemplary configuration of the position detecting circuitry that is used for acquisition of the position data. Elements in the embodiment of  FIG. 5 , that correspond to elements in the embodiments of  FIGS. 1 and 3  are designated by like reference numerals. 
     The position detecting system according to the preferred embodiment considered here includes a position indicator  524  for indicating a position and a position detecting apparatus  502  for detecting the position of the position indicator  524 . 
     The position indicator  524  includes at least one coil and indicates a position. For example, the position indicator  524  includes a coil and a capacitor connected to the coil, in which the capacitor and the coil form a resonance circuit. 
     The position detecting apparatus  502  includes a control unit  544 , a transmission control unit  534  for generating position detecting signals, a transmission circuit  535 , a sensor unit  503  serving as a sensor area, a switching unit  507  for selecting/switching sensor coils, a reception circuit  536  and a coordinate detection unit  510 . 
     The sensor unit  503 , which extends in the plane, includes a transmission coil unit  580  for transmitting position detecting signals for detecting the position of the position indicator  524 ; and a sensor coil unit  582  for receiving position indicating signals indicating the position of the position indicator  524 . The sensor coil unit  582  includes a plurality of sensor coils arranged in the X-directing (X-direction sensor coils) and a plurality of sensor coils arranged in the Y-direction orthogonal to the X-direction (Y-direction sensor coils). 
     The control unit  544  corresponds to the signal transmitting unit, the receiving unit and the position detecting unit; the transmission control unit  534  and the transmission circuit  535  correspond to the signal transmitting unit; the switching unit  507  and the reception circuit  536  correspond to the receiving unit; and the coordinate detection unit  510  correspond to the position detection unit. 
     The control unit  544  controls the position detecting apparatus  502  and also controls the transmission control unit  534 , the switching unit  507 , the reception circuit  536  and the coordinate detection unit  510 . 
     The transmission control unit  534  generates position detecting signals for detecting a position indicated by the position indicator  524  under the control of the control unit  544 . The transmission circuit  535  amplifies the position detecting signals from the transmission control unit  534  and supplies the position detecting signals to the transmission coil unit  580 , which is provided in the sensor unit  503 . Accordingly, the transmission coil unit  580  is driven. The sensor coils are scanned using the switching unit  507  and the reception circuit  536  for position detection by coordinate detection unit  510 . 
     The various components that are required for controlling and driving operation of the position sensor  502  are provided by a mixed analogue/digital application specific integrated circuit  506 , which has a similar design as the integrated circuits  106  and  306  of  FIGS. 1 and 3 , respectively. The components of the integrated circuit  506  related to the storage of position data and interfacing with a host processor are not shown in  FIG. 5  for ease of explanation. 
     LIST OF REFERENCE NUMERALS 
     
         
           100  electronic device 
           102  position sensor 
           104  position signal 
           106  integrated circuit 
           108  integrated circuit 
           110  position signal processing component 
           112  position data 
           114  memory 
           116  memory 
           118  program 
           120  position data signalling information 
           122  read request 
           300  portable electronic device 
           302  position sensor 
           304  position signal 
           306  integrated circuit 
           308  integrated circuit 
           310  position signal processing component 
           312  position data set 
           314  memory 
           316  memory 
           320  interrupt 
           332  analogue circuitry 
           334  transmission component 
           336  reception component 
           338  control signal 
           340  logic circuitry 
           342  firmware 
           344  position sensor control component 
           346  generator component 
           348  interrupt component 
           350  memory location 
           352  memory location 
           354  memory location 
           356  memory location 
           358  memory location 
           360  memory location 
           362  bus interface 
           364  bus interface 
           366  logic circuitry 
           368  program component 
           370  program component 
           372  program component 
           374  program component 
           376  program component 
           378  battery 
           380  antenna 
           502  position detecting apparatus 
           503  sensor unit 
           506  integrated circuit 
           507  switching unit 
           510  coordinate detecting unit 
           524  position indicator 
           534  transmission control unit 
           535  transmission circuit 
           536  reception circuit 
           544  control unit 
           580  transmission coil unit 
           582  sensor coil unit