Abstract:
The invention relates to a recovery of a hardware module of an electronic device from a malfunction state. The hardware module is connected via a signal line to a recovery component of the device, a state of the signal line being controlled by the hardware module. The recovery component monitors a state of the signal line. Whenever the signal line is detected not to assume a predetermined state during a predetermined period of time, the recovery component causes a hardware reset of the hardware module.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to a method for recovering a hardware module of an electronic device from a malfunction state, to a recovery component for an electronic device, to a corresponding electronic device, and to a corresponding software program product.  
       BACKGROUND OF THE INVENTION  
       [0002]     Many electronic devices comprise a screen which enables a presentation of information to a user of the device.  
         [0003]     Typically, the screen forms a part of a display module, which comprises in addition a display driver. The display driver includes a frame memory storing the data for a current image which is to be displayed on the screen. The presentation on the screen is updated by the display driver position by position with data from the frame memory. The image data for a respective frame is usually provided to the display driver by a host. The host, as the main processing unit of the electronic device, may run applications requiring a presentation of images via the screen.  
         [0004]     The display driver may provide the host with information on the currently updated position of the screen via a signal line, in order to allow the host to synchronize with the display driver. Synchronization is typically employed for critical moving image applications, like game and video applications. The position information can be generated for example from display module internal synchronization signals, in particular from a horizontal and a vertical synchronization signal. The vertical synchronization signal may be valid at the beginning of a frame, and the horizontal synchronization signal may be valid at the beginning of each line. In combination, these signals thus provide information on the current position.  
         [0005]     The signal line may be activated by the display driver, for example, whenever a new frame in a moving image application is needed. In the host, an interrupt is generated from the active signal line, which initiates a Direct Memory Access (DMA) transfer of a further image to the display module.  
         [0006]     Alternatively, the signal line may also be omitted. In this case, the data for a respective frame is transmitted without synchronization from the host to the frame memory.  
         [0007]     The presentation on the screen may be subject to malfunctions. A malfunction can be caused by various external influences, like electrostatic discharge (ESD) pulses, electrical glitches, power shortages, etc.  
         [0008]     External influences may change for example one bit or several bits in control registers of the display module. Further, they may corrupt images which are currently transferred via an internal bus in the display module. Moreover, external influences may stop for example a powering circuit or a timing circuit in the display module. Such disturbances may result in a blank display, in a presentation of corrupted data on the screen, or in a change of mode of the display.  
         [0009]     So far, it is only possible to detect a malfunction of a display by means of a visual check.  
         [0010]     In order to ensure a correct presentation nevertheless, software run by the host typically sends a refresh sequence to the display driver at regular intervals, for example every three seconds. The refresh sequence is used to rewrite all registers of the display module and the image data currently stored in the frame memory.  
         [0011]     A software refresh, however, is not suited to recover a display from all possible malfunctions which may be caused by external influences. For example, if the powering circuit is affected such that it entered an abnormal state, a register refresh by software does not fix the error.  
         [0012]     Such malfunctions in a display module can usually only be removed by rebooting the electronic device or by means of a separate hardware reset of the display driver.  
         [0013]     In contrast to a software refresh, however, a hardware reset is not suited to be performed automatically on a regular basis, because a hardware reset causes visual effects on the screen. If a hardware reset was performed every three seconds, for example, this would result in a blank display every three seconds, which would be annoying to a user.  
         [0014]     It is to be understood that a similar problem may occur with other hardware modules than a display module, if they are subject to external influences.  
       SUMMARY OF THE INVENTION  
       [0015]     It is an object of the invention to enable an improved recovery of a hardware module from a malfunction state.  
         [0016]     A method is proposed for recovering a hardware module of an electronic device from a malfunction state. The hardware module is connected via a signal line to a recovery component of the electronic device, a state of the signal line being controlled by the hardware module. The proposed method comprises at the recovery component monitoring a state of the signal line. The proposed method further comprises at the recovery component causing a hardware reset of the hardware module, whenever the signal line is detected not to assume a predetermined state during a predetermined period of time.  
         [0017]     Moreover, a recovery component for an electronic device is proposed. The proposed recovery component is adapted to be connected via a signal line to a hardware module of the electronic device. The proposed recovery component is moreover adapted to monitor a state of the signal line and to cause a hardware reset of the hardware module whenever the signal line is detected not to assume a predetermined state during a predetermined period of time.  
         [0018]     Moreover, an electronic device is proposed, which comprises a hardware module and a recovery component connected to each other via a signal line. The hardware module is adapted to set the signal line at regular intervals to a predetermined state as long as no malfunction occurs in the hardware module. The recovery component is adapted to monitor a state of the signal line and to cause a hardware reset of the hardware module whenever the signal line is detected not to assume the predetermined state during a predetermined period of time.  
         [0019]     Finally, a software program product is proposed, which stores a software code for recovering a hardware module of an electronic device from a malfunction state. The hardware module is assumed to be connected via a signal line to a recovery component of the electronic device, a state of the signal line being controlled by the hardware module. When running in the recovery component, the software code realizes the steps of the proposed method.  
         [0020]     The invention proceeds from the consideration that a hardware module is able to control the state of a signal line. It may cause a predetermined state of the signal line at regular intervals. It has to be understood that the intervals do not have to have exactly the same length, but they should not exceed a predetermined length. When a malfunction occurs in the hardware module, changing the state of the signal line may be prevented. A non-appearance of the predetermined state of such a signal line for a certain period of time can then be considered as an indication of a malfunction in the hardware module. It is therefore proposed that in case of a non-appearance of the predetermined state of a signal line, a hardware reset of the hardware module is caused.  
         [0021]     It is an advantage of the invention that a malfunction in a hardware module can be detected and eliminated without a repeated software refresh. As a result, the power which is required for the repeated software refreshes is saved. The caused hardware reset results in a more comprehensive recovery than a software refresh. Since the hardware reset is only used when needed, disturbing effects are avoided.  
         [0022]     The hardware module according to the invention can be any hardware module which may suffer from malfunctions, for instance a display module like a liquid crystal display (LCD) module. The electronic device according to the invention can be any device comprising such a hardware module, for example a mobile terminal including an LCD module.  
         [0023]     In some electronic devices, a signal line which is controlled by a hardware module is already implemented. Such a signal line may then be used advantageously in addition for the invention.  
         [0024]     In case the hardware module is a display module, for example, the signal line may be further connected to a frame control portion. The frame control portion is adapted to detect a predetermined state of the signal line as a synchronization signal for providing image data to the display module.  
         [0025]     The hardware module of the invention may be adapted to stop setting the signal line to a predetermined state for various malfunction reasons. Setting the signal line to the predetermined state may be stopped, for instance in case a bit in a control register of the hardware module changed without cause within the hardware module, in case data in an internal bus of the hardware module is corrupted, or in case a powering circuit of the hardware module has been stopped.  
         [0026]     Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not drawn to scale and that they are merely intended to conceptually illustrate the structures and procedures described herein. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0027]      FIG. 1  is a schematic block diagram of an electronic device according to an embodiment of the invention; and  
         [0028]      FIG. 2  is a flow chart illustrating an operation in the device of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]      FIG. 1  schematically presents a mobile terminal as an electronic device, in which a recovery from a malfunction of a hardware module in accordance with an embodiment of the invention is implemented.  
         [0030]     The mobile terminal  1  can be for example a conventional mobile phone, which includes among other components an LCD module  10  as a hardware module and a host  20 .  
         [0031]     The LCD module  10  comprises a screen  11  and a display driver  12 . The display driver  12  may be connected to the screen  11  by an internal bus. The display driver  12  comprises among other components a frame memory  13 , a position control portion  14 , control registers  15  and a powering circuit  16 . The powering circuit  16  is connected to the battery voltage and takes care of providing the components of the LCD module  10  with an appropriate power.  
         [0032]     The host  20  includes among other components a frame control portion  21  and a recovery component  22 .  
         [0033]     The frame control portion  21  is connected via a data bus  31  to an input of the frame memory  13  of the display driver  12 . A signal line  32  moreover connects the position control portion  14  on the one hand with the frame control portion  21  and on the other hand with the recovery component  22 . The recovery component  22  is further connected via an HW reset line  33  with the LCD module  10 .  
         [0034]     A recovery from a malfunction of the mobile terminal  1  due to an external influence, like an ESD pulse, will now be described with reference to the flow chart of  FIG. 2 .  
         [0035]      FIG. 2  illustrates on the left hand side the operation of the LCD module  10  and on the right hand side the operation of the host  20 .  
         [0036]     The host  20  runs an application (not shown), like a game, which requires a presentation of moving images on the screen  11 . The frame control portion  21  of the host retrieves data for the respectively required frame from some memory of the mobile terminal  1  (not shown) and provides it to the LCD module  10  via the data bus  31 . (step  221 )  
         [0037]     The display driver  12  of the LCD module  10  buffers the data of a received frame in its frame memory  13 . The frame is then presented position by position on the screen  11  with data from the frame memory  13  and under control of the position control portion  14 . The position control portion  14  uses to this end a horizontal and a vertical synchronization signal. (step  211 )  
         [0038]     When the update of the screen  11  based on the currently buffered frame data has been completed and no malfunction occurred (step  212 ), the position control portion  14  activates the signal line  32  (step  213 ). To this end, the voltage on the signal line  32 , which is low by default, is temporarily set to a higher value.  
         [0039]     Meanwhile, the frame control portion  21  and the recovery component of the host  20  monitor the signal line  32  (step  222 ).  
         [0040]     The frame control portion  21  considers an active signal line  32  in a conventional manner as a synchronization signal, that is, as an indication that data for a new frame is required in the display driver  12  for updating the screen  11 . Whenever the frame control portion  21  detects an activation of the signal line  32 , it thus provides the data for the next frame to the LCD module  10  (step  221 ). The LCD module  10  continues thereupon updating the presentation on the screen  11 , now based on the new data in the frame memory  13  (step  211 ). Steps  211  through  213  and  221  through  223  are repeated in a loop, as long as no malfunction occurs and as long as a further frame is requested to be presented by the application running in the host  20 .  
         [0041]     In case a malfunction occurs (step  212 ), in contrast, the signal line  32  is not activated any more (step  214 ). The cause of the malfunction may be for example a change of bits in the control registers, a corrupted image on an internal bus or a stopped powering circuit. The malfunction may cause for example a blank display, corrupted data on the screen or a mode change of the display.  
         [0042]     In case the frame control portion  21  does not detect an activation of the signal line  32  within twice the refresh period ( 223 ), the frame control portion  21  omits the frame which is currently to be transferred to the frame memory  13  and waits for a new frame from the running application. Visually, this can be seen as a stuck camera viewfinder or video.  
         [0043]     When the recovery component  22  detects that the signal line  32  is not activated on a regular basis within a predetermined period of time (step  223 ), it assumes a malfunction to be present in the display driver  12 .  
         [0044]     In this case, the recovery component  22  causes a hardware reset of the display driver  12  by sending an interrupt to the display driver  12  via HW reset line  33  (step  224 ). As a result of the subsequent hardware reset, any recoverable malfunction is removed.  
         [0045]     Thus, a regular software refresh by way of precaution is not required anymore. This allows saving battery power in the mobile terminal  1 . Nevertheless, a malfunction is recovered immediately and comprehensively in an automatic manner whenever required.  
         [0046]     In the presented embodiment of a mobile terminal, a signal line  32  as such is present anyhow for conventional synchronization purposes. It is simply used in addition in accordance with the invention for the purpose of enabling a recovery of an LCD module from a malfunction. It is to be understood that if an electronic device does not comprise a signal line for synchronization purposes, such a signal line may be provided specifically for the purpose of enabling a recovery of a display module from a malfunction in accordance with the invention.  
         [0047]     While there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices and methods described may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.