Abstract:
A computer motherboard detects the form factor type of the chassis in which it is installed to permit tailoring functionality accordingly.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to a computer motherboard detecting the form factor type of the chassis in which it is installed to permit tailoring functionality accordingly. 
   BACKGROUND OF THE INVENTION 
   In the PC world, it is common for one motherboard assembly to be used in multiple mechanical form factors. For instance, a single motherboard could fit in both a tower and a desktop enclosure. However, the different form factors might have different thermal profiles with different optimal fan speed curves. In addition, one form factor might expose different motherboard I/O than another. Other parameters likewise might vary with form factor. 
   Simply programming the motherboard&#39;s non-volatile memory to account for the form factor in which the motherboard is to be used is less than desirable. First, it locks the motherboard to the form factor that is programmed in memory until and unless the memory is reprogrammed, typically not a chore that end users would welcome. Also, it means that the memory must be programmed correctly, and moreover the location of the form factor type in memory can be accidentally or maliciously erased. Moreover, a replacement motherboard must be updated manually. 
   SUMMARY OF THE INVENTION 
   Accordingly, a motherboard (e.g., the basic input-output system (BIOS) of the motherboard) reads the form factor type directly from the chassis in which the motherboard is installed. Among various ways this may be accomplished is by using an elevated chassis mechanical feature or features that contact one or more individual conductive pads or plated-thru holes arrayed on the bottom of the motherboard. These pads/holes are electrically connected through resistors to a DC supply, and are connected to individual general-purpose input ports (GPIOs). The elevated feature or features can conduct one or more pad/holes to chassis ground, and collectively encode a unique chassis type that can be read by BIOS or other system software through the GPIOs. As an alternative to an electro-mechanical detection, electro-optical detection may be used, in which structural features on the chassis interact with light sensors on the motherboard to collectively encode the unique chassis type. 
   The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram of one non-limiting implementation in accordance with present principles, illustrating electro-mechanical chassis form factor detection; 
       FIG. 2  is a block diagram of another non-limiting implementation in accordance with present principles, illustrating electro-optical chassis form factor detection; 
       FIG. 3  is a schematic plan view of a first non-limiting embodiment showing contact pads on the motherboard; 
       FIG. 4  is a schematic plan view of the first embodiment showing a spring clip on one type of chassis form factor mating with a first one of the contact pads on the motherboard; 
       FIG. 5  is a schematic plan view of the first embodiment showing a spring clip on a second type of chassis form factor mating with a second one of the contact pads on the motherboard; 
       FIGS. 6 and 7  show alternate non-limiting embodiments of spring clips; 
       FIG. 8  is a schematic plan view of a second non-limiting embodiment showing plated through holes on the motherboard; 
       FIG. 9  is a schematic plan view of the second embodiment showing a frustum-like protrusion (colloquially, “ant hill”) on one type of chassis form factor mating with a first one of the through holes on the motherboard; 
       FIG. 10  is a schematic plan view of the second embodiment showing a frustum-like protrusion on a second type of chassis form factor mating with a second one of the through holes on the motherboard; 
       FIG. 11  shows elevational and plan views of one of the chassis protrusions of  FIGS. 9 and 10 ; 
       FIG. 12  is an elevational view illustrating the chassis protrusion extending into a motherboard through hole; 
       FIG. 13  is a schematic plan view of a third non-limiting embodiment showing pads on the motherboard that are offset from each other in both flat dimensions of the motherboard; 
       FIG. 14  is a schematic plan view of the third embodiment showing an oblong extension to the motherboard-chassis screw mount mating with a first one of the pads on the motherboard; 
       FIG. 15  is a schematic plan view of the third embodiment showing an oblong extension to the motherboard-chassis screw mount mating with a second one of the pads on the motherboard; 
       FIG. 16  shows elevational and plan views of one of the extensions of  FIGS. 14 and 15 ; and 
       FIG. 17  is a flow chart showing a method that can be used with the structures shown herein. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring initially to  FIG. 1 , a system is shown, generally designated  10 , which includes a flat typically rectilinear computer motherboard  12  and a hollow typically parallelepiped-shaped computer chassis  14  in which the motherboard  12  may be mounted. The motherboard  12  may bear one or more central processing units (CPU)  16  that can access one or more computable-readable media such as but not limited to a non-volatile memory (NVM)  18  to execute present principles. The NVM  18  may store chassis information as well as instructions such as a BIOS that can be executed by the CPU  16 . 
   In the non-limiting embodiment shown in  FIG. 1 , the motherboard  12  also bears one or more electro-mechanical sensor elements  20  that can communicate with a CPU bus  22 . One or more of the elements  20  mate with one or more structures  24  on the chassis  14 , with each form factor chassis type being equipped with form factor-unique structures  24 . That is, the number and/or chassis locations of the structure(s)  24  are unique to the form factor type of the chassis. This mating or interaction causes signals to be sent to the CPU  16  that indicate the type of chassis form factor with which the motherboard  12  has been engaged. In response, the CPU  16  executing, e.g., BIOS on the NVM  18  can establish a parameter, e.g., the speed of a cooling fan  26  on the chassis  14 , as appropriate for the form factor type in which the motherboard  12  finds itself. Various implementations of the sensor elements  20  are discussed further below. 
     FIG. 2  shows a system  10   a  that in all essential respects is identical to the system  10  shown in  FIG. 1 , except that instead of electro-mechanical sensor elements, the system  10   a  employs electro-optical sensor elements  28  on a motherboard  30  that interact with one or more form factor-unique structure  32  on a computer chassis  34 . The elements  28  may be pairs of light emitters (such as but not limited light emitting diodes (LED)) and light detectors (such as but not limited to photoresistors or phototransistors). The emitters emit light onto the structures  32  that may be, without limitation, holes or voids. It will readily be appreciated that the light reflected from the chassis is sensed by the detectors, with the structures  32  being arranged to ensure that the sensor elements  28  sense in combination a reflection pattern that is unique to the form factor of the chassis. The signals from the sensor elements  28  are used in accordance with principles discussed below in the case of signals from electro-mechanical sensor elements. 
     FIG. 17  shows non-limiting logic in accordance with present principles. At block  36  a motherboard is engaged with a chassis and at block  38  the form factor-unique chassis structure is detected by means of the sensor elements on the motherboard interacting with the form factor-unique chassis structure. The sensor elements provide a signal, functionally a form factor identification, to the motherboard CPU, which may, e.g., execute BIOS to look up or otherwise correlate the signal to one or more parameters at block  40 . The parameter(s) are established at block  42 , typically by the CPU. Non-limiting examples of parameters that are established include chassis fan speed, and activation or use of a particular type of input/output structure and/or protocol. 
     FIG. 3  shows an example non-limiting implementation in which electro-mechanical sensor elements on the motherboard  12  are established by electrically conductive contact pads  44  that can be aligned with each other in one flat dimension of the motherboard (looking down on  FIG. 3 , the Y-dimension) as shown and offset from each other in the other flat dimension (looking down on  FIG. 3 , the X-dimension). Each pad  44  is connected to a voltage source  46  through a respective resistor  48 . Also, each pad  44  is connected to a respective GPIO port  50  of an I/O port assembly  52 . The I/O port assembly  52  is connected to the system bus  22  shown in  FIG. 1  and, thus, to the CPU  16 . One or more screws  53  can engage the motherboard with the chassis. 
     FIGS. 4 and 5  show that the structure of the chassis that engages the sensor elements of the motherboard may be one or more electrically conductive spring clips  54  that wipe against one of the pads. In  FIG. 4 , the spring clip  54  is on one type of chassis form factor and abuts against the upper contact pad  44  on the motherboard when the motherboard is engaged with the chassis. In contrast, in  FIG. 5  a spring clip  54   a  is arranged on a second type of chassis form factor to mate with the lower contact pad  44  on the motherboard. In one implementation, when a spring clip abuts a contact pad the contact pad is grounded, and otherwise it is not. In this way, the signals generated through the contact pads  44  and sent to the CPU  16  depend on which pad or pads are engaged by spring clips to in effect encode the signal uniquely for the form factor type of the chassis. 
     FIG. 6  shows that a spring clip  56  can be connected to the chassis by a mounting screw  58 . In another embodiment shown in  FIG. 7 , a spring clip  60  is formed integrally with a substrate  62  of the chassis by, e.g., cutting material away from three sides of a rectangular opening in the substrate and leaving the fourth side uncut. 
     FIGS. 8-12  show another implementation of the electro-mechanical sensor elements, this time established by electroplated through holes  70  in the motherboard that mate with an electrically conductive frusto-conical protrusion  72  (colloquially, “ant hill”) on the chassis. In  FIG. 9 , a protrusion  72  on a first type of form factor protrudes partially through the upper hole  70 , grounding it, while in  FIG. 10  a protrusion  74  on a second type of form factor protrudes partially through the lower hole  70 , grounding it. The frusto-conical shape of the ant hill  72  is shown in  FIG. 11 , and in  FIG. 12  the upper part of the protrusion  72  is shown extending through the hole  70  such that the sides of the protrusion  72  abut the plated sides of the hole  70 . 
     FIGS. 13-16  show yet another implementation of the electro-mechanical sensor elements, this time established by pads  80  on the motherboard that are offset from each other in both flat dimensions of the motherboard, one of which mates with an electrically conductive non-round extension  82  that may be oriented as appropriate for the form factor type of the chassis by engaging the mounting screw  84  with the extension. In the embodiment shown, the extension may be oblong or ovular or elliptical or otherwise not circular, so that depending on its orientation it can contact only one of the pads  80  at a time. In  FIG. 14  the extension  82  is oriented to contact the upper right pad  80  to indicate a first type of form factor whereas in  FIG. 15  the extension  82  is oriented to contact the lower left pad  80  to indicate a second type of form factor.  FIG. 16  shows two views of the extension  82 . 
   It may now be appreciated that for each chassis form factor, the location and/or orientation of the chassis structures are fixed relative to the pad/hole array of the motherboard. Only those elevated features required to encode the chassis type for that particular chassis are required to be implemented. The feature(s) could be implemented with a spring clip, ant-hill, or oblong extension to an existing mounting hole ant-hill. Spring clips can mate with motherboard pads, while ant-hill or ant-hill extensions can mate with motherboard plated-thru holes. The ant-hill or extension can rise to an elevation just above the bottom surface of the mounted motherboard, such that the top of the hill can make contact by pressing against the inner diameter of the plated-thru hole. The chassis form factor type may be encoded in binary across multiple elevated features, or each chassis type can claim one unique feature. Using the spring clip method, a single common spring clip can be used across multiple chassis types, with each chassis locating the spring clip to match a different pad in the array. 
   While the particular MOTHERBOARD DETECTION OF COMPUTER CHASSIS TYPE is herein shown and described in detail, it is to be understood that the subject matter which is encompassed by the present invention is limited only by the claims.