Abstract:
Systems and methods for testing a peripheral in accordance with a high-speed serial interface protocol are provided. A test system can test a peripheral by providing user-specified control over a test processor (which is substantially the same processor the peripheral will interface with when installed) to test, calibrate, or both test and calibrate the peripheral. The test processor can communicate with the peripheral according to the high-speed serial interface protocol, thereby effectively providing an actual “in-device” environment for testing and/or calibrating the peripheral.

Description:
This application claims the benefit of U.S. provisional patent application 61/069,398, filed Mar. 14, 2008, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to testing systems, and in particular to testing systems that test peripherals that interface with a processor using a particular communications protocol. 
     Processors or systems-on-a-chip (SOC) are ubiquitous in electronic devices and often serve as the central hub of data exchange between the processor and peripherals such as memory, cameras, displays, or communications devices. The SOC may include several ports or buses for interfacing with the peripherals. This enables more efficient integration of peripherals, resulting in electronic devices such as laptops, phones, PDAs (personal digital assistants), personal media players, etc., that offer more features and power savings than before. 
     Such integration may require that the peripherals be tested, tuned, or calibrated in order to provide an electronic device that meets minimum performance criteria. Peripherals may need to be tested and/or calibrated because each peripheral may be unique and thus may have slightly different operating characteristics. For example, liquid crystal displays (LCDs) of the same make and model can be unique and differ from one another. Thus, merely interfacing any LCD with the SOC of an electronic device and operating each LCD according to the same fixed set of parameters may not yield desired performance. 
     Testing and/or calibrating peripherals after they have been installed into the electronic device are not practical, and in many situations are not possible. This may be due to the closed nature of the integrated SOC/peripheral solution and the specific communications protocols used to conduct communications between the SOC and the peripheral. One protocol, known as a mobile industry processor interface (MIPI) advantageously enables a processor to substantially directly communicate with a peripheral, thereby further enabling tighter system integration, but also making it more difficult or practically impossible to test and/or calibrate the peripheral after it is installed in the device. 
     Accordingly, what is needed is a test system to test a peripheral in accordance with a MIPI protocol. 
     SUMMARY 
     Systems and methods for testing a peripheral in accordance with a MIPI protocol are provided. A test system can test a peripheral by providing user-specified control over a test processor (which is substantially the same processor the peripheral will interface with when installed) to test, calibrate, or both test and calibrate the peripheral. The test processor can communicate with the peripheral according to the MIPI protocol, thereby effectively providing an actual “in-device” environment for testing and/or calibrating the peripheral. 
     In one embodiment, a test system can include a test computer and a testing module. The testing module may serve as an interface between a peripheral (e.g., an LCD subassembly or camera) and the test computer and includes a test processor. The test processor may be the same make and model as the processor the peripheral will interface with when it is installed into an end product (e.g., an electronic device). A difference with the test processor is that it is “opened up” and permits the test computer to run tests or calibration events on the peripheral through the processor, which uses the MIPI protocol to communicate with the peripheral. 
     In another embodiment, the test system may be used to test and adjust various settings of an LCD attached to the testing module. For example, the test system may adjust the flicker and gamma parameters of the LCD to obtain optimal LCD performance. After those parameters are determined, the test system may program an LCD driver with those determined parameters, for example, by writing those parameters to memory in the LCD driver. 
     In yet another embodiment, an electronic device is provided that includes a peripheral (e.g., LCD) that was tested and calibrated by a MIPI test system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects and advantages of the invention will become more apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which: 
         FIG. 1  is an illustrative block diagram of an end-use system including a peripheral that was tested and calibrated by a testing platform in accordance with an embodiment of the invention. 
         FIG. 2  shows an illustrative test system according to an embodiment of the invention. 
         FIG. 3  is a flow chart of illustrative steps that may be performed by a test system in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is an illustrative block diagram of a system  100  including an LCD  110  that was tested and calibrated by a testing platform (e.g., as shown in a later FIG.) in accordance with an embodiment of the invention. As shown, LCD  110  may have LCD driver  112  mounted thereon. LCD driver  112  may be connected to connector  114  via a flex (connection outlined by the dotted lines between elements  112  and  114 ). The combination of LCD  110 , driver  112 , and connector  114  may be a subassembly (denoted by dashed box  116 ) that is tested by a testing platform according to the invention prior to assembly of system  100 . 
     Connector  114  may be electrically coupled to processor  120  via communications paths  118 . Communications paths  118  may be any suitable path for transmitting data signals. For example, communications paths  118  may be a wired link or a fiber optic link. 
     Processor or CPU  120  may transmit and/or receive data according to a particular protocol. In one embodiment, the protocol may be a MIPI protocol, which is a differential-ended, high-speed, serial interface (HSSI) used to interface processor  120  and LCD  110 . Structurally, MIPI uses a pair of wires for each lane being used to transmit data. For example, in one embodiment, a clock lane and at least one data lane may be used to transmit information to LCD  110 . The data may be transmitted in packets. For example, a packet may include header information and data. The header information may specify if the data is control information (which may be used to control, for example, workflow) or image information (which may be used to generate red/green/blue values for pixels in the display). Advantages of using MIPI include reduced number of wires, faster charge/discharge of parasitic capacitance, reduced voltage swing, reduced number of pins, and increased signal integrity. To achieve optimal performance, various portions of the peripheral interfacing with the processor using MIPI (e.g., LCD driver  112 ) may require customization. These customized parts may require custom programming, which is provided using a testing system in accordance with embodiments of this invention. 
     As also shown in  FIG. 1 , system  100  can include volatile memory  130  (e.g., ram or DDR) and non-volatile memory  140  (e.g., flash or a hard-disk). Processor  120  can communicate with memories  130  and  140  to obtain data as needed and provide it, for example, to a peripheral. For example, when system  100  displays content on LCD  110 , processor  120  may obtain content from non-volatile memory  140 , buffer a frame of content in volatile memory  130 , and provide the buffered content to LCD  110  over path  118 , according to the MIPI protocol, for display. 
     Using the MIPI protocol, processor  120  can substantially directly communicate with LCD driver  112 . That is, there is no need for bridge circuitry, which is used in connection with MPL (i.e., single-ended HSSI) protocol systems, to be disposed between processor  120  and connector  114 . (MPL is the acronym for the Mobile Pixel Link communications protocol.) The MIPI protocol offers substantial advantages over its MPL counterpart in terms of performance and system integration. In terms of integration, processor  120  can process data retrieved from memory  130  or  140  according to the MIPI protocol and provide it to LCD  110 . Thus, because processor  120  is processing data according to the MIPI protocol, peripherals (such as LCD  110 ) interfacing with processor  120  may need to be tested and/or calibrated to ensure optimal operation. For example, it may be necessary to test whether a peripheral is properly receiving or processing data according to the MIPI protocol. In another example, a test may need to be run to determine if the peripheral is operating according to predetermined criteria. 
       FIG. 2  shows an illustrative test system  200  according to an embodiment of the invention. Test system  200  can include test computer  210 , test module  220 , and LCD subassembly  116 . Module  220  can include test processor  120 , dock  222 , dock  224 , interface  226 , and daughter-board  230 . Test processor  120  may be another instance of the same processor as that shown in  FIG. 1 . Using the same processor (i.e., processor  120 ) in test system  200  that is used in end-use system  100  advantageously promotes testing and calibration of LCD subassembly  116 . (The phrase “end-use” just refers to the final hook-ups or connections to peripheral  116  per se.) It will be understood that the term “same processor” refers to the same make and model processor, both instances of which may be operating according to the same firmware instruction set (stored, e.g., in memory  221 ). If it is desired to update the firmware or other software of test system  200 , test computer  210  may provide such updates via dock  224 . 
     Test computer  210  may be electrically coupled to test processor  120  via path  212  and dock  222 . Through path  212 , test computer  210  may control processor  120  to test a peripheral (shown as LCD subassembly  116 ) attached to module  220 . Commands and data provided by test computer  210  may be processed by processor  120  and provided to interface  226 , which routes the commands and data through daughter-board  230  to connector  114 . After test computer  210  finishes testing and/or calibrating subassembly  116 , subassembly  116  may be removed and a new one put in its place. 
     Test computer  210  may include software (e.g., a control application)  211  to control test module  220  and test a peripheral (shown as LCD subassembly  116 ) attached to test module  220 . The software  211  may test any number of parameters related to the peripheral  116  or the system (e.g., processor). For example, in an embodiment where the peripheral is an LCD subassembly, the test computer  210  may test display  110  for flicker and gamma performance, test the system for serial interface link performance, and test the system for optical performance. In addition, test computer  210  may be able to adjust various parameters affiliated with the peripheral. In the LCD subassembly  116  embodiment, adjustments may be made for flicker and gamma values. The adjustments may be made at the direction of a user who manually directs the adjustments though test computer  210 , or adjustments may be performed automatically by test computer  210 . Automatic adjustments may be performed, for example, by having a camera (not shown) monitor the LCD screen and feed back data (e.g., flicker and gamma values) to test computer  210 , which uses that data to make adjustments as necessary. 
     Test computer  210  may also be able to program peripherals attached to module  220 . For example, after test computer  210  determines the appropriate flicker and gamma values for subassembly  116 , test computer  210  may program an eeprom (not shown separately) located in LCD driver  112  so that it operates according to the flicker and gamma values determined to work best for this particular subassembly  116 . 
     One of the advantages of test system  200  is that it permits test computer  210  to directly access and control MIPI protocol commands in processor  120 . 
       FIG. 3  is a flow chart of illustrative steps that may be performed by a test system (e.g., as in  FIG. 2 ) in accordance with an embodiment of the invention. Starting at step  310 , a peripheral (e.g., an LCD subassembly  116 ) is connected to a testing system (e.g., daughter-board  230  of  FIG. 2 ). At step  320 , tests may be performed on the peripheral using a test processor (e.g.,  120 ) processing data and commands supplied by a test computer (e.g.,  120 ). If desired, tests may be performed to evaluate the communications link (e.g.,  112 ,  114 , etc.) between the test processor (e.g.,  120 ) and the peripheral (e.g.,  116 ). 
     At step  330 , at least one parameter associated with the peripheral (e.g.,  116 ) is adjusted to determine an optimal parameter setting for such parameter(s). It will be understood that steps  320  and  330  may be performed in conjunction with each other. The parameter adjustments may be performed by the test processor (e.g.,  120 ) under the direction of the test computer (e.g.,  210 ). After all adjustable parameters have been found, the optimal parameter settings(s) may be saved on the peripheral (e.g.,  116 ), as indicated by step  340 . The test processor (e.g.,  120 ) may save the settings in on-board memory mounted to the peripheral (e.g.,  116 ). 
     It will be appreciated that these steps are merely illustrative, and that additional steps may be included or existing steps may be omitted. For example, a step may be added to account for manual input of parameter adjustments by a test system user. 
     The foregoing describes systems and methods for testing peripherals that interface with a processor using a MIPI protocol. Those skilled in the art will appreciate that the invention can be practiced by other than the described embodiments, which are presented for the purpose of illustration rather than of limitation, and the invention is limited only by the claims which follow.