KR101116956B1 - System on Chip capable of Testing based on Test Access Mechanism - Google Patents

Abstract

The present invention discloses a system on a chip capable of TAM based testing and a test method thereof. The present invention provides a system on a chip including a plurality of cores, comprising: a plurality of sub-TAMs (test access mechanisms) connected to at least one core and receiving test data from outside the chip and transferring the test data to the connected cores; M (m is two or more natural numbers) scan control signal lines provided independently for each of the plurality of sub-TAMs; And a scan control signal generation module for applying an m-bit scan control signal to the scan control signal line. According to the present invention, there is an advantage that can shorten the overall test time in the parallel core scan test.

TAM, Scan Control Signal, Parallel Core, SoC, Dedicated, Core Selector

Description

System-on-chip capable of TAM-based testing and test method thereof System on Chip capable of Testing based on Test Access Mechanism

The present invention relates to a system-on-chip capable of TAM-based testing and a test method thereof, and more particularly, to a system-on-chip and a test method thereof that can shorten the test time for a plurality of cores.

Various digital information devices such as mobile phones, PDAs, digital TVs, and smart phones require many semiconductor chips such as microprocessors, network chips, and memories in order to implement Internet access and computing functions smoothly. In addition, with the trend toward more and more complex diversification, convergence between components of information equipment is expected to be further developed. Therefore, more semiconductor chips will be needed in information equipment.

By integrating various components into one semiconductor chip, System on Chip (SoC) technology has emerged as a technology for one-chip not only semiconductor but also individual components in the future. SoCs integrate microprocessors, digital signal processors (DSPs), memory, and baseband chips into a single chip, allowing the chip to function as a system. For example, Intel's recently announced GSM / GPRS integrated chip solution combines a baseband chip, a DSP, a microprocessor to drive applications, and flash memory. The integrated chip solution offers features such as reduced cost, reduced size and extended battery life compared to the configuration of individual chips.

Due to these advantages, SoC is expected to be further adopted in various digital devices due to a great demand in the future, such as mobile phones, PDAs, portable media terminals, and home network servers.

Advances in semiconductor processing have made it possible to produce high quality IP cores, but more and more time is required to test these cores inside the SoC. As a result, expensive test costs are incurred.

This is because the ultra-fine process places more emphasis on noise, signal delay, and interference, making traditional failure models and associated test pattern generation tools inadequate.

Inadequate communication of information for testing between IP user layers makes the SoC difficult to test. In addition, the difficulty in testing the SoC is that it is not easy to obtain a contact point necessary for testing the input and output of the chip to the input and output of the core. If several cores are embedded in a chip, it is impossible to assign a test pin to each core. Therefore, the control and observation necessary for the test on cores present in each part of the chip with a minimum number of pins can be effectively made.

In order to perform SoC tests, a core test wrapper and a test access mechanism (TAM) are required inside the SoC. The core test wrapper acts as an interface between the core inside the SoC and the TAM. The TAM takes test data from the outside of the chip and delivers it to the core test wrapper.

Meanwhile, in the conventional TAM-based test, there are a serial test and a parallel core scan test method.

In the case of the sequential test, as shown in FIG. 1, all TAMs are allocated to the core to be tested regardless of core characteristics inside the SoC, and the test for the plurality of cores A to E is performed sequentially.

In this sequential test, each core uses a larger TAM width than necessary, causing waste of TAM, and the test time is long because the test of the next core proceeds after the test for one core is finished. There is a problem.

To solve this problem, a parallel core scan test method is proposed.

As shown in FIG. 2, in the case of the parallel core scan test, unlike the sequential test, an appropriate TAM width is allocated to each core by scheduling results by optimizing the test structure, that is, dividing the entire TAM into a plurality of sub-TAMs. Therefore, TAM can be used efficiently.

In general, each core is shifted in by the number of flip-flops, and the scan control signal must be dropped to zero for update and capture, and thus, other cores in the shift must be stopped. After this again the scan control signal changes to 1 and the updated value is shifted out.

According to the conventional parallel core scan test method, since a plurality of sub-TAMs share one scan control signal line (Scan Enable), even if the parallel core scan test is performed, as described above, when the update and capture are performed on a specific core A test stop is made for the other cores in the test.

Therefore, in the conventional parallel core scan test method, the test stop is performed by the number of cores multiplied by the number of test patterns of each core and the number of change of cores during the entire SoC test process due to the update and capture.

In recent years, when a large number of cores are disposed in the SoC, when the frequent test stops are required as described above, the entire test time becomes considerably longer.

The present invention, in order to solve the problems of the prior art as described above, proposes a system-on-chip capable of TAM-based testing and its test method that can reduce the test time.

In order to achieve the above object, according to a preferred embodiment of the present invention, in a system on a chip including a plurality of cores, is connected to at least one core, receives test data from the outside of the chip to the connected core Delivering a plurality of sub-TAMs (Test Access Mechanism); M (m is two or more natural numbers) scan control signal lines provided independently for each of the plurality of sub-TAMs; And a scan control signal generation module for applying an m-bit scan control signal to the scan control signal line.

According to another aspect of the present invention, a system on a chip comprising a plurality of cores, comprising: a plurality of sub-TAMs connected to at least one core and receiving test data from outside the chip and transferring the test data to the connected cores; A scan control signal line shared by the plurality of sub-TAMs; A scan control signal generation module for applying a scan control signal to the scan control signal line; And a core selector for outputting a core select signal for informing a core to be simultaneously tested by the plurality of sub-TAMs, wherein the core selector receives a core address signal from an address bus connected to a TIC module to select control. And an address decoder for outputting a signal, wherein the address decoder is provided with a system on chip for outputting a high signal when an address of a core to be tested is changed.

According to another aspect of the present invention, a system on a chip connected to a plurality of cores and at least one core and including a plurality of sub-TAMs (Test Access Mechanism) for receiving test data from outside the chip and transferring the test data to the connected cores. A method for parallel core scan testing, comprising: providing m (m is a natural number of two or more) scan control signal lines provided independently for each of the plurality of sub-TAMs; Generating a scan control signal of m bits (where m is a natural number of two or more) using an external function input pin; And applying each of the m-bit scan control signals to at least one core connected to each sub-TAM through separate scan control signal lines.

According to the present invention, by using a dedicated scan control signal for each sub-TAM partitioned by test structure optimization scheduling, there is an advantage in that cores connected to various sub-TAMs in the SoC can be independently tested.

In addition, according to the present invention, there is an advantage that the total test time of the SoC can be shortened by preventing the core connected to another sub-TAM from being affected by the test stop of the core connected to each sub-TAM through a dedicated scan control signal.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate a thorough understanding of the present invention, the same reference numerals are used for the same means regardless of the number of the drawings.

3 is a diagram illustrating a test structure according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the SoC according to the present invention includes a plurality of cores and a plurality of sub-TAMs for testing the cores.

The test with a plurality of sub-TAM and scan control signals is defined below as a parallel core scan test in that a plurality of cores are tested at the same time by the plurality of sub-TAM.

Each sub-TAM (Test Access Mechanism) is used as a transmission path for test data, and is connected to at least one core, and receives test data from outside the chip and transfers the test data to the connected core.

3 shows five cores A through E, the first sub-TAM (Sub-TAM1) to Core C and Core D, the second sub-TAM (Sub-TAM2) to Core B and Core E And a third sub-TAM (Sub-TAM3) is connected to Core A, and the TAM width is 17 bits in the first sub-TAM, 9 bits in the second sub-TAM, and 6 bits in the third sub-TAM, respectively. The assignment is shown as an example.

In the following description, the present invention will be mainly described based on the provision of three sub-TAM. However, it will be apparent to those skilled in the art that various sub-TAMs can be provided for convenience of description only.

Here, the number of sub-TAMs and sub-TAM widths for testing a plurality of cores included in the SoC may be determined according to various test scheduling, and the number of scan chains, the maximum scan chain length, the number of input / output pins / type of each core And the number of test patterns.

According to one preferred embodiment of the present invention, dedicated scan control signal lines are provided for the plurality of sub-TAMs.

In the test of each core, shift, update, and capture processes are performed by being connected to the scan chain of each core according to a scan control signal, that is, a scan enable signal.

3, three dedicated scan control signal lines SE1 to SE3 are shown as three sub-TAMs are provided.

According to the present invention, cores connected to each sub-TAM with independent dedicated scan control signal lines SE1, SE2, and SE3 for each sub-TAM use a shared structure. Accordingly, since the scan control for the core on one sub-TAM does not stop the test of the core that is performing the test in another sub-TAM, the overall test time can be shortened.

4 is a view for explaining the test time reduction effect in the parallel core scan test method and the conventional parallel core scan test method according to the present invention.

4 shows an example where a single test pattern is applied for each core, and shows the test down time for Core A where the longest test time is required.

As shown in FIG. 4A, when a single scan control signal line is used as in the prior art, five test stops occur for update and capture of data for five cores, and when the core to be tested is changed, For example, when a change is made from core C connected to a first sub-TAM to core D, and a change from core B connected to a second sub-TAM to core E, a test stop occurs, respectively, to provide the longest test time. A total of seven test stops are made for core A with it.

However, as shown in FIG. 4B, when providing a dedicated scan control signal line for each sub-TAM, when looking around the core A, only one test stop is made for update and capture inside the core. Required.

As described above, since the test stop on the remaining cores or the change of the cores is not stopped during the core A test, the total SoC test time can be shortened according to the present invention.

Meanwhile, a separate external pin is not required for a scan control signal provided independently for each sub-TAM according to the present invention, and a function input pin included in an existing SoC is used.

5 is a diagram illustrating a structure of a scan control signal generation module according to the present invention, and FIG. 5 illustrates a scan control signal generation module in a standard AMBA (Advanced Microcontroller Bus Architecture).

As shown in FIG. 5, the scan control signal generation module according to the present invention uses a functional input pin (Functional Input) which is not used in a test, as a scan control signal.

The scan control signal generation module according to the present invention selects a mux 502 which selects one of a control signal and a scan control signal of the test interface controller (TIC) module 500 in the scan test mode. Include. The mux 502 applies one of the control signal and the scan control signal to the core through the scan control signal line through a scan test mode signal according to a control signal of a wrapper instruction register (WIR) decoder.

According to the present invention, the scan control signal generation module generates a scan control signal of m bits (where m is a natural number of 2 or more), and m may be 3 when three scan control signal lines are provided as shown in FIG. 3.

On the other hand, the SoC according to the present invention is provided with a core selector (Core Selector) for generating a core select signal for indicating that the test target to the core to be tested at the same time.

6 is a view showing the configuration of the core selector according to the present invention, Figure 6 is also a diagram showing the core selector structure in the standard AMBA.

As shown in FIG. 6, a core selector in accordance with the present invention includes a test mode core selector 608 (hereinafter, referred to as “description”) including an address decoder 600, one or more logic gates 602, 604, and a register 606. TMCS ') and the mux 610.

The address decoder 600 receives address information on a core currently being tested from an address bus (HADDR: AMBA address bus) connected to the TIC module 500, and selects a core to the TMCS 608 according to the received address information. The control signal EN_TMCS is applied.

According to the present invention, the address decoder 600 may output the core select control signal as the high signal 1 only when the received address information is different from before, that is, when the core to be tested is changed.

An AND (logical) gate 602 is disposed on the address decoder output side of the TMCS 608, and the AND gate 602 is high only when the core address is changed through a logical product of the clock signal HCLK and the core select control signal. Apply a signal.

On the other hand, the register 604 of the TMCS 608 has the number of bits (Cn) corresponding to the number of cores, and updates the register information when a high signal is applied from the AND gate 602.

Here, the register information is information for identifying a core currently being tested.

In this case, the update of the register information may include at least a part of the core select control signal of the address decoder 600 and the bit 32 applied through the write data bus HWDATA connected to the TIC module 500 (Cn bit). ) Can be achieved.

For example, when five cores are included in the SoC as shown in FIG. 3, the register 604 may be configured with 5 bits. For the cores A to E of FIG. 4B, 11100 at t1, 11010 at t2, It may be updated to 10011 at time t3.

When the register information is updated according to the change of the core as described above, the mux 610 applies the core select signal HSELx to the core side according to the signal through the OR gate 606 inside the TMCS 608.

7 is a diagram illustrating an overall control structure for parallel core scan test on AMBA based SoC according to the present invention.

The TIC module 500 according to the present invention uses a TIC module proposed by ARM in order to facilitate test path separation.

In addition, a scan test mode (ScanTestMode) pin 700 is added to distinguish the functional test from the scan test.

Here, a function test is performed when "0" is applied to the scan test mode pin 700, and a scan test mode for performing a scan test when "1" is applied to the scan test mode pin 700 is performed. Shall be performed.

Hereinafter, the operation of the respective components in the function test mode in which "0" is applied to the scan test mode pin 700 will be described, and then, if "1" is applied to the scan test mode pin 700. The operation of the respective components in the scan test mode will be described.

First, in the function test mode execution state, the TIC module 500 transmits the address and data received through the TBUS to the test target core (not shown) through the HADDR and HWDATA of the AHB, and scans from the test target core. To read the output, a TicRead signal is generated and applied to the OR gate 702.

The external bus interface (EBI) module 706 reads HRDATA from the core under test according to the TicRead signal applied through the OR gate 702 and outputs a test result through the TBUS.

On the other hand, in the function test mode execution state, when "1" is applied to the scan test mode (ScanTestMode) pin 700 is switched to the scan test mode execution state.

After switching to the scan test mode execution state, the TIC module 500 receives scan input data from the outside through the TBUS and transmits the data to the test target core, and generates a TicRead signal to provide the OR gate 702.

The OR gate 702 provides a TicRead signal to the EBI module 706 through an OR logic operation when a TicRead signal provided from the TIC module 500 is input while “1” is applied through the scan test mode pin 700. do.

The EBI module 706 receives the scan output data from the test target core through the HRDATA of the AHB according to the TicRead signal provided from the OR gate 702 and provides the output data EBIDATAOUT and the output address EBIADDROUT to the mux 704. do.

The mux 704 sends the scan output value of the output data EBIDATAOUT to EBIEXTADDROUT when "1" is applied through the scan test mode pin 700, that is, in the scan test mode, while "0" is The output address (EBIADDROUT) is transmitted to EBIEXTADDROUT in the authorized state, that is, in the functional test mode.

As noted, the TIC module 500 and the EBI module 706 use the OR gate 702 and the MUX 704 to scan scan mode (i.e., scan test mode pin 700) to " When 1 "is applied, the path of HRDATA-> output data (EBIDATAOUT)-> external output address (EBIEXTADDROUT), which are data output from the core under test, is maintained.

As a result, it can be seen that the TIC module 500 is used as a test input path and the EBI module 706 is used only as a test output path.

Therefore, since the scan output is automatically performed when the scan input is performed, parallel processing of the scan input and the scan output is possible without a read transaction for the scan output.

In addition, as shown in FIG. 7, the TIC module 500 used for the functional test of the AMBA bus is reused for the core select signal, thus eliminating the need for additional logic for parallel core scan test.

Hereinafter, the test time reduction effect in the test method according to the present invention will be described.

In the case of using a single scan control signal in the parallel core scan test, the test time increases compared to the case in which a dedicated scan control signal is used for each sub-TAM.

[Table 1] Comparison of parallel core scan test time by using single scan control signal and independent scan control signal for each sub-TAM

SoC Dedicated SE by TAM Use a single SE Test increase time comparison
SE number
Forest time
2cycle stop 2cycle stop Increase time Increase d695 3 21518 23054 1536 7.14 p22810 6 222471 265375 42904 19.29 p34392 4 551778 681312 129534 23.48 p93791 3 915095 956265 41170 4.50 u226 4 10665 17769 7104 66.61 d281 4 4084 4740 656 16.06 h953 3 119357 120847 1490 1.25 g1023 5 16855 21095 4240 25.16 f2126 3 335334 336602 1268 0.38 q12710 4 2222349 2226503 4154 0.19 t512505 3 5268868 5283344 14476 0.27 a586710 3 22475033 26725361 4250328 18.91

For comparison of test times, see ITC'02 Benchmark Circuit (E.J. Marinissen, V. Iyerngar, and K. Charkrabarty, ITC'02 SOC Test Benchmarks.,

The total TAM width is assumed to be 32 bits for http://itc02socbenchm.pratt.duke.edu/), based on the information of the cores to be tested and the available TAM width on the SoC, the number of sub-TAMs, sub-TAM Existing TR-ARCHITECT (Min Pil Jae, Jae Hoon Song, Hyun Bin Lee, and Sung Joo Park, “Design of Access Mechanism for AMBA-based SoC Tests”), The Korean Institute of Electronics Engineers, Vol.43, No.10, Oct. 2006.), and based on the results, parallel core scan test time is divided into a structure using a dedicated scan control signal for each sub-TAM and a structure sharing a single scan control signal. Obtained.

In this case, when using a single scan control signal, it is assumed that the clock cycle required to stop a core test that does not perform core scan capture is 2. The number of SE in Table 1 is determined according to the result of applying TR-ARCHITECT on the target SoC. If a dedicated scan control signal is used for each sub-TAM, the minimum test time is obtained because there is no influence between cores on different sub-TAMs being tested at the same time. On the other hand, when a single scan control signal is used, the test time of one core affects the core test on the other sub-TAM being tested at the same time, and thus the test time increases as shown in [Table 1].

As an application example of the present invention, a method using an sequential test of an existing AMBA-based SoC to construct an AMBA-based SoC and to examine the test time reduction effect when performing a parallel core scan test using the parallel core scan test design technique of the AMBA-based SoC And analyzed.

The test subjects consisted of the ITC'02 test benchmark circuit, which was divided into sequential test and parallel core scan test by varying the bus width Wmax from 16 to 64. Sequential tests use the AMBA bus as the TAM and test the cores under test one by one, allocating all of the given TAM widths.

In the case of parallel core scan test cores, the TAM chain segmentation process is included in the test scheduling process. Therefore, the TAM chain segmentation is performed on the target cores of the sequential test for fair comparison.

The test time of the parallel core test design technique is obtained by applying the modified TR-ARCHITECT.

Tables 2 and 3 compare the sequential and parallel core scan test times for the ITC'02 test benchmark circuit.

[Table 2] Test time comparison for benchmark circuit (when scan chain is fixed)

SoC Wmax Sequential Test Parallel Core Test Reduction ratio (%)
d695 16 59291 44328 25.24 32 45161 21539 52.31 64 42462 11045 73.99
p22810 16 864474 458146 47.00 32 701254 222537 68.27 64 653768 133468 79.58
p34392 16 1916413 1010866 47.25 32 1769198 551823 68.81 64 1714304 544624 68.23
p93791 16 2141641 1791725 16.34 32 1412433 915182 35.21 64 807039 455813 43.52
u226 16 73224 18666 47.51 32 60879 10668 82.48 64 60651 8002 86.81
d281 16 19340 8182 57.69 32 14462 4093 71.70 64 12002 3938 67.19
h953 16 244495 119372 51.18 32 239877 119372 50.24 64 237722 119372 49.79
g1023 16 89839 34492 61.61 32 72010 16882 76.56 64 63556 14821 76.68
f2126 16 592732 372131 37.22 32 580014 335337 42.18 64 574072 335337 41.59
q12710 16 7261050 2222349 69.39 32 6755560 2222349 67.10 64 6501592 2222349 65.82
t512505 16 23189698 10531082 54.59 32 17754663 5268952 70.32 64 17651036 5228504 70.38
a586710 16 73608777 41523877 43.59 32 51338095 22475039 56.22 64 38247890 12510362 67.29

[Table 3] Comparison of test times for benchmark circuits (when scan chain is changeable)

SoC Wmax Sequential Test Parallel Core Test Reduction ratio (%)
d695 16 49105 42046 14.38 32 27288 21124 22.59 64 16371 10705 34.61
p22810 16 631976 431409 31.74 32 397737 219057 44.92 64 268453 110991 58.66
p34392 16 1105292 971867 12.07 32 743257 499134 32.85 64 581105 241296 58.48
p93791 16 2005507 1757689 12.36 32 1072815 885158 17.49 64 608300 444282 26.96
u226 16 70260 18669 73.43 32 59435 10671 82.05 64 57991 6852 88.18
d281 16 15474 8013 48.22 32 9660 4161 56.93 64 6846 2133 68.84
h953 16 81951 72509 11.52 32 44822 36389 18.81 64 25967 18432 29.02
g1023 16 59891 31620 48.20 32 36647 16299 55.52 64 25602 8349 67.39
f2126 16 338594 324702 4.10 32 172394 163107 5.39 64 89500 81924 8.46
q12710 16 2016262 1529906 24.12 32 1025922 766340 25.30 64 527880 384683 27.13
t512505 16 10991124 10253123 6.71 32 5542030 5132939 7.38 64 2819815 2573315 8.74
a586710 16 66461262 41886450 36.98 32 40727260 21058777 48.29 64 25905395 11486610 55.66

The unit of test time is clock cycle, and in order to find out more accurate reduction effect, the experiment was divided into the case where the change is impossible and the case where the change is possible because the scan chain of the core is fixed. The ITC'02 test benchmark circuit assumes that the scan chain of the core is fixed. However, because there is information about the number of flip-flops, it is possible to experiment even when the scan chain of the core can be changed. The results of Tables 2 and 3 show that the parallel bus width test time decreases as the bus width increases. For sequential tests, the total bus width is allocated regardless of the core characteristics, and the larger the bus width, the less efficient it is compared to the parallel core scan test method. Also, comparing [Table 2] and [Table 3], it can be seen that the test reduction effect is larger when the scan chain is fixed than when the scan chain can be changed. In general, since most cores are in hard IP form and the scan chain cannot be changed, it can be seen that the present invention can reduce test time more effectively.

Table 4 shows the results of comparing the test time and area with the conventional sequential test method based on the actual AMBA-based SoC circuit.

[Table 4] Characteristics of Test Cores

Cores Total area
(# NAND gates) # PI #
PO #
DFF # Test vector Fault Coverage (%) Original Full scan
AHB Leon3 processor 41901 46303 252 148 1166 386 99.75 SDRAM Controller 3701 4115 93 119 212 68 99.45 AHB-PCI Bridge 6364 7055 40 145 275 79 99.92 Ethernet MAC 32737 35580 109 243 1339 485 99.99
APB UART 9308 10523 69 32 524 231 98.99 GPIO 4922 5107 78 104 96 13 100 RTC 7566 9067 47 32 340 130 99.99

The structure of the AMBA-based system for the experiment is shown in FIG. 8 and the core characteristics of the SoC are shown in [Table 4]. Test vectors were generated using a commercial automated test pattern generation (ATPG) tool, and RTL codes were synthesized using a 0.25 μm process library. The third and fourth columns represent the area of each core in number of gates (based on NAND gates with two inputs). Columns 5, 6, and 7 are the numbers of PIs, POs, and D-flipflop, respectively, and information about the number of test vectors and fault coverage is listed in columns 8,9. The experiment was done in the same way as the test benchmark circuit, and the scan chain is free to change.

The experimental results are shown in [Table 5], and as in the previous case, as the total TAM width increases, the test time decrease rate is high.

[Table 5] Test time comparison of actual AMBA based SoC

SoC Wmax Sequential Test Parallel Core Test Reduction ratio (%)
Real SoC circuit 16 114406 99455 13.07 32 61467 50122 18.46 64 35236 25467 27.72

Testing with a parallel core scan test design reduces test time compared to traditional sequential test methods, but increases the area due to additional designs for parallel core scan test designs.

Since the sequential test method tests the core using a test harness instead of the standard wrapper, only the wrapper portion is first compared to [Table 6] for an objective area comparison.

Table 6 Comparison of test areas of real AMBA based SoCs

Cores Test harness area Standard wrapper area % Increase
AHB Leon3 processor 3975 4647.38 16.92 SDRAM Controller 2041 2642.04 29.45 AHB-PC IBridg 1891 2354.04 24.49 Ethernet MAC 3027 4135.38 36.62
APB UART 1271 1458.04 14.72 GPIO 1785 2322.04 30.09 RTC 988 1223.38 23.82 Total 14978 18782.3 25.40

The area is represented by the number of two input NAND gates. In the sequential test method used here, the test harness is not connected to the output of the core, whereas in the present invention, since the standard wrapper is connected to both the input and the output, the area of the standard wrapper is large. Except for the wrapper, 224 gates are increased when comparing the area with the sequential test method. Through this, it can be seen that the AMBA-based parallel core scan test design technology of the present invention can reduce the test time with a small area increase compared to the conventional method.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Additions should be considered to be within the scope of the following claims.

1 illustrates a TAM structure and test time for sequential testing according to the prior art.

2 illustrates a TAM structure for a parallel core scan test according to the prior art.

3 illustrates a test structure in accordance with one preferred embodiment of the present invention.

4 is a view for explaining the test time reduction effect in a parallel core scan test method and a conventional parallel core scan test method according to the present invention.

5 is a diagram illustrating the structure of a scan control signal generation module according to the present invention;

6 is a diagram showing the configuration of a core selector according to the present invention;

7 illustrates the overall control structure for parallel core scan test on AMBA based SoC in accordance with the present invention.

8 is a diagram illustrating a configuration of an AMBA-based system on chip to which the present invention is applied.

Claims (12)

In a system on a chip comprising a plurality of cores, A plurality of sub-TAMs connected to at least one core and receiving test data from outside the chip and transferring the test data to the connected cores; M (m is two or more natural numbers) scan control signal lines provided independently for each of the plurality of sub-TAMs; A scan control signal generation module for applying an m-bit scan control signal to the scan control signal line; And And a core selector for outputting a core select signal to indicate one or more cores being simultaneously tested by at least one of the plurality of sub-TAMs. The method of claim 1, One or more cores connected to a first sub-TAM share a first scan control signal line allocated for the first sub-TAM. The method of claim 1, And the scan control signal generation module generates the scan control signal using an external function input pin. delete The method of claim 1, The core selector includes an address decoder that receives a core address from an address bus of a TIC module and outputs a core select control signal. The method of claim 5, And the address decoder outputs a high signal when an address of a core to be tested is changed. The method of claim 5, And the core selector outputs the core select signal using at least some of the bits applied through the select control signal and a write data bus coupled to the TIC module. The method of claim 1, The plurality of sub-TAM, A TIC module which receives test data from a pin connected to the outside in a scan test mode, applies the test data to the core through a bus, and generates an output data read signal; A signal generation module configured to generate a scan output read signal using the scan test mode signal and the output data read signal inputted to perform the scan test mode; An EBI module configured to read and output scan output data from the core according to the scan output read signal; And And a mux for transmitting scan output data and an output address to the outside according to the scan test mode signal. delete delete delete A method for parallel core scan testing a system-on-chip comprising a plurality of sub-TAMs (Test Access Mechanism) connected to a plurality of cores and at least one core and receiving test data from outside the chip and transferring the test data to the connected cores. Providing m scan control signal lines (m is two or more natural numbers) provided independently for each of the plurality of sub-TAMs; Generating a scan control signal of m bits (where m is a natural number of two or more) using an external function input pin; Applying each of the m-bit scan control signals to at least one core connected to each sub-TAM via separate scan control signal lines; And And outputting a core select signal to indicate one or more cores to be tested simultaneously by at least one of the plurality of sub-TAMs.

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