American Patents LLC v. Mediatek, Inc. et al

Western District of Texas, txwd-6:2018-cv-00339

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2 EXHIBIT 4 Case 6:18-CV-00339-ADA Document US008996938B2 (12) United States Patent Dervisoglu et al. (10) Patent No.: (45) Date of Patent: US 8,996,938 B2 "Mar. 31, 2015 (54) ON-CHIP SERVICE PROCESSOR (58) (75) Inventors: Bulent Dervisoglu, Mountain View, CA (US); Laurence H. Cooke, Los Gatos, CA (US); Vacit Arat, Los Altos Hills, CA (US) Field of Classification Search CPC ........... G06F 11/3495; G06F 11/3466; G06F 2201/88; G06F 11/3409; G06F 11/364; GOIR 31/31705; GOIR 31/31723; GOIR 31/318385 USPC ....... 714/733, 726, 727, 729, 39, 30; 703/28; 324/754.07, 750.3 See application file for complete search history. (73) Assignee: Intellectual Ventures I LLC, Wilmington, DE (US) (56) References Cited (*) Notice: U.S. PATENT DOCUMENTS Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 90 days. This patent is subject to a terminal dis- claimer. 3,761,695 A 9/1973 Eichelberger 3,783,254 A 1/1974 Eichelberger 3,784,907 A 1/1974 Eichelberger (Continued) OTHER PUBLICATIONS (21) Appl. No.: 13/027,009 (22) Filed: Feb. 14, 2011 (65) Prior Publication Data US 2012/0011411 A1 Jan. 12, 2012 "BIST TPG for Faults in System Backplanes"; Proceedings of the 1997 IEEE/ACM International Conference on Computer-Aided Design, 1997, pp. 406-413. (Continued) Primary Examiner - David Ton (74) Attorney, Agent, or Goldstein & Fox PLLC Firm — Sterne, Kessler, (63) Related U.S. Application Data Continuation of application No. 12/717,391, filed on Mar. 4, 2010, now Pat. No. 8,239,716, which is a continuation of application No. 11/424,610, filed on Jun. 16, 2006, now Pat. No. 7,836,371, which is a (Continued) 185 (51) Int. CI. GOIR 31/28 (2006.01) GO1R 31/3185 (2006.01) (Continued) (52) U.S. CI. CPC .. GOIR 31/318572 (2013.01); GOIR 31/31705 (2013.01); GOIR 31/31723 (2013.01); GOIR 311318385 (2013.01); GOIR 31318566 (2013.01) USPC 714/726; 714/727; 714/729 (57) ABSTRACT An integrated circuit is described that includes a stored pro- gram processor for test and debug of user-definable logic plus external interface between the test/debug circuits and the component pins. The external interface may be via an existing test interface or a separate serial or parallel port. Test and debug circuits may contain scan strings that may be used to observe states in user-definable logic or be used to provide pseudo-random bit sequences to user-definable logic. Test and debug circuits may also contain an on-chip logic analyzer for capturing sequences of logic states in user-definable cir- cuits. Test and debug circuits may be designed to observe states in user-definable circuits during the normal system operation of said user-definable circuits. 22 Claims, 20 Drawing Sheets SPU 101 210 SIO Scan Control Analysis Engine Micro- processor BIST engine 217 Parallel I/O TAP 216 Range Check Interrupt Handler Test Bus Interface Buffer Memory Test Bus Interface 219 220 213 1 221 214 218 - --- 203 204 Trigger Test Bus 201 Analog Probes System Bus 104 105 202 Scan string 403 Core Block Digital Probes Test Wrapper 106 102 2 U.S. Patent Mar. 31, 2015 Sheet 7 of 20 US 8,996,938 B2 Test wrapper 102 305~0 306–0 test 3097.. Probefout todotcodaco Scan out 10 - - - - Scan FF 300 - - - - Data in 302- Probe -----Scan CERTACITO ---- Data out -307 303 in 301 304 308 --- Preferred Embodiment of Block Input/Output Port Connector FIG. 4a 2 U.S. Patent Mar. 31, 2015 Sheet 8 of 20 US 8,996,938 B2 000 be 1 Scan chain 403 Data out W daar WWW. R ANA 1000000000000-00000000008 316 confirmarevom 311 romanem317 314 scap out Scanft scan in probe put probe in 315- Data in 312 - 313 တွင် 3 DOC mormoon w wannee 320 Pooooooooooooooooooooooooooooooo C hod Figure 46 Chai 2 U.S. Patent Mar. 31, 2015 Sheet 9 of 20 US 8,996,938 B2 deces Hoool SOON Scan out Data out ScanSlave and Scan Slave Me Data Slave ter Figure 5 (prior art) H NAALAMU verwowwwwwww Master 400000 cocooooooooooooooooooooo Scan- Data can Blement with Scan Clk B Scan Cik A Scan in Data in System Cik set doodle Soooo 2 U.S. Patent Mar. 31, 2015 Sheet 10 of 20 US 8,996,938 B2 Threshold check 600 - 109 H Figure 6b mw wykonane 603 Figure ba 9+V Owoh Law 601 - 602 2 U.S. Patent Mar. 31, 2015 Sheet 11 of 20 US 8,996,938 B2 +V 602 H FIG. 6C 2 U.S. Patent Mar. 31, 2015 Sheet 12 of 20 US 8,996,938 B2 700 Ground bounce 701. ܚ ܗ ܢܫ ܚ ܝ ܚ ܗ ܚ ܚܝ ܚ ܚ ܝ ܚ ܝ ܚ ܚ ܚ ܚ 4 мм мм мм мм мм мм мм ма? Quiet 705 Ground set yang 702 wo Figure 7 704 NARA Reset 706 703 Local Ground 712 U.S. Patent Mask Shift Register 713 715 Pattern Shift Register Mar. 31, 2015 - ----------- ----- -- --- -- --- --- --- Mixed BISTI Functional Scan Vectors -- Sheet 13 of 20 2 - - - - - - - - - - - - - Polynomial Register ti US 8,996,938 B2 FIG. 8 U.S. Patent Scan 2013090 Variable EIE Variable bosona Probe Inputs 801- 9000000000000000 Awwwwwwwww Wariable EIFO. Variable EIED. "804 pococool Mar. 31, 2015 NOWANYAMARANTOWN MW A fro Sodancora nonn o scono Net 802 NEMA MANUAL Digital PLL COOCOOOOOOOOOOOOOOOOOOOOO00000000000000000000000OOOOOOOOOOOoo 814 803 ooooooooooooooooooo Figure 9a 2 812 ---- Sheet 14 of 20 - „Variable FIFO 229922909 AO wwwwwwwwwwmwm GARAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA para ARRARARARE ANDREOLAUAAALAAAAA9000000 AAAALALALALOONDIOKURIKULUNURLARIVOODICE COLOR COMM E Decode sa 66666 6 66666666666666666666666666sssssssss алада Count Register 813 Ooooo00000000000000000000000000000000oooooooooooo000000OOSSSOOOO000000000000 8 804 Figure 95 US 8,996,938 B2 2 U.S. Patent Mar. 31, 2015 Sheet 15 of 20 US 8,996,938 B2 00000 5000రరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరతరతరతరతరతరతతరతరకరకక కకకకకకక - ***** Load 820 Address A Address Counter Start Address 822 Buffer Memory Figure 9c 821 814 Stop Counter 218 wwwData input From Variable FIFO 804 Latched Trigger 824 woosoboscoobsosaksonooms అదరగరుంగురంగురందరరరరరరరరరంగంలో 2 U.S. Patent Mar. 31, 2015 Sheet 16 of 20 US 8,996,938 B2 838 824 835 Trigger 835 837 834 ņ831 830 T[O] T[n-1] T[n] FIG. 9d PE============EEEE 832 833 Probe 11 Probe NDA 2 U.S. Patent Mar. 31, 2015 Sheet 17 of 20 US 8,996,938 B2 ooo 218 Load AROURORAAAARAR Aboucusu Address 2000 099209999999999999992000000ogogogogogorosos2222 Address Counter Summmmmmm Start Address voorroroon 822 Buffer Memory 821 Data input cacaocooooooooooooooooooo soggerespasangan penggunaan From Probes NA RVARNARVA ARARAANAAAAAAAAAAA Figure 10 Stop Counter was Stop Count VAAKUNNANVA assesser Clock 2009098000000000000 824 Latched trigger ext will 2 U.S. Patent Mar. 31, 2015 Sheet 18 of 20 US 8,996,938 B2 Buffer Memory LA Buffer Memory 218 814 1000 Direct-Probe Pipeline FIG. 11 PSE 1001 CF 1001 Inserted SRL Functional SRL Combinational Logic ch 2 U.S. Patent Mar. 31, 2015 Sheet 19 of 20 US 8,996,938 B2 Buffer Memony LA Buffer Memory 2013 38 oone Kococco KKXXKKK B domain Direct-Probe Channels WOOOO0000000 1001 mamy Figure 12 ကာ door COVORO AIR Mux'ed-Probe Channel SD37 U.S. Patent 1109 P10 1107 p2oT 1105 Mar. 31, 2015 ... 1110.....1108 1104 D 1101 SI O A_clk 1101 11114 Cf A_clk - 1102– B_clk A L1 27 2 1109 P_clk Sheet 20 of 20 1106 Scan_Mode 1103 1112 1111 1000. . . . . . . . . . . . . . FIG. 13 US 8,996,938 B2 2 US 8,996,938 B2 Oy OPA 1 ON-CHIP SERVICE PROCESSOR To address the problems of the testing of integrated cir- cuits, special features are being included in many IC designs. CROSS REFERENCE TO RELATED For example, one standard technique is "scan" whereby, cer- APPLICATIONS tain internal flip-flops, which are connected to various s selected points of the IC, are also connected to form a serial This application is a continuation of co-pending U.S. shift register when the IC is configured in a test mode. patent application Ser. No. 12/717,391, which is a continua- Straightforward serial shift (i.e., scan) operations are utilized to load the flip-flops with desired values, or to read out their tion of U.S. patent application Ser. No. 11/424,610, filed Jun. present values reflective of the logic states of the selective IC 16, 2006 (which issued as U.S. Pat. No. 7,836,371), which is points. Such ICs require special features to reset the flip-flops a continuation ofU.S. patent application Ser. No. 11/261,762, 10 (i.e., bring the IC to a known starting state). However, the size filed Oct. 31, 2005 (which issued as U.S. Pat. No. 7,080,301), of integrated circuits has grown to the point where it has commonly-assigned, and incorporated by reference in its become inefficient and expensive to test and debug ICs using entirety. That application is a continuation of U.S. patent solely conventional scan techniques. application Ser. No. 10/767,265, entitled, "On-Chip Service Furthermore, variations of the serial scan technique Processor." filed on Jan. 30, 2004 (which issued as U.S. Pat. 15 include the use of so-called "shadow registers." IC internal No. 6,964,001), commonly-assigned, and incorporated by signal states are captured in a duplicate copy, i.e., the shadow reference herein in its entirety. That application is a continu register, of certain internal registers. The shadow registers are ation of U.S. Patent Application No. 09/275,726, entitled, interconnected by a dedicated internal scan chain. A prede- "On-Chip Service Processor," filed on Mar. 24, 1999 (which termined event can trigger a snapshot of the internal state issued as U.S. Patent No. 6,687,865), commonly-assigned, 20 values in the shadow registers and the dedicated scan chain and also incorporated by reference herein in its entirety. That shifts the captured signal state without affecting the system application, in turn, is entitled to the priority of U.S. Provi- operation of the IC. However, this approach has several defi- sional Patent Application No. 60/079,316, filed on Mar. 25, ciencies. First, only a single snapshot can be captured and 1998. shifted out with each trigger event. This greatly hampers 25 debugging the IC since there is not much visibility of the BACKGROUND OF THE INVENTION system activity around a point of interest identified by the trigger event. Secondly, the snapshots can be taken only of The present invention is related to the testing and debug- those signals in registers which have a shadow register coun- terpart. Since a shadow register effectively doubles the cir- ging of electronic systems, and, in particular, to on-chip cir- cuitry for the register, this approach is very costly to imple- cuits for the test and diagnosis of problems in an integrated 30 ment on a large scale in the IC. circuit. Another test and debug design for ICs is found in a stan- Heretofore, logic analyzer probes have often been used in dard, the IEEE 1149.1 Test Access Port and Boundary-Scan the testing and debugging of electronic systems. The logic Architecture, which prescribes a test controller which analyzer probes were coupled to the external pins of compo- responds to a set of predetermined instructions and an instruc- nents of a digital system in order to capture the sequence of 35 tion register which holds the present instruction which the signals after a predefined event (or time stamp) occurs. The controller executes. Each instruction is first loaded into the captured signals can then be examined to verify correct sys- instruction register from a source outside the IC and then that tem behavior or, alternatively, to identify the time and the instruction is executed by the controller. While having some nature of erroneous behavior in the system. advantages of versatility and speed, the standard still binds Furthermore, in the designs of large electronic systems, 40 test and debug procedures to the world external to the IC and arate consoles, or service processors, have often been thus, limits its performance. incorporated into the circuit boards of the system. These The present invention recognizes that while the advances in separate processors have a number of useful functions, IC technology have helped to create the problems of testing including the control of scan strings in the system; the origi and debugging an IC, the advances also point the way toward nation of diagnostic signal probes to run on the system, and so 45 solving these problems. In accordance with the present inven- forth. The service processors also have diagnostic and scan tion, special on-chip circuits are used to observe the internal debug features, including access to the internal registers and workings of an IC. These circuits operate at internal IC clock memory within the system. The service processors have also rates so that the limitations of the frequency of signals at the been used to bring-up the main system during its power up IC input and output (1/0) boundary are avoided. Many more phase. All of these functions have been useful to system 50 points in the IC system are accessed than is feasible with designers for the design, test and debugging of electronic conventional external test and debug processors. Thus the systems. present invention offers advantages which exceed the On the other hand, more and more digital systems, or parts straight-forward savings in chip space due to miniaturization. of digital systems, are being integrated in a single component. Additionally, the present invention reduces the amount of test The resulting complexity and lack of observability of an 55 logic which might have been required elsewhere on the chip. integrated circuit poses serious problems for the test, debug The present invention also permits the coupling of probes and bring-up stages of the integrated circuit (IC). For to internal IC points. The points may be selected from a larger example, observation at the IC component pins of the behav- number of internal points that may be observed with an exter- ior of an IC system is increasingly difficult. The IC compo- nal logic analyzer. Besides the greater observability of the nent pins may be very far (in terms of logic hierarchy) from 60 internal operations of the IC, the present invention also the actual points of interest. The extremely high frequency of improves the accuracy of the observations, as compared to an digital IC operations and the frequency filtering effects of the external logic analyzer. large capacitance of the external logic analyzer probes, often prevents a logic analyzer from capturing signals reliably and SUMMARY OF THE INVENTION precisely. There is always an uncertainty regarding the accu- 65 racy of signals captured by an external logic analyzer com To achieve these ends, the present invention provides for an pared to the actual signals values within the IC. integrated circuit logic blocks, a control unit, a memory asso- 2 US 8,996,938 B2 30 Hans. ciated with the control unit and a plurality of scan lines. The tecture); FIG. 4b is a circuit diagram of a block scan connector memory holds instructions for the control unit to perform test for scan strings for observing test points inside a block along and debug operations of the logic blocks. The scan lines are a scan chain; responsive to the control unit for loading test signals for the FIG. 5 is a circuit diagram of a scan flip-flop in the FIG. 4b logic blocks and retrieving test signal results from the logic 5 circuit diagram; blocks. The test signals and the test signal results are stored in FIG. 6a is a circuit which generates an out-of-range detec- the memory so that the loading and retrieving operations are tion probe signals for range probes; FIGS. 65 and 6c are the performed at one or more clock signal rates internal to the transistor-level circuits of inverters in FIG. 6a.; integrated circuit. The integrated circuit also has a plurality of FIG. 7 is a circuit which generates ground-bounce detec- probe lines which are responsive to the control unit for car- 10 tion probe signals for range probes; FIG. 8 is a block diagram of a Built In Self-Test (BIST) rying system operation signals at predetermined probe points engine of the FIG. 2 SPU; of the logic blocks. The system operation signals are also FIG. 9a is a block diagram of an input aligner portion of stored in the memory so that the system operation signals are Analysis Engine of the FIG. 2 SPU; FIG. 9b is a detail of the retrieved at one or more clock signal rates internal to the 15 15 FIG. 9a Analysis Engine's input aligner; FIG. 9c is a block integrated circuit. diagram of the Analysis Engine's memory addressing struc- The present invention also provides for an integrated cir- ture; FIG.9d is a block diagram of the trigger logic portion of cuit which has an interface for coupling to an external diag- the Analysis Engine; and nostic processor, a unit responsive to instructions from the FIG. 10 is a block diagram of another embodiment of the external diagnostics processor, a plurality of probe lines 20 Analysis Engine's memory addressing structure; coupled to the unit, and a memory coupled to the unit and to FIG. 11 shows a probe string connection of probe points to the interface. In response to the unit, the probe lines carry the buffer memory using logic analyzer channels that are sequential of sets of system operation signals at predeter- implemented with probe storage elements (PSE); mined probe points of the integrated circuit and the system FIG. 12 shows an alternative probe string, connection with operation signals are stored in the memory at one or more 25 improved multiplexed PSEs which combine probe selection clock signal rates internal to the integrated circuit. The system and data capture functions; and operation signals are retrieved from the memory through the FIG. 13 is a block diagram of the improved PSE of FIG. 12. interface to the external diagnostic processor at one or more DESCRIPTION OF THE SPECIFIC clock signal rates external to the integrated circuit. This EMBODIMENTS allows the external diagnostics processor to process the cap- tured system operation signals. General Organization of the Present Invention The present invention further provides for a method of In accordance with the present invention, a Service Proces- operating an integrated circuit which has logic blocks, a con- sor Unit (SPU) is incorporated within an integrated circuit. trol unit, a memory and a plurality of scan lines of the logic 35 Besides addressing the problems of testing and debugging the blocks. The memory is loaded with test signals and instruc- IC, the availability of a programmable unit, such as the SPU, tions for the control unit and the scan lines responsive to the which may load or unload the state variables into and from the control unit are loaded with the test signals for the logic user-definable logic in an IC, greatly simplifies the problem blocks at one or more clock signal rates internal to the inte- of resetting the IC and observing its current state. The SPU is grated circuit. The logic blocks are then operated at one or 40 implemented in the form of a basic stored-program control more clock signal rates internal to the integrated circuit and unit, such as a microprocessor, with a predefined instruction the resulting test signal results are retrieved from the logic set, a number of extended function units (EFUS), program, blocks along the scan lines at one or more clock signal rates data, and scratch pad memories, plus an input/output circuit internal to the integrated circuit. The test signal results are for loading and unloading the SPU memories with data/pro- stored in the memory at one or more clock signal rates internal 45 grams from the outside world. This allows the SPU to be to the integrated circuit; and the stored test results signals are programmed to execute a control program which interacts processed in the control unit responsive to the stored instruc with the various extended functional units to control various tions in the memory to perform test and debug operations of test and debug related activities on the IC. the logic blocks. Each EFU is designed to control a specific test or debug 50 feature and the EFU provides the control unit a general, BRIEF DESCRIPTION OF THE DRAWINGS programmable access to that feature. For example, one EFU may be designed to control the execution of serial shift opera- FIG. la shows a high-level diagram of an exemplary large tions along some or all of the internal scan chains of the IC. and complex integrated circuit. FIG. 1b shows the FIG. 1a The other EFUs may be enabled to interact with the scan integrated circuit with a Service Processor Unit (SPU), 55 chains, such as a predetermined algorithm to provide a Built- according to one embodiment of the present invention; In Self-Test (BIST) for an embedded Random Access FIG. 2 illustrates one embodiment for the architecture for Memory (RAM) block. The existing scan chains load and the SPU of FIG. 1b; unload the BIST patterns and results to/from the RAM block. FIG. 3a illustrates the coupling between test wrappers, The EFUs provide the control unit with a straight forward, scan strings, probe strings and range probes to a test bus; FI 3b is a circuit diagram of a test bus connector of FIG. 3a; EFU such that knowledge of low level details of the scan or FIG. 3c is an exemplary connection of multiple test bus BIST functions become unnecessary. connectors; With its program and data memories the SPU acts autono- FIG. 4a is a circuit diagram of a block input/output con- mously once its program memory has been loaded with the nector for test wrappers for observing test points outside a 65 desired instruction sequence. The SPU's program memory block along a boundary-scan chain (for example, IEEE may be loaded with the desired program instructions through 1149.1 standard Test Access Port and Boundary Scan Archi the SPU's interface to the external environment. Alterna- 2 US 8,996,938 B2 tively, the instructions may be stored in an on-chip Read Only The benefits of the logic analyzer EFU are such that for Memory (ROM) that has been provided to work as the SPU's certain ICs, only the EFU portion of the SPU is implemented program memory. on the IC. In this alternate embodiment of the present inven- In one embodiment of the present invention, an EFU. car- tion, the digital and analog probes are selectively enabled by ries out certain functions of a logic analyzer. A logic analyzer 5 a scan-chain which allows specific control signals to be captures and stores signal state values in a digital system loaded into these probe circuits. The scan chain also carries following the occurrence of a pre-defined event. The logic other control signals to be loaded into a trigger circuit which analyzer then analyzes the captured data and displays the starts and stops the data capture operations. Once the desired results for perusal. With the present invention, the capture and data has been captured into an on-chip RAM, the data is | 10 transported outside the IC for subsequent analysis and dis- storage functions are incorporated into the IC. The EFU play. which implements these functions captures and stores not a Implementations of the Present Invention As a starting single snapshot but a sequence (i.e., history) of signal values point, FIG. 1a is a diagram of an exemplary integrated circuit. using logic probes which are selectively coupled to desired The IC 100 is complex having a host processor connected by points in the IC logic circuits. The logic analyzer EFU is 15 a system bus to various circuit blocks, including a third party configurable to select the location, number and sequential core and other blocks adapted to the application of the IC. The depth of signal channels from a predetermined set of choices. IC also has a peripheral bus which is connected to the system Thus, each logic analyzer channel may be selectively coupled bus by a bridge. The peripheral bus is connected to other to more than one predetermined capture point by program- functional blocks, such as a user-developed core and so on. ming the control unit and hence, the EFU. A solution is 20 A preferred embodiment of the present invention to test provided for capturing the history of signal values at the and debug the complex IC of FIG. la is shown in FIG. 1b. internal points of the IC without having to provide each one of Added to the IC 100 is a Service Processor Unit (SPU) 101 these points with their shadow register counterpart. The cap- which is coupled to the IC system bus 105 and an added test tured data are stored in an on-chip Random Access Memory bus 104. Connected to the test bus 104 are test wrappers 102 (RAM). Transportation of the captured data out of the IC is 25 which provide test communication channels into selected performed later for analysis by an external computer which blocks 106. More details of the test bus 104 and test wrappers can reformat and display as required for diagnostics. The 102 are provided below. The SPU 101 provides a connection present invention has the benefit of enhanced data accuracy for an external diagnostics console 103 to view and test the with minimal cost overhead by separating the signal captured internal workings of the IC 100. storage function of a logic analyzer into the IC. 30 As shown in FIG. 2, the SPU 101 has several extended Two different types of logic probes may be used with the function units (EFUS), including a control unit, such as a logic analyzer EFU. One type of logic probe, termed the microprocessor 211, a buffer memory unit 218, an analysis digital probe, captures sequences of digital signals from inter engine 215, a scan control unit 222, an interrupt handler 221, nal points of the IC. Digital signal values flow from the which is further connected to a range check unit 220, a system internal capture point to a logic analyzer channel through the 35 bus interface 214, a test bus interface 213 and a built-in self digital probe. In its simplest form each digital probe has at test (BIST) engine 212, which are all interconnected by a least two input ports, a selection means and an output port that processor bus 219. The various EPUs are coupled to the is directly coupled to a logic analyzer channel. Digital probes processor bus 219 in any desired combination and order. To may also be constructed from a series of internal storage provide communication between the external world and the elements (i.e., flip-flops or latches) to form a pipeline to move 40 SPU 101, the bus 219 is also connected to a serial input/output the data from the capture points towards the logic analyzer (SIO) interface 210, a parallel input/output interface (PIO) channels. In this case, the movement of the data along the 216, and a test access port (TAP) 217. For example, the digital probe flip-flops is synchronized with an on-chip clock coupling between the IC 100 and the external diagnostics signal. Since the clock frequency also defines the maximum console 103, typically implemented using another computer, capture rate, the particular clock signal is selected based on 45 uses the TAP 217, the SIO interface 210 or the PIO interface the maximum desired capture rate. The digital probes used for 216. the logic analyzer EFU operate with the same electrical and Analog probe lines 201 are connected to the range check timing characteristics of the native signals of the IC. The unit 220 which processes their values to detect out-of-range digital probes are implemented in the same technology, with conditions which are then signaled to the interrupt handler the same functional logic circuitry, and under the same clock 50 221. The interrupt handler 221 also receives signals from timing, as the rest of the IC. Signals are therefor captured and trigger event lines 204 directly or from test bus 104 by way of propagated along the digital probes in exactly the same way test bus connections 203 to the interrupt handler 221. The as they are operated upon by the functional circuitry of the IC. signals on the trigger event lines 204 or test connections 203 This assures much greater accuracy of signal states captured are used to capture signal state values when predetermined by the digital probes. In contrast, logic probes used with an 55 (i.e., triggering) events occur. The interrupt handler 221 external logic analyzer must use trigger events and signal passes the captured values to the analysis engine 215. The test values that are visible external to the IC. The captured signal bus 104 is further coupled to test wrappers 102, which are values may differ significantly from the original (internal) individually wrapped around a number of predetermined values. blocks 106 on the IC 100. Each test wrapper 102 accesses the The logic analyzer EFU may use a second type of logic 60 input and output signals of a block 106. The test bus 104 is probe, termed an analog probe, which captures signal events also connected to scan string lines 403, which are connected representing the detection of signal integrity conditions, such to internal elements of a block 106. as ground bounce. Desired signal observation points are As shown in FIG. 3a, the test bus 104 forms a unidirec- coupled to analog detection circuits which produce digital tional loop with test bus connectors 401 selectively transfer- signals when particular signal conditions are detected. The 65 ring data betwe analog probe records these digital signal states in the logic test bus 104 is made up of multiple bit lines, where the number analyzer EFU. of the bits is determined by the requirements of the test све 2 US 8,996,938 B2 system. Through test bus connector 401, the test bus 104 is of the SPU 101. The control signal on the line 300 selects selectively connected to test wrappers 102, scan string lines whether the functional signal at data-in terminal 302 or the 403, probe string lines 402 and trigger lines 204. signal held in the scan flip-flop 301 is passed onto the data-out A test bus connector 401 which handles a one bit connec- terminal 307. When the control signal of the line 300 signal is tion between the test bus 104 and a test wrapper 102 is 5 not-asserted, i.e., normal mode, there is normal operational illustrated in FIG. 3b. A first multiplexer 421 has one of its signal flow between the data-in terminal 302 and the data-out input terminals connected to one of the lines of the test bus terminal 307. On the other hand, when the control signal on 104. The other input terminal is connected to a signal line of the line 300 is in asserted state, i.e., test mode, the current state the test wrapper 102. The output terminal of the multiplexer of the scan flip-flop 301 is passed onto the data-out terminal 421 is connected to an input terminal of a flip-flop 426 and to 10 307; the data-in terminal 302 and the data-out terminal 307 an input terminal of a second multiplexer 422, which has a are isolated from one another. The state stored in the scan second input terminal connected to the output terminal of the flip-flop 301 is also controls whether the signal at the data-in flip-flop 426. The output terminal of the flip-flop 426 is also terminal 302 or the probe-in terminal 303 is passed onto the connected to the line of the test wrapper 102, which is also in probe-out terminal 305. In this manner, data from another the form of a unidirectional loop. The multiplexer 421 selects 15 probe point which is connected to the probe-in terminal 303 either the data from the test bus 104 or the test wrapper 102; are selectively passed onto the probe-out terminal 305. The the second multiplexer 422 selects between the data selected signal state in the scan flip-flop 301 value is controlled and by the first multiplexer 431 or the data captured in the flip-flop observed using regular scan operations of the test wrapper 426 to place back onto the test bus 104. These selections are 102 through the scan-in and scan-out terminals 304 and 306. done under the control of SPU 101. The test bus connector 20 Of course, if observation of an input or output signal of the 401 is also be used for coupling a trigger line 204, probe string block 106 by a probe string 402 is not required, the multi- line 402 or scan string line 403 to a test bus 104 by connecting plexer 309 can be eliminated from the circuit 310. the desired signal line in place of the line of the test wrapper A scan string 403 is formed by serially connecting block 102 port as shown in FIG. 3b. scan connector circuits 320. One such circuit 320, which FIG. 3c shows an embodiment of coupling a trigger line 25 couples an internal element of a block 106 to the scan string 204, probe string 402, test wrapper 102 and scan string line 403, is illustrated in FIG. 4b. The connector circuit 320 has a 403 to three lines of the test bus 104. Other possible configu- scan-in terminal 314 and a scan-out terminal 316. The scan-in rations for the couplings include coupling the test wrapper terminal 314 of one connector circuit is connected to the 102 and scan string 403 onto separate lines of the test bus 104. scan-out terminal 316 of another connector circuit 320 to A test wrapper 102 is formed by serially connecting block 30 form a serial scan string 403. The block scan connector circuit I/O connector circuits 310. One such circuit 310, which 320 also has a data-in terminal 312 and a data-out terminal couples an input or output signal of a block 106 to the test 317 which provide an interstitial connection between internal wrapper 102, is illustrated in FIG. 4a. The connector circuit elements of the block 106. In the normal operation of the IC 310 has a scan-in terminal 304 and a scan-out terminal 306. 100, the connector circuit 320 is a simple path between the The scan-in terminal 304 of one circuit 301 is connected to the 35 internal elements in the block 106. The connector circuit 320 scan-out terminal 306 of another circuit 301 to form the serial also has a probe-in terminal 313 and a probe-out terminal 315 chain of a test wrapper 102. The connector circuit 310 also has which provide a path for probe signals from selected portions a data-in terminal 302 and a data-out terminal 307 which of the block 106 through the connector circuit 320 to observe provide an interstitial connection between a block 106 and the ction between a block 106 and the operations in the block 106. rest of the IC 100. In the normal operation of the IC, the 40 The block scan connector circuit 320 has a scan flip-flop connector circuit 310 provides a simple path between the 311 and a multiplexer 319. The data in terminal 312 and the block 106 and the rest of the IC 100. If the connector circuit scan-in terminal 314 form the inputs to the scan flip-flop 311. 310 is to provide an input signal to the block 106 during test The output from the flip-flip 311 include the scan out terminal operations, the data out terminal 307 is connected to the block 316 and the data-out terminal 317. The data-in terminal 302 is 106 and the data in terminal is connected to the rest of the IC 45 also connected to one input to the multiplexer 319. The probe- 100. If the block I/O connector circuit 310 is to receive an in terminal 313 forms a second input to the multiplexer 319 output signal from the block 106 during test operations, the whose output forms the probe-out terminal 315. A special data-out terminal 307 is connected to the rest of the IC 100 circuit is used for the scan flip-flop 311 (and the flip-flop 301 and the data-in terminal is connected to the block 106. The ofFIG. 4a). The circuit, which is shown in FIG.5 and is found connector circuit 310 also has a probe-in terminal 303 and a 50 in previous IC scan designs, has separate scan-slave and probe-out terminal 305 which provide a path for probe signals data-slave sections. The separation allows a state signal from selected portions of the block 106 through the connector which has been scanned into the scan flip-flop 311 to remain circuit 310 to observe operations in the block 106. unaffected by functional clock pulses that cause the flip-flop The elements of the connector circuit 310 include a scan 311 to capture signals on the data in terminal 312 so that they flip-flop 301 and two multiplexers 308 and 309. The data-in 55 appear in the data-slave section and on the data out terminal terminal 302 and the scan-in terminal 304 form the inputs to 317. The connector circuit 320 acts as a simple conduit for the flip-flop 301. The output from the flip-flip 301 include the signals within the block 106. At the same time, the previously scan out terminal 306 and one input to the multiplexer 308 scanned-in signal, which appears in the scan-slave section, having an output which forms the data-out terminal 307. The selects whether signals at the data in terminal 312 or the second input to the multiplexer 308 is connected to the data-in 60 output from another probe point which has been connected to terminal 302, which is also connected to one input to the the probe-in terminal 313 is to be passed onto the probe-out multiplexer 309. The probe-in terminal 303 forms a second terminal 315. A probe string 402 is created. Of course, if an input to the multiplexer 309 whose output forms the probe internal scan string 403 need not be connected to a probe out terminal 305. The control input of the multiplexer 309 is string 402, the multiplexer 319 can be eliminated from the the output of the scan flip-flop 301 (and is connected to one 65 circuit 320. input of the multiplexer 308). The control input of the multi A probe string 402 is formed by serially connecting the plexer 308 is a test control line 300 from the control unit 311 probe-in terminal of a connector circuit 310 and 320 to the - 2 US 8,996,938 B2 10 probe-out terminal of another connector circuit 310 and 320. identifies the bit positions whose values are selected from The probe string 402 typically has a set of selectively con predetermined bit patterns in mask shift register 713 versus nected probe points. However, only one probe point along the bit positions which receive the pseudo-random values each probe string 402 may be actively probed at any given generated by the LFSR 714. The output of the multiplexer 715 time. Thus the IC designer selects the probe points which are 5 is a combination of built-in-self-test and functional scan vec- to be connected along the same probe string 402 and deter tors. These features are useful because random vectors work mines the total number of probe strings 402 that are to be well only when the controls allow the random vectors to connected to the individual bits of the test bus 104. This exercise most of the IC section under test. If there are more structure allows the IC designer great flexibility to optimize than a few control lines, the probability of properly exercising the number of test bus 104 lines with respect to the number of 10 the logic under test with random vectors is very low. These simultaneously observable probe points in the IC. features also allow the SPU 101 to generate regularly repeat- The probes described above are digital probes. Two analog ing patterns, for example, periodic patterns that may be useful probes are illustrated in FIGS. 6a, 6b, 6c and 7. The range in a memory test may be generated by the SPU 101 that may check unit 220 receives inputs from the analog probes that output the data to the section of logic under test via the test bus comprise signals on a threshold check line 600 and a ground 15 or the system bus, whichever has been provided with a con- bounce line 700. The unit transmits these signals to the SPU nection to the SPU 101. 101. FIGS. 6a, 6b and 6c show the circuit which generate the Another EFU of the SPU 101 is the analysis engine 215. signal for the threshold check line 600. The circuit is used for FIG. Ia shows an embodiment of the analysis engine 215 detecting extended intermediate voltage levels. Such voltage which, under the control of the microprocessor 211, captures levels are most likely to occur on an on-chip bus, which is in 20 logic signals from the test bus 104. This is achieved by first contention among multiple circuit drivers. The analog probe setting either the scan flip-flops 301 of the block I/O connec- has two inverters 601 and 602, which are both coupled to an tor circuits 310 (FIG. 4a) or the scan flip-flops 311 of the Exclusive-NOR logic gate circuit. FIG. 6b is a transistor block scan connector circuit 320 (FIG. 4b) so that a boundary diagram depicting the low threshold inverter 601, and FIG. 6C connection or an internal point connection of the target block is a transistor diagram depicting the high threshold inverter 25 106 is selected for probing, respectively. Next, all flip-flops 602. These inverters 601 and 602 exhibit switching properties along the same probe string 402 are programmed (by the SPU characteristic of a very low internal voltage, and a very high 101) so that only signals from the selected probe point are internal voltage device, respectively. Normally, the circuit in allowed to flow through the probe string 402 and arrive at the FIG. 6a has a logic one (1) output level, but during transitions test bus connector 401. The multiplexer 421 and the multi- of the input signal, the outputs of inverters 601 and 602 may 30 plexer 422 in the test bus connector 401 (FIG. 3a) are con- remain in opposite states for a period sufficient to cause the trolled by the SPU 101 so that the signals on the probe string circuit to go to a logic zero (0) output level before returning to 402 are passed along to the test bus 104. Finally, all remaining the logic one (1) output level. This negative pulse can be test bus connector circuits 401 along the same bit line of the captured by the SPU 101. test bus 104 are controlled by the SPU 101 so that they pass FIG. 7 shows a schematic diagram of a ground bounce 35 the probe signals along test bus 104. This allows the selected detector circuit which generates the signals for a ground probe signal to arrive at the analysis engine 215 where it is bounce line 700. In this circuit, a quiet (and true) ground captured for subsequent off-line analysis. The input terminals terminal 701 is connected to an N-channel transistor 702, of a plurality of flip-flops 805, one for each bit line of the test which gate is driven by a local ground connection terminal bus 104, form the input port 802 of the analysis engine 215. A 703. A periodic clock on a Reset terminal 706, which is 40 digital phase locked loop (PLL) 802 has selectable clock controlled from the range check 220, clears a pair of NAND outputs 803 to each flip-flop 805 to tune when the data from gates configured as a SR latch 704, and charges a capacitor each probe point is to be captured. The output terminal of each 705 having one terminal connected to the Set input of the SR flip-flop 905 is connected to the input terminal of a variable latch. The second terminal of the capacitor 705 is connected First-In-First-Out shift register (FIFO) 804. to the quiet ground terminal 701. The N-channel transistor 45 FIG. 9b shows the circuit details of each variable First-In- 702 which is gated by the local ground discharges the Set line First-Out shift register (FIFO) 804, each having a number of of the SR latch 704, which flips the state of the SR latch 704 serially-connected register stages 812. Each register stage if the local ground falls above threshold. For example, a 812 has a multiplexer which, under control of a decoder 811, ground spike on the local ground may drive the local ground selects between the signal held in a flip-flop of that stage or below threshold. The frequency and duty cycle of the Reset 50 the incoming signal to the stage to place on the stage's output signal determines the magnitude and duration of a ground terminal. The shift depth of each variable FIFO 804 is pro- spike on the local ground to trigger the probe. A variety of grammable by the SPU 101 by setting a count register 810 for frequencies and duty cycles are created by the range check each bit feeding the analysis engine 215. The value in the 220 to determine the severity of ground spikes. When the count register 810 is decoded by the decoder 811. The result probe is triggered, the probe produces a negative (0) value 55 controls the number of register stages 812 until reset by the Reset signal on the terminal 706. bypassed. This compensates for the path delay differences Returning to the components of the SPU 101, FIG. 8 is a among the different probe points by realigning capture times preferred embodiment of the BIST engine 212. A polynomial of signals captured in the analysis engine 215. register 711 identifies the bits in a linear feedback shift reg- The analysis engine 215 also has trigger logic which con- ister (LSFR) 714 which are used to form an Exclusive-OR 60 trols the capture of data. FIGS. 9c and 9d show sections of the (XOR) function which generates pseudo-random values. The trigger logic, a programmable circuit which detects one or polynomial register 711 is set by the microprocessor 211, more events to stop the analysis engine 215 from capturing which also initializes contents ofthe LSFR 714. The output of new data. The data that has been captured up to that point is the LSFR 717 is connected to the inputs of a multiplexer 715 preserved in the buffer memory 218 of the SPU 101. The which also receives the outputs of a mask shift register 712 65 buffer memory 218 resides in the same address space as the and a pattern shift register 713. The output of the multiplexer RAM used by the SPU 101 but may be mapped to use high 715 is an input to the LSFR 714. The mask shift register 712 memory space in order to prevent interference with the 2 US 8,996,938 B2 11 instructions and data stored in low memory space. When the Program instructions and initial data values for executing analysis-engine 215 collects data, it may be allowed to write programs to implement the functions of the SPU 101 are over old data, keeping only as many most-recent cycles of loaded from the diagnostics console 103 (see FIG. 1b) into the data as the buffer memory 218 can hold. The size of the buffer buffer memory 218 of the SPU 101. Some of these programs memory 218 for the analysis engine 215 is determined by the 5 may access the system bus 105 or the test bus 104. A program designer of the IC. can control which test wrapper 102 is accessed by using the The trigger logic has a start address counter 820 and a stop test bus interface 213 in order to set control signals on the test counter 821, which are shown in FIG. 9c. These counters are bus 104. This allows the SPU 101 to read data from a test loaded by the microprocessor 211. The trigger circuit also has wrapper 102 via the test bus 104 into the buffer memory 218 an address counter 822 which is designed to overflow at the 10 and then send said data out to the diagnostic console 103. highest memory address of the buffer memory 218. At that Typically, a separate program executed on the diagnostic point the start address is reloaded with the beginning address console 103 displays this information in a human readable of the high memory space which is reserved for the buffer format as may be appropriate for the given application. 218. This converts a random access memory into a FIFO Programs executed by the SPU 101 can also read data from register. The stop counter 821 decrements when a latched 15 the diagnostics console 103 via the SIO interface 210 or TAP trigger signal line 824 becomes set. Subsequently the analysis interface 217, as shown in FIG. 2b, and write data out to engine 215 collects data into the buffer memory 218 from the individual scan flip-flops on the test wrappers 102 via the test variable FIFOs 804 for as many cycles as defined by the value bus 104. Significant processing, for example, expansion, loaded into the stop counter 821. The system IC designer uses compaction, or intermediate storage of data can be done by the buffer memory size and the value in the stop counter 821 20 the SPU 101 utilizing the buffer memory 218. In other as two parameters to control the amount of data collected embodiments, control functions may be supplied directly before and after an event has been detected. from the TAP interface 217 or SIO interface 210 to the analy- Also part of the trigger logic is a circuit which generates the sis engine 215 or BIST engine 212, via the processor bus 219 triggering signals on the trigger signal line 824. As shown in without involving the microprocessor 211. The SPU 101 may FIG. 9d, the generating circuit is structured to form Boolean 25 be coupled to either the system bus 205, or a separate test bus AND-OR logic 831 out of individually selectable terms 832. 104, or both. The coupling to the diagnostics console 103 may The terms 832 are fed from a polarity programming logic be via the TAP interface 217 or the SIO interface 210. The test circuit 833 that accepts individual trigger variables, Probe 1 bus 104 may be coupled to one or more test wrappers 102. through Probe N. In addition, the true or the complemented Another embodiment of the invention is defined in which value for the output function can be selected through a final 30 the SPU 101 does not include an embedded microprocessor level circuit 830. In one embodiment (shown in FIG.9d), the 211. In this case, the analysis engine 215 and the BIST engine result is also shifted into three successive flip-flops 834. Each 212 can access the buffer memory 218 and system bus inter- of the flip-flops 834 drives one input of each of a plurality of face 214 directly, following instructions received from the multiplexers 835. The other inputs of the multiplexers 835 are external diagnostics console 103. In this case, the loading of set to a logic one (1) level. Each multiplexer 835 is individu- 35 the configuration information and transfer of data to and from ally controlled through programmable bits and the multi- the analysis engine 215 is controlled using hardv plexer outputs are logically ANDed together to form a signal, signals. In this embodiment, the analysis engine 215 is imple- T[i], which represents the presence of the trigger condition mented in the form of an on-chip logic analyzer (OLA) which ods. The output from the captures sequential snapshots of sets of signals. The selected AND gate 836 is passed to an AND gate 837 with inputs from 40 signals form the digital probes 202. The selections are the corresponding AND gates 836 of duplicate circuits that achieved by coupling the signals for digital probes 202 to the produce T[0], T[1], through T[n] signals. The output of AND channels of the analysis engine 215 and turning-on enabling gate 837 is stored in a latch 838 to form the latched trigger circuits, if provided, to allow the signals on the digital probes signal on the line 824. Once the signal is set, the latched 202 value to be captured onto channels of the logic analyzer trigger signal maintains its value until it is reset through 45 215. As shown in FIG. 11, the channels of the logic ar nalyzer reprogramming by the microprocessor 211. In other embodi 215 are formed from probe storage elements (PSE) 1000 to ments, there may be more or fewer latches, and additional form a distributed serial shift register which acts as a pipeline logic to make adjustments to the phases (i.e., the relative to move data captured at a probe point towards the end of the clock cycle when signal is received) of the individual signals. logic analyzer channel where the data are stored in buffer Another embodiment of the trigger logic is shown in FIG. 50 memory 218. Each channel of the analysis engine 215 con- 10. This embodiment provides for the capability of reversing tains zero or more number of PSEs 1000 which are clocked by the data capturing function of the analysis engine 215 from a common periodic clock signal labeled "Cf" on a clock continually capturing new data until the trigger is detected, to signal line 1001. The clock signal is chosen (at design time) not capturing any data until a trigger is received. In the latter from among the fastest frequency of clock signals which are case, each time a trigger signal on the line 824 is received, the 55 used in generating source signals to be captured by the analysis engine 215 captures new data for a preprogrammed probes. This way all signals captured on the analysis engine number of cycles and then stops until the next latched signal 215 channels arrive at the end of the channels after a fixed, on the line 824 is received. To enable this mode of operation, predetermined number of clock cycles so that their cycle the trigger circuit shown in FIG. 10 causes the previous trig relationship to one another is preserved, regardless of the ger condition to be cleared so that it may be recognized again. 60 length (i.e., number of bits) of the individual channels of This mode is very useful since it enables the capture of signals analysis engine 215. around (i.e., before and after) multiple occurrences of trigger Subsequently, after the captured data has been transported conditions. The buffer memory 218 is utilized more effi- to the external diagnostics console 103, software processes ciently as the storage of unwanted cycles of data between the use the number of PSEs 1000 on each channel of the analysis trigger points is not required. It is also possible to program the 65 engine 215 to align the data with respect to one another. The trigger logic so it uses an externally generated trigger condi lengths (i.e. number of bits) of the serial shift registers on the tion 902 in place of an internally programmed event. individual channels of the analysis engine 215 are determined 2 US 8,996,938 B2 Page 2 Related U.S. Application Data continuation of application No. 11/261,762, filed on Oct. 31, 2005, now Pat. No. 7,080,301, which is a continuation of application No. 10/767,265, filed on Jan. 30, 2004, now Pat. No. 6,964,001, which is a continuation of application No. 09/275,726, filed on Mar. 24, 1999, now Pat. No. 6,687,865. Provisional application No. 60/079,316, filed on Mar. 25, 1998. (60) (51) Int. CI. 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PowerPC 604 RISC Microprocessor User's Manual, IBM Microelec- tronics, PowerPC, Motorola, 1994. * cited by examiner 2 14 US 8,996,938 B2 13 at design time so that signal delays due to physical distances Once enabled, the analysis engine 215 captures new values among the PSEs 1000 are sufficiently short to allow data to be first into the flip-flops along the OLA channels and subse- shifted between consecutive bits of the shift registers in a quently into the buffer memory 218 using trigger signals that single clock cycle. If necessary, the number of stages of the have been pre-programmed and implemented as shown in shift registers may be increased to satisfy this condition. Each 5 FIGS. 9c, 9d and 10. channel of the analysis engine 215 is coupled to a different In one mode of operation of the IC 100 shown in FIG. 16, data input port of the buffer memory 218. The collective data the human engineer may use the diagnostics console 103 to applied to the ports of the buffer memory 218 is written to an initialize both of the system logic and the SPU 101. In this address in memory which is identified by a common address manner, the SPU 101 may be programmed to perform logic register 822 that advances under control of the periodic clock 10 analyzer functions and specific probe points may be enabled so that a history of data values appearing at the selected probe signal "C" on the line 1001. points can be captured by SPU 101. Additionally, the trigger FIG. 12 shows a preferred embodiment of a channel of the logic shown in FIGS. 9 and 10 may be programmed to select OLA 215 which uses multiplexed PSEs 1000 to combine the a desired trigger event in order to stop the data capture opera- selection of probe points and pipelining captured data into a 15 to 15 tions. Next, the diagnostics console 103 invoke the IC 100 to single, efficient design. This enables the coupling one PSE execute its normal system operations. If and when the 1000 to two probe points or another PSE 1000. Scan opera- selected trigger event is detected and the analysis engine 215 tions shift a control signal into the PSE 1000 to program itself has captured the required data, the diagnostics console 103 to select one or the other of its input ports. instructs the SPU 101 to transfer the captured data values out The details of a multiplexed PSE are shown in FIG. 13. The 20 of the IC 100 and into the diagnostics console 103 where the PSE 1000, illustrated by a dotted line, is connected to a data may be formatted and presented for analysis and inter- multiplexer 1108 which has two input terminals connected to pretation. The diagnostics console 103 and the SPU 101 can two input probe paths, P1 and P2, for the logic analyzer constrain some of the signals on one or more test wrappers channels. Besides the probe clock signal line 1001, which 102 in order to affect the behavior of the IC 100 and perform carries the Cf signal, the PSE 1000 is connected to a first scan 25 logic analysis under these conditions. For example, this clock signal line 1101, which carries an A_clk signal, a sec- approach may be useful to determine how the overall behav- ond scan clock signal line 1102, which carries a B_clk signal, ior of the IC 100 is affected when some of the functionality of and a scan control line 1103, which carries a Scan_mode any one of the blocks 106 is disabled. signal. The PSE 1000 has three latches 1105, 1106 and 1107. In a different mode of operation automatic test equipment The output terminal of the latch 1105 is connected to one 30 (ATE) may access the IC 100 through its TAP interface 217 in input terminal of the latch 1106 and to one input terminal of order to initialize the SPU 101 so that internal scan strings 403 the latch 1107. One input terminal of the latch 1105 is con- and test wrappers 102 are loaded with predetermined test nected to the output terminal of the multiplexer 1108 and a values. The response of the blocks 106 is observed using the second input terminal of the latch 1105 forms a scan data scan strings 403 and test wrappers 102. Furthermore, the ATE input terminal 1104, SI. The output terminal of the latch 1107 35 may be programmed to instruct the SPU 101 to execute BIST forms a scan data output terminal, SO, and is also connected or other buffer memory 218 test functions and to check the to the control terminal of the multiplexer 1108. The output results to determine pass or fail conditions. terminal of the latch 1106 forms an output probe path, Q, for In yet another mode of operation, it is possible to use an the logic analyzer channels. in-circuit test (ICT) or similar board-level test equipment to The scan clock signals, A_clk and B_clk respectively, and 40 access the IC 100 through its TAP interface 217 in order to the Scan_mode signal configure the PSE 1000. For serial shift instruct the SPU 101 to turn-on its external memory test operations, the serial input (SI) on the line 1104 is captured function. In this mode, patterns are generated by the SPU 101 into the latch 1105 when the A_clk signal is applied and the and made to appear at specific I/O pins of the IC 100 which are output of the latch 1105 is captured into the latch 1106 when coupled to external memory. For example, the IC 100 may the B_clk signal is applied. If the Scan_mode signal on the 45 generate the data and address values that are applied to the line 1103 is set to a logic 1, the B_clk signal on the line 1102 external memory. The data responses received are captured in is also passed through a multiplexer 1109 and an AND gate order to determine if the external memory is functioning 1112 to the latch 1107 by a clock signal line 1111. Thus, correctly. non-overlapping A_clk and B_clk signals on the clock signal While the description above provides a full and complete lines 1101 and 1102 respectively clock serial shift operations 50 disclosure of the preferred embodiments of the present inven- in the PSE 1000. Signals scanned into the latch 1105 through tion, various modifications, alternate constructions, and line 1104 are also scanned into the latch 1107 and the latch equivalents will be obvious to those with skill in the art. Thus, 1106) and the SO output terminal. This completes the pro the scope of the present invention is limited solely by the gramming of the PSE 1000 such that value that has been metes and bounds of the appended claims. loaded into the latch 1107 controls input multiplexer 1108 55 What is claimed is: which selects between two input ports 1109 and 1110. Once 1. An integrated circuit comprising: the PSE 1000 has been programmed, the Scan_mode signal one or more logic blocks configured to generate one or on control line 1103 signal is set to and maintained at logic 0 more system operation signals at one or more system until the PSE 1000 is programmed with a new value. When operation clock rates; the Scan_mode signal is set to logic 0, the PSE 1000 performs 60 a service processor unit configured to perform one or more its normal data capture function using the clock signal Cf on debug operations on one or more of the logic blocks, the the line 1001. The Cf clock signals are passed by the multi- service processor unit comprising: plexer 1109 to the latch 1106 by a clock signal 1110. The latch a control unit configured to control the service processor 1106 captures the signals from the latch 1105 and the multi- unit; plexer 1108 at the Cf clock rate and passes the signals out to 65 a memory; the Qoutput terminal. The multiplexed-PSEs shown in FIGS. an analysis engine; and 12 and 13 build cost efficient logic analyzer channels. a bus interface; and 2 US 8,996,938 B2 15 16 a multiplicity of probe lines configured to capture and propagate one or more of the one or more system opera- tion signals from the logic blocks to the service proces- sor unit. 2. The integrated circuit of claim 1, wherein the analysis 5 engine is configured to align signals received from the probe 14. The integrated circuit of claim 1, further comprising: a test access port controller. 15. An integrated circuit comprising: a multiplicity of logic blocks configured to generate one or more system operation signals; a logic analyzer coupled to at least one external interface; lines. and 3. The integrated circuit of claim 1, wherein the analysis a multiplicity of probe lines configured to propagate sig- engine includes a variable first-in, first-out (FIFO) element. nals to the logic analyzer, wherein at least one of the 4. The integrated circuit of claim 1, wherein the analysis 10 probe lines is configured to propagate at least one of the engine is configured to store aligned signals in buffer system operation signals, and wherein the logic analyzer memory. 5. The integrated circuit of claim 1, wherein the service is configured to: processor unit further comprises a parallel I/O port, wherein store a selected set of the system operation signals for retrieval through the at least one external interface; data and instructions are sent through the parallel I/O port to 15 and the service processor unit from an external console, and align the selected set of system operation signals. wherein result data is provided through the parallel I/O port to the external console. 16. The integrated circuit of claim 15, wherein the logic 6. The integrated circuit of claim 1, wherein the service analyzer includes a variable first-in, first-out (FIFO) element. processor unit further comprises a serial I/O port, wherein 20 17. The integrated circuit of claim 15, wherein at least one data and instructions are sent through the serial I/O port to the of the probe lines is configured to propagate at least one signal service processor unit from an external console, and wherein representing at least one analog event. result data is provided through the serial I/O port to the 18. The integrated circuit of claim 17, wherein the at least external console. one analog event comprises a ground bounce event. 7. The integrated circuit of claim 1, wherein the service 25 19. The integrated circuit of claim 15, further comprising processor unit further comprises a JTAG port, wherein data an analog-event detection circuit, wherein at least one of the and instructions are sent through the JTAG port to the service probe lines is configured to propagate one or more signals from the analog-event detection circuit. processor unit from an external console, and wherein result 20. The integrated circuit of claim 19, wherein the analog- data is provided through the JTAG port to the external con- sole. event detection circuit is configured to detect a voltage level. 8. The integrated circuit of claim 1, wherein the multiplic- 21. The integrated circuit of claim 15, wherein the multi- plicity of probe lines includes at least one digital probe line. ity of probe lines includes at least one analog probe line. 9. The integrated circuit of claim 1, wherein the multiplic- 22. An integrated circuit comprising: ity of probe lines includes at least one digital probe line. one or more logic blocks configured to generate one or 10. The integrated circuit of claim 9, wherein the digital 35 more system operation signals at one or more system probe line comprises at least one storage element and is operation clock rates; a service processor unit configured to perform one or more configured to move one or more of the system operation debug operations on one or more of the logic blocks, the signals from one or more of the logic blocks to the service service processor unit comprising: processor unit via the bus interface. 11. The integrated circuit of claim 10, wherein the at least 40 a control unit; a memory; one storage element is configured to use a system clock to move the one or more of the system operation signals. an analysis engine; and 12. The integrated circuit of claim 1, wherein the control a bus interface; and unit is configured to execute instructions for providing test a multiplicity of probe lines configured to capture one or signals to one or more of the logic blocks and for retrieving 45 more of the one or more system operation signals from one or more test signal results from one or more of the logic the logic blocks to the service processor unit, wherein blocks. the analysis engine is configured to align signals 13. The integrated circuit of claim 1, wherein the bus inter- received from the probe lines. face is a test bus interface. U.S. Patent System IC 100 WOLOOGARARAAAAAALAALAAL 3rd-Party Core YA00000000000000000000 Mar. 31, 2015 2000cc దానంతరoodnooloodenobandicoot కారణంగeo dowతందం UW yosscode odcobobododododbobobodododo.bocco WoWATAKUSALITAS 00000 Bissoluteriare Poloko toon0000000000000000000000000000000 1 Host Processor OOOOOOOOOOOOOOOOOOO System Bus 2 105 తరతరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరరర000 User-Developed Core Sheet 1 of 20 OX989 occeSME S rrrrrrrr **USANAERAT. ** ...Peripheral.Bus... reprivrrEVY Figure la (prior art) US 8,996,938 B2 2 U.S. Patent Mar. 31, 2015 Sheet 2 of 20 US 8,996,938 B2 103 104 m BES 101 100 / 105 sur ווווווווווווויטי KIOMINANONOOMIA System Bus 102 106 User-Developed Core ADALAHADHAPA HARKKAFARA IIIIIIIIIIIIII Peripheral Bus FIG. 1b - 106 RARNIR SUMUT. 100 3rd-Party Core Bridge PROXWWW GUS Bus Interface Block IIIIIIIIIIIIIII System IC 102 BMW 102- Host Processor SPU 101 222 215 211 212 U.S. Patent 210 SIO Scan Control Analysis Engine Micro- processor BIST engine 217 Parallel 1/0 TAP 216 Range Check Interrupt Handler Test Bus Interface Buffer Memory Test Bus Interface Mar. 31, 2015 d 220 213 218 214 - MI -- - - - - - - - - - - - 221 4-4 203 204 Trigger PILI 2 Test Bus 201 Analog Probes Sheet 3 of 20 System Bus 104. 105 202 Scan string 2 403 Digital Probes Core Block Test Wrapper 106 102 US 8,996,938 B2 FIG. 2 2 U.S. Patent Mar. 31, 2015 Sheet 4 of 20 US 8,996,938 B2 101 213 SPU Test bus Interface 000999000000000000000 probe string - 402 COPRU coor KAAAAAAAAA 403 Scan string UUUUUUURRRRRRRRRRRFARE Core block 106 401 అదరగరరకరరరరరు 102 Test wrapper Figure 3a 401 Test bus connector Trigger 401 204 Test bus 104 U.S. Patent Test wrapper 102 426 4211 401 Test bus 104 Test bus 104 Tu Test hus 104 ban come 104 Test wrapper 102 404 ------,427 t u Test bus 104 S -425 Mar. 31, 2015 jorter recensione Test bus 104 SPU 101 Test bus 2 SPU 101 Sheet 5 of 20 Figure 3b Preferred Embodiment of Test Bus Connector oppos bood yoool Sooded book 000 pool US 8,996,938 B2 Probe String 402 401 U.S. Patent - - - - - - - -- - - - - - - - - - - - - - - - - - - - Trigger 204 Trigger 401 Test Bus 104 Test Bus 104 Mar. 31, 2015 40107 401 Test wrapper 102 - - - - - - - - - - - 2 O D e core block P Sheet 6 of 20 401D Core block - - - - - - - - - - - - - - - - - - - Scan string 403-4 106 401 - - - - - - - - - - - - - - - Connecting Probe String, Test Wrapper or Scan String to Test Bus FIG. 30 US 8,996,938 B2