Background technology:
The function of integrated chip (IC:Integrated Circuit) becomes from strength to strength, being accompanied by technology also improves constantly, developed into submicrometer processing, simultaneously the pin of IC is more and more, and that printed circuit board (PCB:Printed Circuit Board) wire distribution distance becomes is more and more littler, structure becomes increasingly complex.Utilize the needle-bar (bed-of-nail) of mechanical probes test to be difficult to contact like this with node on the circuit board, the contact point space of leaving needle-bar for is more and more littler, make on-line testing (ICT:In Circuit Test) method more and more difficult by means of the needle-bar anchor clamps, because utilize mechanical probes to be difficult to touch the lead-in wire of these highdensity PCB circuit boards, and this testing apparatus has become very expensive, influence production and cost of development.
The IEEE1149.1-1990 standard is also referred to as JTAG (Joint Test Action Group) standard or boundary scan standard, and the architecture of test access mouth and boundary scan body is described and stipulated to this standard in detail, is a kind of boundary scan technique standard.Boundary scan technique is the scan chain on application integrated circuit border, carries out scan operation and to its measuring technology of observing and controlling.At present, device production manufacturer is the occupation rate of contending for markets both at home and abroad, all adopts the JTAG standard one after another in integrated circuit (IC) design with in making, and the required hardware resource of boundary scan test is integrated in the chip, and the Boundary-scan test technology supporting platform is provided.
Adopt boundary scan testing equipment and to form PCB boundary scan testing is provided, solve the difficult problem that the ICT method of testing runs in IC and PCB test for the IC that has boundary-scan function by this IC.Each IC that has boundary-scan function has a test access mouth (TAP:Test Access Port), and five signals of this interface are defined as test data input (TDI:Test Data Input), test data output (TDO:Test Data Output), test pattern selection (TMS:Test Mode Select), test clock (TCK:Test Clock) and test reset (TRST:Test Reset) respectively.On a PCB, just constitute " daisy chain " structure by TAP mouth TDI, the TDO signal of two or more IC are connected in series successively, adopted boundary scan testing (BST:Boundary Scan Test) method can detect the IC internal circuit on the intensive wiring PCB and the fault of external interconnect line thereof efficiently.Boundary scanning test method can also can be located PCB and go up the device whether certain position welds mistake like this by the ID value of reading device and the information such as version number of device simultaneously.
The basic thought of BST is the shift register cell of each I/O (I/O) pin place increase near device.At test period, these register cells are used to control the state (high or low) of input pin, and read the state of output pin, utilize this basic thought just can test out the quality and the interconnective correctness of device in the circuit board.And the ID value that can recognition means and the information such as version of device avoid welding wrong device.In normal work period, these additional shift register cells are " transparent ", do not influence the operate as normal of circuit board.
Technology relevant or close and patent with the technology of the present invention:
1, domestic: number of patent application is 01128718.7, and denomination of invention is: large scale integrated circuit (LSI) boundary scan and test system.The main contents of this invention are divided into software and hardware two parts.Software section is JTAG Builder IDE; Hardware components is based on the boundary scan testing interface card of pci bus.The major function of this invention is test I C or LSI.Can not test PCB and go up the interconnected situation of IC.
2, external: the patent No. is US5751737, and denomination of invention is: Boundary scan testing device (is translated into: the boundary scan testing device).This summary of the invention is the boundary scan testing device of a special use, and this device can carry out the combinational logic test to boundary-scan device, lays particular emphasis on the functional test that circuit itself is realized, is not used in the interconnected test between the device.In addition because this invention is special-purpose testing apparatus, complex structure, cost an arm and a leg, difficult quilt is promoted.
Summary of the invention:
At above-mentioned described technology and existing testing apparatus situation, the invention provides a kind of device that utilizes the parallel port of computer resource to carry out boundary scan.Utilize this device, can carry out boundary scan testing, thereby improve testability, the raising test coverage of each function veneer in the communication apparatus greatly printed board and components and parts thereof.In conjunction with traditional ICT method, just can more comprehensively test printed board and components and parts thereof.
Integrated circuit boundary scan testing device provided by the invention, be to utilize parallel port of computer to carry out the device of boundary scan testing, comprise: the physical layer interface module, realize driving to bottom hardware under the Windows, make application program to carry out read-write operation to the hardware port of bottom; The preliminary examination module realizes the preliminary examinationization to parallel port of computer and test logic, simultaneously the buffer zone of definition carry out preliminary examinationization, and parallel port of computer is verified; The test vector generation module generates test vector file automatically according to relevant test vector generating algorithm; Test module is input to pcb board to be measured with the test test vector, reads test result; Fault analysis and locating module according to test result, provide the position at fault type and fault location place; The JTAG hardware interface module realizes driving and isolation to the jtag interface signal.
The present invention can also comprise: PCB net meter file analysis module, and the PCB net list file of input is analyzed and handled; Boundary Sweep Description Language (BSDL:Boundary Scan Description Language) file analysis module, the BSDL file of BST device in the phase-split network table, draw information such as BST order that this device supports, BSC register length, BSC steering logic relation, for test vector generation and test execution used.
Adopt technical scheme of the present invention, make full use of the PC own resources, auxiliary simultaneously promptly by establishment PC boundary scan application program and PC parallel port with the jtag interface hardware unit, come Devices to test is carried out boundary scan testing.Compare with existing invention, not only can carry out boundary scan testing, and can carry out boundary scan testing whole pcb board to the device on the pcb board to be measured.This installation cost is low, is easy to promote, and saves development costs, more can improve the qualification rate that pcb board is produced, and improves pcb board greatly and produces testability.In addition, for the scene of engineering maintenance or equipment operation, use the technical solutions according to the invention can online easily location and search fault.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described.
Fig. 1 is the TAP controller state process flow diagram of IEEE 1149.1 definition.It is principle of the invention foundation.
Fig. 2 is a kind of embodiment and the workflow diagram of device of the present invention.Start human-computer interaction interface 1, just the program of the initialization section of while start-up routine.Input PCB net list file and BSDL file are carried out the analysis of two class files respectively: net list file analysis module 2, BSDL file analysis module 3.Carry out test vector generation module 4 according to result then and generate test vector two class file analyses.Execution test module 5 is given test vector and is treated examining system 9 by physical layer interface module 6 and JTAG hardware interface module 7.Execution module 5 obtains execution result and gives fault analysis and locating module 8 simultaneously, shows test results on human-computer interaction interface 1 at last.
If generate vector file by other vector generator, can go to save PCB net meter file analysis module and Boundary Sweep Description Language file analysis module in the device of the present invention.
Below each module is elaborated:
1, user interface
Graphic user interface is based on the interactive window of Windows operating system, and friendly man-machine interface is provided.For test process provides input, output function mode.
2, initialization module
The main preliminary examinationization that realizes parallel port of computer and test logic carry out preliminary examinationization to the buffer zone of definition simultaneously.This function also comprises the parallel port of computer checking, is used for judging whether it is available.When verification method is the parallel port of computer initialization, the TDI and the TDO of jtag interface hardware components got up with the wire jumper short circuit, can come automatic diagnosis computer parallel port, jtag interface signal whether available by program.Verify, disconnect above-mentioned wire jumper and get final product operate as normal.
3, physical layer interface module
The major function of this interface module is the driving that realizes bottom hardware under the Windows, here mainly be that parallel port to computing machine conducts interviews, api interface is provided for the testing execution module of application program, makes application program to carry out read-write operation the hardware port of bottom.
4, net meter file (PCB net meter file) analysis module
The PCB net list file of input is analyzed and is handled.PCB net list file is that the schematic diagram instrument generates automatically, meets certain standard and form, as Protel98 etc.This program module, the exception error that can point out the net list file to occur.File analysis obtains PCB node number, network and connects situation according to net list, and the device with BST function connects and distribution situation at network node.Be test vector generation module and test result diagnosis usefulness.The pin title of device definition must be named according to the given definition of device manufacturer in the schematic diagram component inventory because in the net list file for the device pin title definition rely on the schematic diagram component inventory in for the definition of the pin title of related device.
5, SDL file analysis module
The BSDL file of BST device in the phase-split network table draws information such as BST order that this device supports, BSC register length, BSC steering logic relation.For test vector generate and test execution used.
The BSDL file of device is to be provided or downloaded from the website of related device manufacturer by device manufacturer to obtain, the BSDL file must meet the regulation of IEEE Std 1149.1, because BSDL is the subclass of VHDL (VerilogicHardware Descrition Language), so can be with reference to IEEE Std1076-1993.This program module, the exception error that can point out the BSDL file to occur.Define and the inconsistent place of BSDL file description for device pin if run in the net list file, need automatically or manual modification net list file relevant portion.Be that the net list file must be consistent with the BSDL file of this device for the definition of device pin, otherwise just can not generate test vector.
6, test vector generation module
Only under prerequisite, could generate test vector file automatically according to relevant test vector generating algorithm to PCB net list and relevant BSDL file correct analysis.
The method that test vector generates: find the number of device interconnecting relation, interlink node by the analysis result of net list file, and generate the number of test vector according to the interlink node number by the related algorithm decision.Go out pin title or the number of pins and the BSC sequence number corresponding relation of the number of boundary scan test command that device supports and length thereof, boundary scan source (BSC:Boundary Scan Cell), control between the BSC and input/output relation, interlink node by the BSDL file analysis.Can use " MINIMUM WEIGHT sequence ", " maximum independent set " scheduling algorithm to generate the final test vector of using automatically by application program at last, follow the generation of test vector, the test result of expection also produces thereupon.
6, examination execution module
Application program is by being inserted into the JTAG hardware unit of PC parallel port, after test code streams (test vector) process and string conversion, be input to pcb board to be measured successively serially, the TAP state transition of this process need be in strict accordance with the state flow chart of TAP controller shown in Figure 1.When with test instruction EXTEST write command register, and after carrying out UPDATE_IR, just can read test result by the TAP mouth once more.
8, barrier is analyzed and locating module
Through the test result after testing, at the inconsistent fault of test result and expected results, provide the position at fault type and fault location place: certain pin of certain chip according to test vector.
9, JTAG hardware interface module
JTAG hardware interface device, main driving and the isolation that realizes jtag interface signal (TDI, TDO, TCK, TMS and TRST).
The jtag interface hardware unit can directly be inserted on the parallel port of computing machine, and its power supply is to be supplied with by external power supply, also can directly supply with by the jtag interface of pcb board to be measured.This device is realized driving and the isolation to TAP interface signal (TDI, TDO, TCK, TMS and TRST).At first the signal process buffering of the parallel port of computing machine transmission drives the TAP interface signal of back to pcb board to be measured, and the while isolates when reverse.Secondly, the output signal of board under test TAP interface and computer parallel port reception also carry out buffer compartment from, can protect the parallel port and the Devices to test of computing machine like this.Hardware components also comprises the signal indicating section simultaneously, is used to indicate the state of jtag interface signal.
Fig. 3 and Fig. 4 are the application examples of two kinds of embodiments of the present invention.Their difference is that what Fig. 3 imported " PC+application program " 102 is the BSDL file 101 of device and the net list file 100 of pcb board.What Fig. 4 imported " PC+application program " 102 is the vector file 201 of device, and this vector file is to be produced by other vector generator.Application program is the boundary scan testing program, and it mainly is made up of physical layer interface module, initialization module, vectorial generation module, testing execution module and fault analysis locating module, finishes boundary scan testing jointly.Wherein the physical layer interface module adopts WinDriver (V5.05) software guide (can support the Windows operating system of current all nominally issueds of Microsoft) to finish the visit to bottom hardware.
Mainly be main the explanation below with Fig. 3.
Enforcement is carried out boundary scan to pcb board to be measured, confirms at first whether pcb board supports boundary scan when design.The pcb board to be measured 9 of Fig. 3 has been linked as the BST device " daisy chain " (pcb board to be measured 9 of Fig. 4 is identical therewith) when design, be the TDI that the TDO of previous device 107 in the chain connects next device 108, the TDI of first device 107 is the TDI of TAP mouth 106 in the chain, and the TDO of last device 109 in the chain is the TDO of TAP mouth 106.
Implementing that pcb board to be measured is carried out boundary scan, jtag interface device 104 is coupled together by parallel port 103 and PC 102, can what can start that boundary scan testing program on the PC detects parallel port 103 first this moment operate as normal, if operate as normal then can continue following work.Connect with the TAP mouth 106 of 10 core flat cables 105 then with pcb board 110 to be measured.
Implementing that pcb board to be measured is carried out boundary scan, carry out the interconnected test of BST device on the pcb board, device is prepared the BSDL file 101 of " daisy chain " last all BST devices on the pcb board 110 to be measured and the net list file 100 of this PCB correspondence.By correct BSDL file 101 and the net list file 100 of boundary scan testing procedure Selection input, relevant option is set, start test function, application program is according to state machine shown in Figure 1, and control TAP mouth signal is exported corresponding test result at last.Application program output failure message when fault is arranged.
Implementing that pcb board to be measured is carried out boundary scan, carrying out on the pcb board certain BST device as 108 close betas own, the BSDL file of input device under test.This moment can be with 107 and 109 enforcement BYPASS instructions in " daisy chain ", implement INTEST or RUNBIST instruction to 108, simultaneously this device is aided with outside pumping signal, so just can carry out close beta to 108, test finishes, and application program is caught test result by boundary scan register.
Implementing that pcb board to be measured is carried out boundary scan, carry out the welding correctness test of device on the pcb board, the BSDL file of input device under test, whole BST scan path is carried out sweep test, read related device ID value and version number, the information that should weld device during with design compares, and judges whether the pcb board fixed position has welded correct device.Iff some devices are tested as 108,107 and 109 enforcement BYPASS in " daisy chain " can be implemented IDCODE to 108 and instruct, only obtain 108 information.Application program information automatic and device reality compares, and provides test result.
Fig. 5 is a jtag interface device 306, a side relevant with parallel port 301 got relevant data line and ground wire 302 from the parallel port of PC, wherein data line drives the input signal 307 (comprise TDI, TMS, TCK and TRST) of 304 backs, back as TAP mouth 309 through buffering.The ground wire of PC parallel port directly is connected with the ground wire of TAP mouth.Be connected with the BUSY line 303 of PC parallel port 301 from 304 backs through buffer compartment from TAP mouth 309 output signals 308 (TDO) in addition.In addition: the state indication 305 of this device can show the signal condition of TAP mouth.