PATENT DOCUMENT

Publication Number: US-9157953-B2
Application Number: US-201113107416-A
Country: US
Kind Code: B2

Title: Test systems with cables that support multiple communications buses

Abstract:
A test system may include test stations for testing a device under test. The test stations may each include test equipment that may be connected to a device under test using a test cable. The test cable may include a status indicator to indicate when tests have been passed or have failed. A first connector at one end of the test cable may be coupled to the test equipment. A second connector at an opposing end of the test cable may be coupled to the device under test. Communications through the first connector may use a first communications protocol. Communications through a first set of contacts in the second connector may use the first communications protocol. Communications through a second set of contacts in the second connector may use a second communications protocol.

Claims:
What is claimed is:  
     
       1. A method for performing tests using a test system having test equipment that is coupled to devices under test by a cable, comprising:
 at a test station in the test system, transferring data between test equipment and the device under test through the cable using both a first communications protocol and a second communications protocol during manufacture of the devices under test, wherein the cable comprises a wired path having first and second connectors at opposing ends of the wired path; 
 transferring software from the test equipment to the devices under test using the first communications protocol and a first set of contacts in the second connector; and 
 transferring test commands from the test equipment to the devices under test using the second communications protocol and a second set of contacts in the second connector that is different from the first set of contacts so that multiple types of test operations are performable at a single test station. 
 
     
     
       2. The method defined in  claim 1  wherein the first communications protocol comprises a Universal Serial Bus protocol and wherein transferring the data comprises transferring data between the test equipment and the device under test using the Universal Serial Bus protocol. 
     
     
       3. The method defined in  claim 2  wherein the second communications protocol comprises a Universal Asynchronous Receiver-Transmitter protocol and wherein transferring the data comprises transferring the data between the test equipment and the device under test using the Universal Asynchronous Receiver-Transmitter protocol. 
     
     
       4. The method defined in  claim 3  wherein the cable comprises a wired path, first and second connectors at opposing ends of the wired path, and control circuitry interposed within the wired path, wherein the first connector is configured to be connected to the test equipment, wherein the second connector is configured to be connected to the device under test, wherein the control circuitry includes a first Universal Serial Bus endpoint that supports communications with the test equipment through the first connector, wherein the control circuitry includes a second Universal Serial Bus endpoint that supports communications with the device under test through a first set of contacts in the second connector, and wherein the control circuitry includes a Universal-Serial-Bus-Universal-Asynchronous-Transmitter-Receiver converter that supports communications with the device under test through a second set of contacts in the second connector using the Universal Asynchronous Receiver-Transmitter protocol, the method further comprising:
 transferring a test program to the device under test from the test equipment at the test station using the first and second Universal Serial Bus endpoints. 
 
     
     
       5. The method defined in  claim 4  further comprising:
 transferring test commands to the device under test from the test equipment at the test station using the first Universal Serial Bus endpoint and the Universal-Serial-Bus-Universal-Asynchronous-Transmitter-Receiver converter. 
 
     
     
       6. A cable for use in connecting test equipment to a device under test in a test system, comprising:
 a first connector that is configured to connect to the test equipment; 
 a second connector that is configured to connect to the device under test; 
 a wired communications path between the first connector and the second connector; and 
 control circuitry interposed within the wired communications path, wherein the control circuitry includes a first Universal Serial Bus endpoint that supports communications with the test equipment through the first connector, wherein the control circuitry includes a second Universal Serial Bus endpoint that is configured to convey software between the test equipment and the device under test through a first set of contacts in the second connector, and wherein the control circuitry includes a Universal-Serial-Bus-Universal-Asynchronous-Transmitter-Receiver converter that is configured to convey test commands between the test equipment and the device under test through a second set of contacts in the second connector by converting between a Universal Serial Bus protocol and a Universal Asynchronous Transmitter Receiver protocol. 
 
     
     
       7. The cable defined in  claim 6  wherein the first connector comprises a Universal Serial Bus connector. 
     
     
       8. The cable defined in  claim 7  wherein the second connector comprises a 30-pin data connector. 
     
     
       9. The cable defined in  claim 8 , further comprising a status indicator coupled to the control circuitry. 
     
     
       10. The cable defined in  claim 9  wherein the status indicator comprises a plurality of light-emitting components that are selectively illuminated to provide a system operator with test status information during testing of the device under test by the test equipment. 
     
     
       11. The cable defined in  claim 6  further comprising:
 a status indicator coupled to the control circuitry. 
 
     
     
       12. The cable defined in  claim 11  wherein the status indicator comprises a plurality of light-emitting components that are illuminated to provide a system operator with test status information during testing of the device under test by the test equipment. 
     
     
       13. The cable defined in  claim 12  wherein the light-emitting components comprise at least two light-emitting diodes of different colors. 
     
     
       14. A method of testing a device under test that is coupled to test equipment at a test station by a cable that has first and second connectors, comprising:
 at the test station, loading software into the device under test from the test equipment through both the first and second connectors using Universal Serial Bus communications and conveying data between the device under test and the test equipment through both the first and second connectors using Universal Asynchronous Receiver Transmitter communications, wherein conveying the data comprises conveying test commands from the test equipment to the device under test using a first set of contacts in the second connector, and wherein loading the software comprises loading the software from the test equipment into the device under test using a second set of contacts in the second connector that is different than the first set of contacts so that loading of the software and conveying of the test commands are both performed over the cable without coupling additional cables to the test station. 
 
     
     
       15. The method defined in  claim 14  further comprising:
 illuminating status indicator lights on the cable in response to detection of a failed test while testing the device under test with the test equipment. 
 
     
     
       16. The method defined in  claim 15  wherein loading the software comprises loading an operating system. 
     
     
       17. The method defined in  claim 15  wherein loading the software comprises loading a test program into the device under test.

Description:
BACKGROUND 
     This relates to testing, and, more particularly, to testing electronic devices during manufacturing. 
     Electronic devices such as portable computers, media players, cellular telephones, set-top boxes, and other electronic equipment must generally be tested during manufacturing. During testing, an electronic device that is being tested is often referred to as a device under test. In a typical scenario, a device under test may be passed through multiple test stations. At each test station, the device under test may be coupled to a different set of test equipment. Different types of test stations may communicate with the device under test using different types of communications links. For example, some test stations may communicate with the device under test using a Universal Serial Bus (USB) path, whereas other test stations may communicate with the device under test using a Universal Asynchronous Receiver/Transmitter (UART) path. The use of different communications links such as these may make it difficult or impossible to perform more than one type of activity at the same test station and may lead to other inefficiencies. 
     It would therefore be desirable to be able to provide improved test systems for testing devices under test using multiple types of communications links. 
     SUMMARY 
     A test system may include test stations for testing a device under test. The test stations may each include test equipment that may be connected to a device under test using a test cable. The test cable may include a status indicator to indicate when tests have been passed or have failed. 
     A first connector at one end of the test cable may be coupled to the test equipment. A second connector at the opposing end of the test cable may be coupled to the device under test. Communications through the first connector may use a first communications protocol. Communications through a first set of contacts in the second connector may use the first communications protocol. Communications through a second set of contacts in the second connector may use a second communications protocol. 
     The first communications protocol may be, for example, a Universal Serial Bus (USB) communication protocol. The second communications protocol may be, for example, a Universal Asynchronous Receiver Transmitter (UART) protocol. 
     Software such as test programs and an operating system for the device under test may be loaded from the test equipment into the device under test through the first connector and the first set of contacts for the second connector using the first communications protocol. Corresponding test logs and other test results may be conveyed from the device under test to the test equipment through the same path. Test data such as test commands and test results may be conveyed between the test equipment and the device under test through the first connector and the second set of contacts using the second communications protocol. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an illustrative device under test of the type that may be tested using a test system in accordance with an embodiment of the present invention. 
         FIG. 2  is a diagram of illustrative test equipment for testing a device under test at a test station in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of an illustrative cable that may be used to couple a device under test to test equipment at a test station in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram of an illustrative test system of the type that may include multiple test stations in which devices under test are coupled to test equipment using cables of the type shown in  FIG. 3  in accordance with an embodiment of the present invention. 
         FIG. 5  is a flow chart of illustrative steps involved in testing electronic devices in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as cellular telephones, media players, computers, set-top boxes, and other electronic equipment may be tested and loaded with software during manufacturing. During these operations, electronic devices may be referred to as devices under test. Following testing, a device that has passed its tests may be shipped to a customer. 
     An illustrative electronic device of the type that may be tested during manufacturing is shown in  FIG. 1 . As shown in  FIG. 1 , device under test  10  may include storage and processing circuitry  12  and input-output devices  14 . Storage and processing circuitry  12  may include microprocessors, microcontrollers, digital signal processor integrated circuits, application-specific integrated circuits, and other processing circuitry. Volatile and non-volatile memory circuits such as random-access memory, read-only memory, hard disk drive storage, solid state drives, and other storage circuitry may also be included in storage and processing circuitry  12 . 
     Storage and processing circuitry  12  may use input-output devices  14  to obtain user input and to provide output to a user. Input-output devices  14  may include speakers, microphones, sensors, buttons, keyboards, displays, touch sensors, wireless circuitry such as wireless local area network transceiver circuitry and cellular telephone network transceiver circuitry, and other components for receiving input and supplying output. 
     Device under test  10  may include one or more input-output ports. For example, device under test  10  may include a connector such as connector  24  for forming a data input-output port. Connector  24  may have a number of contacts (sometimes referred to as pins). When a mating connector is plugged into connector  24 , contacts (pins) on the mating connector will make electrical connections with the contacts in connector  24 . Data may then be conveyed between device under test  10  and equipment that is electrically connected to the mating connector. In a normal (non-testing) environment, connector  24  may be used to couple the device to external equipment such as a computer or accessory (as examples). During testing, connector  24  may be used to handle test data (e.g., test commands and test results). Connector  24  may also be used in loading an operating system and other software. 
     Different sets of contacts in connector  24  may be associated with different communications buses and different associated communications protocols. For example, device under test may use a first communications circuit such as Universal Serial Bus (USB) communications circuit  16  (e.g., a USB endpoint) to handle USB communications through contacts  26  and may use a second communications circuit such as Universal Asynchronous Receiver Transmitter (UART) communications circuit  18  to handle UART communications through contacts  28 . Using USB communications protocols and USB circuit  16 , device under test  10  can communicate over a USB bus coupled to contacts  26 . Using UART communications protocols and UART circuit  18 , device under test  10  can communicate over a UART bus coupled to contacts  28 . 
     Different buses and protocols may be suitable for handling different types of communications traffic. For example, USB communications may be suitable for loading test software (test programs) onto device under test  10 , for conveying test logs and other such test results that are generated by the test programs from device under test  10  to external test equipment, and for loading an operating system or other code from test equipment to device under test  10  following successful test operations. UART communications may be suitable for transferring test commands from external test equipment to device structures under test  10 . For example, UART communications may be used to send a “baseband power up” command from external test equipment to a baseband processor integrated circuit or other wireless communications circuit in device under test  10 . As another example, test equipment may use UART communications to send a “video on” or “video off” test command to video circuitry in device under test  10  or may send commands to device under test  10  that that exercise audio circuitry in device under test  10 . UART communications may also be used by test equipment that is coupled to device under test  10  when the test equipment wants to query device under test  10  for test results. 
     Test equipment for testing device under test  10  of  FIG. 1  may be formed using one or more computers, dedicated test units that perform test functions, and other suitable computing and test equipment. Illustrative test equipment  30  for testing device under test  10  is shown in  FIG. 2 . In the example of  FIG. 2 , test equipment  30  includes a computer such as computer  42  that is coupled to a USB hub such as USB hub  32  by USB path  44 . USB hub  32  may, if desired, be integrated into computer  42 . 
     USB hub  32  may have multiple USB ports such as ports formed from USB connectors  34 . During testing, multiple devices under test may be plugged into hub  32  using connectors  34  to support parallel testing. As shown in  FIG. 2 , cables such as cable  36  may have a cable (wires)  40  that is terminated in connectors. The end of cable  36  that is connected to test equipment  30  may, for example, have a connector such as USB connector  38  that is configured to mate with USB connector  34  in USB hub  32 . 
     Cable  36  may have interface circuitry that converts USB traffic from test equipment  30  into USB and UART traffic for respectively communicating with USB circuit  16  and UART circuit  18  in  FIG. 1 . An illustrative configuration that may be used for cable  36  is shown in  FIG. 3 . As shown in  FIG. 3 , cable  36  may have a first end that is terminated with connector  38  and an opposing second end that is terminated with connector  44 . Connector  38  may be a USB connector having a housing such as housing  40  that is used to house USB connector structure  42 . Connector structure  42  may mate with a corresponding connector structure in connectors  34  of  FIG. 2 . Connector  44  may be a connector such as a 30-pin data connector. As shown in  FIG. 3 , connector  44  may have a connector housing such as housing  40  in which connector structure  48  (e.g., a 30-pin connector structure) is mounted. Connector structure  48  may be configured to mate with connector  24  of  FIG. 1 . When mated in this way, contacts (pins)  50  of connector  44  may mate with corresponding contacts  26  in connector  24  and contacts (pins)  52  of connector  44  may mate with corresponding contacts  28  in connector  24 . In general, connectors  38  and  44  may be implemented using any suitable types of connectors (e.g., USB, mini USB, Firewire®, 30-pin, Ethernet, audio connectors such as TRRS connectors, video connectors such as DVI, VGA, and HDMI connectors, or other types of signal connectors). The use of USB and 30-pin connectors in the example of  FIG. 2  is merely illustrative. 
     Connectors  44  and  38  may be coupled using cable paths  58 . Cable paths  58  may include wires (e.g., wires bundled to form cables or other wired paths). Data conversion circuitry  60  may be interposed in the wired path between connectors  44  and  38 . As shown in  FIG. 3 , at connector  44 , cable path  58  may include wires such as wires  54  that are connected to contacts  50  in connector structure  48  and may include wires such as wires  56  that are connected to contacts  52  in connector structure  48 . The portion of wired path  58  between connector  38  and circuitry  60  may include wires for coupling USB connector  38  to USB communications circuitry (USB endpoint)  68 . Wired path  54  may be coupled to USB communications circuitry (USB endpoint)  62 . Wired path  56  may be coupled to USB-UART converter  64 . 
     Control circuitry  70  may use USB communications circuitry  62 , USB-UART converter  64 , USB communications circuitry  68 , and USB hub and control logic  66  to create an interface between connector  38  and connector  44 . USB traffic that is supplied to connector  38  from test equipment ( FIG. 2 ) may contain data that is destined to the USB portion of connector  44  (i.e., contacts  50 ) and may contain data that is destined to the UART portion of connector  44  (i.e., contacts  52 ). Control circuitry  70  may route the traffic that is destined to the USB portion of connector  44  to USB communications circuit  62  through USB communications circuitry  68  and circuitry  66  for transmission to contacts  50 . Control circuitry  70  may route the traffic that is destined to the UART portion of connector  44  to USB-UART converter  64  through USB communications circuitry  68  and circuitry  66 . USB-UART converter  64  may convert the outgoing data to data using UART communications protocols suitable for communicating with UART circuitry  18  of  FIG. 1 . Control circuitry  70  may route USB traffic from USB circuit  16  of device structures under test  10  and contacts  52  to connector  38  using USB communications circuitry  62 , circuitry  66 , and USB communications circuitry  68 . Control circuitry  70  may route UART traffic from UART circuitry  18  to USB communications circuitry  68  via USB-UART converter  64  (which converts UART traffic into USB traffic) and circuitry  66 . Control circuitry  70  therefore serves as an interface between the single communications bus (i.e., the USB bus) that is associated with connector  38  and the two communications buses (i.e., the USB bus and the UART bus) that are respectively associated with the two sets of contacts ( 50  and  52 ) in connector  44 . 
     If desired, cable  36  may include status indicator  72  for providing test status information to an operator of the test system. Status indicator  72  may include a display, one or more light-emitting diodes  74 , lamps, audio components such as speakers or tone generators, or any other suitable components for generating visual and/or audible status output for an operator. In the example of  FIG. 3 , status indicator  72  includes three light-emitting components (e.g., light-emitting diodes) color-coded green, yellow, and red. If desired, other numbers of light-emitting components, light-emitting components with different colors, and other status indicator components may be used in status indicator  72 . The example of  FIG. 3  that uses red, green, and yellow lights is merely illustrative. 
       FIG. 4  is a diagram of an illustrative test system that may be used in testing device structures under test  10 . As shown in  FIG. 4 , test system  76  may contain multiple test stations TS 1  . . . TSK . . . TSN arranged along conveyor belt  88 . Initial test station TS 1  may include test equipment  30 - 1  with connectors  34 - 1  such as USB connectors. Intermediate test stations TSK may have test equipment  30 -K with USB connectors  34 -K. Final test station TSN may have test equipment  30 -N with USB connectors  34 -N. Equipment  30 - 1 ,  30 -K and  30 -N may be, for example, equipment such as equipment  30  of  FIG. 2 . 
     There may, in general, be any suitable number of test stations in system  76  (e.g., one or more, two or more, three or more, or four or more). Conveyor belts such a conveyor belt  88  moving in direction  90  or other structures may be used to assist test system operators in moving devices under test  10  between test stations in test system  76 . 
     Initially, a device under test may be placed on the left-hand end of conveyor belt  88  (as an example). An operator may remove the device under test and may test the device under test at the first test station (TS 1 ). Following successful operations at the first test station, the device under test may be transferred to subsequent test stations (e.g., one or more intermediate test stations TSK). If testing at the intermediate test stations is successful, testing and final manufacturing operations (e.g., installation of an operating system) may be performed at final test station TSN. If the device under test passes testing at final test station TSN, the device may be shipped to a customer (e.g., a store or an end user). 
     Each test station may, in general, be used to perform one or more different types of operation on device structures under test  10 . For example, test station TS 1  may be used in loading test software onto device under test  10  and may be used in performing an initial test or series of tests. Different tests may be performed at intermediate test stations TSK. Final test station TSN may be used to perform final tests and may be used to load the operating system onto device under test. 
     The different types of operations that are performed at the different test stations and that are performed at different times at the same test station may require use of different communications buses in cable  36 . For example, some operations (e.g., loading software such as a test program or an operating system) may be performed using USB communications. Other operations (e.g., sending test commands and gathering corresponding test results) may be performed using UART communications. When cables such as cable  36  are used to couple device under test  10  to test equipment  30 , there is no need to swap cables and reconfigure test equipment in the middle of testing. A single cable connection may be formed that may be left in place during all (or substantially all) test operations at that test station. Because both USB and UART communications can be handled over the same cable without need to adjust the connections between the cable, device under test, and test equipment, multiple operations may be performed at a single test station. For example, test program loading operations or operating system loading operations using the USB path in the cable may be performed at the same test station in which UART test commands and UART test results are conveyed between the device under test and the test equipment using the UART path in the cable. 
     During testing, status indicator  72  may be used to convey status information to an operator. For example, the yellow light-emitting component (Y) in status indicator  72  may flash or otherwise be illuminated during testing, the red light-emitting component (R) in status indicator  72  may be illuminated when a fault is detected in device under test  10 , and the green light-emitting component (G) in status indicator  72  may be illuminated when device under test  10  passes the tests at a particular test station. 
     As shown in  FIG. 4 , it is not necessary for each test station to use cables such as cable  36  of  FIG. 3 . For example, intermediate test stations TSK may use cable  78 . Cable  78  may have a converter such as converter  82  interposed between cable sections  86 . Cable  78  may have connector  80  coupled to device structures under test and connector  84  coupled to test equipment  30 -K. Converter  82  may convert USB traffic from connector  84  into UART traffic for connector  80  and vice versa (i.e., cable  78  may contain only a single USB-UART path, without including a path such as USB-USB path  54  of  FIG. 3 ). If desired, other cable branches may be coupled to cable  78  of  FIG. 4  and/or cable  78  may be implemented using a cable such as cable  36  of  FIG. 3 . The example of  FIG. 4  is merely illustrative. 
       FIG. 5  is a flow chart of illustrative steps involved in using test system  76  of  FIG. 4 . At step  92 , cable  36  may be coupled between device under test  10  and test equipment  30 - 1 . Test equipment  30 - 1  may then load a test program onto device under test  10  using the USB path in cable  36 . The USB path may also be used in conveying test logs and other test data from device under test  10  to test equipment  30 - 1 . The UART path in cable  36  may then be used by test equipment  30 - 1  to perform one or more tests on device under test  10  (e.g., tests of audio circuitry, video circuitry, wireless circuitry, or other components in device under test  10 ). During these tests, the UART path may be used to convey test commands from test equipment  30 - 1  to device under test  10  and may be used to convey corresponding test results from device under test  10  to test equipment  30 - 1 . 
     During testing at test station TS 1  with test equipment  30 - 1 , yellow indicator light Y on cable  36  may be illuminated (e.g., by flashing) to indicate to the operator that tests are being performed. Once testing is complete, the red or green indicator light may be illuminated to indicate a fail or pass condition, as appropriate. If the red indicator light is illuminated to indicate that tests have failed, appropriate actions may be taken at step  102  (e.g., the device under test may be scrapped, reworked, or retested). 
     If testing succeeds (i.e., the green indicator light is lit), testing can proceed to step  94 . During the operations of step  94 , the operator may connect device under test  10  to test equipment  30 -K in one or more intermediate test stations TSK and can use the UART path in cable  36  (or in cable  78 ) to convey test commands and test results between test equipment  30 -K and the device under test. The yellow indicator light may be illuminated to indicate the presence of active testing. Additional tests may be performed on one or more additional intermediate test stations, as indicated by line  98 . If tests fail, the red indicator light may be illuminated and appropriate actions taken at step  102 . If tests succeed, the green indicator light may be illuminated and processing may proceed to final test station TSN. 
     At final test station TSN, test equipment  30 -N may perform any desired final tests using the UART path in cable  36 . The yellow status indicator light may be illuminated during tests. If testing fails, the red indicator light may be illuminated and appropriate actions may be taken at step  102 . If testing succeeds, test equipment  30 -N may load a customer-ready operating system onto the device under test using the USB path in cable  36  and the green indicator light may be illuminated. The device into which the operating system has been loaded may then be shipped to a customer (step  100 ). 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20110513
Publication Date: 20151013
Grant Date: 20151013
Priority Date: 20110513
Inventors: BHATNAGAR ANUJ
MCPEAK JAMES L.
SOBAJIC SRDJAN
FONG NELSON
Assignee: APPLE INC
CPC Classifications: [{"code": "G01R31/2844", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01R31/2844", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 47142449