Abstract:
Whenever an electrostatic discharge (ESD) event has occurred which may have corrupted the display registers, displays in a mobile telephone are reinitialized. A General Purpose Input/Output (GPIO) device is employed to trigger an interrupt whenever an antenna/detector, connected between the GPIO and a test point proximate the displays, detects the occurrence of an ESD event. The displays may then be checked for corruption and reinitialization of the displays may be performed as necessary.

Description:
TECHNICAL FIELD 
       [0001]    The present invention is directed to mobile telephones, more particularly, to a reinitialization of a mobile telephone display after an ESD event. 
       BACKGROUND 
       [0002]    Mobile communication devices, such as cellular phones and the like, have become increasingly prevalent. These devices provide the convenience of a handheld communication device that is capable of increased functionality. The focus of the structural design of mobile phones continues to stress compactness of size, incorporating powerful processing functionality within smaller and slimmer phones. To further these objectives, various devices have been developed and gained popularity, such as the flip phone, clam shell, slider, jack knife. Components of these devices are distributed within a housing of the phone body and a cover, which are movably coupled to each other. The cover may be in hinged or in slidable engagement with the housing. 
         [0003]    Structure of a typical flip, or clam-shell, phone is illustrated in perspective view in  FIG. 1 . The phone body  100  includes various keypad elements  108 , and a microphone (unlabeled), which are located at a surface of the body housing. Additional user control elements, not shown, may be provided at side surfaces of the housing. Within the housing are contained a controller and associated communication hardware, which are situated in one or more circuit boards. The phone body  100  is structurally coupled via hinge (unlabeled) to the cover, or upper portion,  102 . At the illustrated surface of cover  102  are a speaker (unlabeled) and displays  106 . The cover also includes other elements that are not shown, including an antenna. 
         [0004]    The main circuit board and the display are connected via a relatively long flex circuit extending between the two halves of the telephone. Electrostatic Discharges (ESD) near the display may cause the display to reset due to the impedance of the flex circuit. ESD is a common phenomenon and may occur, for example, as a static electricity charge when a user of a mobile telephone walks across a carpeted floor. An ESD may develop a voltage from +/−6 kV to +/−15 kV, or even larger. ESD near the display may cause the display to reset. An ESD voltage in the vicinity of 8,000 volts or more may corrupt the configuration registers of the display and thus the display. 
         [0005]    Conventionally, the display registers are continuously polled to check display status to determine whether they have been reset. If a reset has occurred, the display must be reset. However, in mobile telephone devices having a plurality of displays, such continuous polling is not efficient. Accordingly, a need exists for an improved ESD detection and reinitialization technique. 
       SUMMARY OF THE DISCLOSURE 
       [0006]    A clam-shell type mobile telephone, such as a flip phone or a slider type phone, is provided with a General Purpose Input/Output (GPIO) device, preferably, but not necessarily, located in a lower portion of the clam-shell type mobile telephone, and configured as an input to a long track, or antenna, that terminates, preferably, at the end of a flex circuit in an upper portion of the clam-shell type mobile telephone. This long track, or signal track, acts as an antenna and an ESD detector. 
         [0007]    In a preferred embodiment, the GPIO is located in the lower portion of the telephone and on a controller within the processing area of the telephone. The GPIO has a plurality of input pins to provide ease of connection to input and output signals. In particular, the GPIO is positioned on the Baseboard (BB) controller as an input with interrupt when an input pin state change occurs. The GPIO is connected to a voltage divider that acts as a trigger for the interrupt and may, for example, take the form of an RC-network, an RL-network, or a resistive network, that acts to reduce a large transient voltage in the form of an ESD to a more manageable level. 
         [0008]    The signal track, acting as an antenna, is connected between the voltage divider as an input to the GPIO, through the connecting flex, to a location where the display, or displays, are located. The track traverses the upper flex/PCB area and is terminated at an embedded test point. The location of the embedded test point is chosen to be at any appropriate location, preferably proximate the display, or displays, and on the distal end of the displays relative to the voltage divider, or trigger network, where an ESD event is likely to occur. Then, ESD events near the display, or displays, cause large transients on the ground plane that couples into the ESD detector track which, in turn, cause the interrupt to trigger on the appropriate GPIO input pin. When such a triggering occurs, the displays can then be checked, or polled, in any well known manner, as by appropriate software, and any displays that may have been reset by the ESD event can then be reinitialized. Reinitialization of the displays may be achieved by powering up the original initialization string applied to the display registers. 
         [0009]    In one preferred embodiment, the displays or, more properly, the registers of the displays, are reinitialized whenever an ESD event is detected, regardless of whether any displays were rest by the ESD event. 
         [0010]    In another embodiment, in response to the detection of an ESD event, the displays are checked to determine if the ESD event, in fact, has reset at least one of the displays. In this case, the displays are reinitialized only if they had been reset by the ESD event. Not every ESD event will result in the resetting of the displays and in those cases where an ESD event does not result in the resetting of the displays, it is not necessary to automatically reinitialize the display registers. 
         [0011]    Additional advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein only the preferred embodiment of the invention is shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a clam-shell type mobile telephone having a plurality of displays. 
           [0013]      FIG. 2  is a block diagram illustration of the connection between various elements of the mobile telephone. 
           [0014]      FIG. 3  is a more detailed circuit diagram of the mobile telephone configured in accordance with the present disclosure, illustrating the manner of connecting the signal track/antenna. 
           [0015]      FIG. 4  is an illustration of the specific connection between the test point, the trigger network and the GPIO. 
           [0016]      FIG. 5  is an illustration of several trigger networks that may be employed to connect between the signal track/antenna and the GPIO. 
           [0017]      FIG. 6  is an illustration of several trigger networks that may be employed to connect between the signal track/antenna and the GPIO when a double trigger is used as interrupts. 
           [0018]      FIG. 7  is a flowchart illustrating an embodiment for controlling the mobile telephone. 
           [0019]      FIG. 8  is a flowchart illustrating another embodiment for controlling the mobile telephone. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    With reference to  FIG. 1 , a flip-type, or clam-shell, mobile telephone  100  is shown. The telephone has an upper portion  102  and a lower portion  104 . In the upper portion  102  is depicted, for illustrative purposes only, two displays  106 . However, it should be recognized that there may be only a single display or there may be more than two displays. The lower portion  104  houses, in addition to a keypad  108 , the major components of the circuitry necessary to operate the mobile telephone  100 , much of which is familiar to skilled artisans and therefore is not specifically shown in the drawings. More detail of the components is shown in  FIG. 2 . 
         [0021]      FIG. 2  is an illustration of the connection between various elements of a mobile telephone  100 . In the upper portion  102 , as previously discussed, is at least one display  106 , in additional to components familiar to those skilled in the art, such as a speaker  215 . In accordance with the present disclosure, the upper portion  102  also contains an embedded test point  223 . In the lower portion  104  are conventional mobile telephone components, such as processor  205 , keyboard  108 , memory  209 , microphone  211 , and audio interface  213 , as well as components in accordance with the present disclosure, such as GPIO  219 , and voltage divider  221 . 
         [0022]    The GPIO  219  is configured as an input with interrupt on a pin state change. GPIO  219  is also connected to a voltage divider trigger  221 , shown in more detail in  FIGS. 5 and 6 , described below. The voltage divider  221  is external to the GPIO  219  and acts to adjust the signal level of any detected ESD and to trigger an interrupt. Since ESD events can result in extremely high voltage, and could easily destroy the delicate circuitry of a mobile telephone, the voltage divider network  221  acts to limit such high transient voltages to a more moderate level acceptable for processing by circuitry of the mobile telephone  100 . 
         [0023]    A signal track  225 , acting as an antenna and ESD detector, is connected from the voltage divider network  221  as an input to GPIO  219 , via the connecting flex (not shown) between the upper portion  102  and the lower portion  104  of mobile telephone  100 . The signal track  225  terminates at an embedded test point  223  within the upper portion  102 . The signal track  225  is preferably constructed of 3 mil copper trace routed through the flex circuit to the upper portion  102  of mobile telephone  100  to the distal end of the displays  106 , relative to the lower portion  104 . There is no restriction on the routing of the trace comprising the signal track/antenna and it can be routed in any convenient manner through the flex circuit. It is important, however, that the signal track/antenna trace does not connect to any electrical circuits other than GPIO  219  through voltage divider network/trigger network  221 . The test point  223  is preferably located in the upper portion  102  of mobile telephone  100  and, more preferably, at a location proximate to the displays  106  and on the distal end of the displays relative to the voltage divider, or trigger network  221 , so that an ESD event most likely to affect the displays  106  can more likely be detected. The voltage divider network  221  is connected to ground at  229 . Although shown separately from processor  205 , GPIO  219  may be a part of processor  205 , or GPIO  219  may have its own processing unit. 
         [0024]    When an ESD event occurs near the displays  106 , e.g., at the embedded test point  223 , the ESD event causes large transients on the ground plane and the transient signals are coupled into the signal track  225  causing the interrupt to trigger on an GPIO input pin. At this point, a check, or a poll, may be made of the displays  106  by processor  205  via line  227  in order to determine whether any or all of the displays  106  were reset by the ESD event. While this checking procedure may be performed by hardware, e.g., by logic circuits, etc., it is preferably performed by a software implementation. This software implementation is illustrated in  FIG. 7 . Processor  205  is connected to both the GPIO  219  (in the lower portion  104 ) and the displays  106  (in the upper portion  102 ) of the mobile telephone  100 . The processor  205  receives the interrupt information from GPIO  219  and the processor polls displays  106  to determine if any displays have been reset by the ESD event. The processor  205  may then send a signal to reinitialize the registers of displays  106  in that event. Alternatively, the processor  205  could send a signal to reinitialize the registers of displays  106  without polling the registers, i.e., it would reinitialize the display registers automatically upon detection of an ESD event. 
         [0025]      FIG. 3  illustrates a mobile telephone  100  and the connections therein in more detail. 
         [0026]    In the upper portion  102  of the mobile telephone, the plurality of displays  106  is shown as 24-pin LCD displays, with a main display  303 , a square display  305 , and a round display  307 . The test point  223  is shown at the upper end of the upper portion  102  further, rather than nearer, the lower portion  104 . The various electronic components of the mobile telephone  100  are depicted in detail in  FIG. 3 , clearly illustrating the relationship between the components on the main printed circuit board  308 , where GPIO  219 , which may take the form of a processor, is located in the lower portion  104 , and the display components  303 ,  305 , and  307 , external buttons  309 , and test point  223  are located in the upper portion  102 . The GPIO  219 , in the lower portion  104 , is connected to the test point  223 , in the upper portion  102 , by the signal track/ESD antenna  225 . The signal track/ESD antenna  225  is routed via a flex circuit  301  in no particular manner. 
         [0027]    The signal track/ESD antenna  225  is not directly connected to GPIO  219 , but, rather, to a triggering network, voltage divider  221  (not shown in  FIG. 3 ). This is depicted in more detail in  FIG. 4 . 
         [0028]      FIG. 4  depicts the connection between the embedded test point  223  and GPIO  219 , depicted in  FIG. 4  as GPIO inputs  401 ,  403 . A signal track/ESD antenna  225  is connected from test point  223  to trigger network  221 . An ESD event may generate a voltage from +/−6 kV to +/−15 kV, or even larger, and travels from the test point  223  along antenna  225  to the trigger network  221 . The trigger network  221  is external to the GPIO  219  and may employ one or two GPIOs  401 ,  403 . The GPIOs  401 ,  403  may be configured as inputs  401 ,  403  on a processor  205  with no internal pull resistor being active. ESD energy from an ESD event is capacitively coupled to the floating ESD antenna  225 , causing the GPIO, or GPIOs, to change state. Moreover, the GPIOs may be configured as a high impedance input and as an interrupt on logic transition (i.e., edge-triggered). When an interrupt is detected, software within the system will either determine if the LCD display registers are corrupted by reading each LCD display to determine if the configuration registers are corrupt, and then reinitialize the display, or simply reinitialize all LCD displays when an ESD event is detected. 
         [0029]    As depicted in  FIG. 5 , a single trigger network, e.g.,  221  described above, may take many forms, including an RC network in  FIG. 5(   a ), an LC network in  FIG. 5(   b ), or a resistive network in  FIGS. 5  ( c ) and ( d ). 
         [0030]      FIG. 6  illustrates examples of trigger networks, e.g.,  221  described above, when two GPIO triggers are employed, with  FIG. 6(   a ) depicting an RC network and  FIG. 6(   b ) depicting a resistive network. 
         [0031]    As depicted in  FIG. 7 , illustrating a method  700 , the process begins with powering-up the mobile telephone at block  701 . Then, a determination is made, at decision block  703  as to whether an ESD event has occurred. This determination comprises determining as to whether a transient voltage exceeds a predetermined magnitude. If an ESD event has not occurred, then the process returns to decision block  703 , awaiting an ESD event. If an ESD event has occurred (detected, for example, by signal track/antenna/detector  116 ), then an interrupt is triggered on a GPIO input pin at block  707  and a determination is made, at decision block  709 , as to whether a display has been reset as a result of the ESD event. If no display has been reset, then it is assumed that no harm has been done by the ESD event and the process returns to decision block  703  to await an ESD event. If a display has been reset by the ESD event, then the process continues to block  711  where the display registers are reinitialized by resetting the display registers with the original parameters set for display operation, e.g., by powering up the initializing string of parameters. The process then returns to decision block  703  to await a new ESD event. 
         [0032]      FIG. 8  illustrates a flowchart indicative of another embodiment for controlling the mobile telephone  100 . This embodiment is similar to the one depicted in  FIG. 7  except that no determination is made as to whether a display has been reset. Rather, the mobile telephone is powered-on at block  801 . A determination is then made at block  803  as to whether an ESD event has occurred. If not, the process returns to block  803  waiting for an ESD event to occur. If an ESD event has occurred, the process moves on to block  807  where an interrupt is triggered. Display registers are then reinitialized at block  811  and the process returns to block  803  to await another ESD event. Thus, in this embodiment, an interrupt is triggered and display registers are reinitiated each and every time an ESD event has been detected, regardless of whether a display has been reset by the ESD event. That is, every time an ESD event is detected the display registers would be automatically reinitialized. 
         [0033]    In the preceding specification, various preferred embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and the drawings are accordingly to be regarded in an illustrative rather than restrictive sense.