CN101000367A - System chip test data compression method of block mark - Google Patents

Abstract

Translated fromChinese

一种块标记的系统芯片测试数据压缩方法，其特征是用0标记与参考数据块相容的整块待编码数据块，用10标记与参考数据块反相相容的整块待编码数据块，同时动态更新参考数据块来增加参考数据块与待编码数据块相容或反相相容的概率。本发明方法是一种非侵入式的测试数据压缩方法，无需改变被测试的电路结构，尤其是电路中扫描链的结构，用1位或2位数据标记整块数据，降低了所需测试数据的存储容量，缩短了测试应用时间。

A kind of system chip test data compression method of block mark, it is characterized in that with 0 mark and reference data block compatible whole block to be coded data block, with 10 mark and reference data block inversely compatible whole block to be coded data block , while dynamically updating the reference data block to increase the probability that the reference data block is compatible or inversely compatible with the data block to be encoded. The method of the present invention is a non-invasive test data compression method, without changing the structure of the circuit to be tested, especially the structure of the scan chain in the circuit, using 1-bit or 2-bit data to mark the entire block of data, reducing the required test data The storage capacity shortens the test application time.

Description

Translated fromChinese

一种块标记的系统芯片测试数据压缩方法A block-marked system chip test data compression method

技术领域technical field

本发明涉及集成电路测试技术，特别是对系统芯片(System-on-a-Chip，SoC)的外建自测试(Built-Out Self-Test，BOST)方法中测试数据压缩方法。The invention relates to an integrated circuit test technology, in particular to a test data compression method in a built-out self-test (Built-Out Self-Test, BOST) method for a system chip (System-on-a-Chip, SoC).

技术背景technical background

集成电路技术的发展使得可在一个芯片中集成数以亿计的器件，并且可以集成预先设计和经过验证的IP核，如存储器，微处理器，DSP等。这种多元化的集成芯片已经成为能处理各种信息的集成系统，被称为片上系统或系统芯片System-on-a-Chip，SoC。SoC大大降低了系统成本，缩短了设计周期，加快了产品上市时间，但是SoC产品的测试面临越来越多的挑战，如：The development of integrated circuit technology makes it possible to integrate hundreds of millions of devices in a chip, and can integrate pre-designed and verified IP cores, such as memory, microprocessor, DSP, etc. This diversified integrated chip has become an integrated system capable of processing various information, which is called System-on-a-Chip, SoC. SoC greatly reduces the system cost, shortens the design cycle, and speeds up the time to market, but the testing of SoC products faces more and more challenges, such as:

1、芯片测试点少，可直接控制或观测的测试点有限，通常只能通过芯片有限的输入/输出引脚进行测试，而芯片内部节点很难通过宏观机械装置直接控制或观测。1. There are few test points on the chip, and the test points that can be directly controlled or observed are limited. Usually, it can only be tested through the limited input/output pins of the chip, and the internal nodes of the chip are difficult to directly control or observe through macroscopic mechanical devices.

2、自动测试设备ATE价格昂贵，芯片的设计和制造技术发展速度比ATE的设计和制造技术发展快，芯片的时钟频率已超过了目前最先进的ATE的频率，无法进行全速测试。2. The automatic test equipment ATE is expensive, and the development speed of chip design and manufacturing technology is faster than that of ATE. The clock frequency of the chip has exceeded the frequency of the most advanced ATE at present, and full-speed testing cannot be performed.

3、测试数据量大，SoC中集成的IP越多，所需测试数据量就越大。预计到2014年存储测试向量所需存储器的容量是1999年的150倍，将会超过ATE的存储深度。3. The amount of test data is large. The more IP integrated in the SoC, the greater the amount of test data required. It is estimated that by 2014, the memory capacity required to store test vectors will be 150 times that of 1999, which will exceed the storage depth of ATE.

芯片的测试已成为制约集成电路发展的一个“瓶颈”。已有大量的文献对集成电路的测试方法展开研究，主要有内建自测试(Built-In Self-Test，BIST)和外建自测试两种方法。Chip testing has become a "bottleneck" restricting the development of integrated circuits. There have been a large number of literatures on the testing methods of integrated circuits, mainly including built-in self-test (Built-In Self-Test, BIST) and external built-in self-test methods.

内建自测试方法，依靠芯片自身的资源完成对芯片的测试。此方法将测试模式生成器TPG、测试过程控制和测试响应评价功能模块嵌入在被测电路CUT上，摆脱了对ATE的依赖，减少了测试费用。但由于BIST生成的多是伪随机测试向量，测试时通常存在着抗随机故障(Random Resistant Fault，RRF)，故BIST存在故障覆盖率不高、测试序列较长的弊端。虽然可以通过加权或采用混合模式的BIST等方法来进一步提高测试效率，但随着电路规模的扩大，RRF的增多，要付出的硬件开销将显著增加。The built-in self-test method relies on the chip's own resources to complete the chip's test. This method embeds the test pattern generator TPG, test process control and test response evaluation function modules on the circuit under test CUT, which gets rid of the dependence on ATE and reduces the test cost. However, because most of the test vectors generated by BIST are pseudo-random test vectors, there is usually a Random Resistant Fault (RRF) during the test, so BIST has the disadvantages of low fault coverage and long test sequences. Although the test efficiency can be further improved by weighting or using mixed-mode BIST and other methods, but with the expansion of the circuit scale and the increase of RRF, the hardware overhead to be paid will increase significantly.

外建自测试方法又称为测试源划分技术，此方法将所需的测试向量经过压缩存储在ATE中，测试期间，通过片上的解压电路将其还原施加到被测电路上。它同样是将一些测试资源从ATE移入到芯片中，以达到减少测试数据量、缩短测试时间的目的，可以保证在测试质量不变的情况下降低对ATE的要求。该方法不需要了解被测设计(Design Under Test，DUT)的具体内部结构，可以很好的保护知识产权，因而得到了广泛的应用。The external self-test method is also called the test source division technology. This method compresses and stores the required test vectors in the ATE. During the test, it restores them to the circuit under test through the on-chip decompression circuit. It also moves some test resources from ATE to the chip to achieve the purpose of reducing the amount of test data and shortening the test time, and can ensure that the requirements for ATE are lowered while the test quality remains unchanged. This method does not need to know the specific internal structure of the Design Under Test (DUT), and can protect intellectual property very well, so it has been widely used.

由于SoC测试数据的特殊性，一个好的测试源划分技术，需要在压缩率、解码硬件开销和控制协议三个方面做出权衡。经典的方法有基于游程的编码方法，基于统计的编码方法和基于字典的编码方法。基于游程的编码方法有：Golomb码、FDR码、EFDR码、交替码、交替连续码等编码方法，但这类方法都存在着控制协议复杂等问题；基于统计的编码方法有：选择哈夫曼编码、变长哈夫曼编码，但这类方法存在解压硬件开销大，解码过程复杂等问题；基于字典的编码方法有：LZ77、LZ78、LZW等，但这类方法需要存储字典开销大，同时大量的变长索引使解码非常复杂。Due to the particularity of SoC test data, a good test source division technology needs to make a trade-off in three aspects: compression rate, decoding hardware overhead and control protocol. Classical methods include run-length-based encoding methods, statistical-based encoding methods and dictionary-based encoding methods. Runlength-based encoding methods include: Golomb codes, FDR codes, EFDR codes, alternate codes, alternate continuous codes and other encoding methods, but these methods all have problems such as complex control protocols; statistics-based encoding methods include: choose Huffman Encoding, variable-length Huffman encoding, but these methods have problems such as high decompression hardware overhead and complicated decoding process; dictionary-based encoding methods include: LZ77, LZ78, LZW, etc., but these methods require large dictionary storage overhead, and at the same time The large number of variable-length indexes makes decoding very complicated.

发明内容Contents of the invention

本发明是为避免上述现有技术所存在的不足之处，提供一种块标记的系统芯片测试数据压缩方法，是一种非侵入式的测试数据压缩方法，无需改变被测试的电路结构，尤其是电路中扫描链的结构，首先对相容块或反相相容块进行标记来减少数据量，同时使用异或运算来增加块相容或反相相容的概率，以降低所需测试数据的存储容量，缩短测试应用时间。In order to avoid the shortcomings of the above-mentioned prior art, the present invention provides a system chip test data compression method for block marking, which is a non-invasive test data compression method without changing the circuit structure to be tested, especially It is the structure of the scan chain in the circuit. Firstly, mark the compatible block or anti-phase compatible block to reduce the amount of data, and at the same time use XOR operation to increase the probability of block compatibility or anti-phase compatibility to reduce the required test data The storage capacity shortens the test application time.

本发明解决技术问题所采用的技术方案是：The technical scheme that the present invention solves technical problem adopts is:

本发明块标记的系统芯片测试数据压缩方法的特点是：The characteristics of the system chip test data compression method of the block mark of the present invention are:

用0标记与参考数据块相容的整块待编码数据块，用10标记与参考数据块反相相容的整块待编码数据块，同时动态更新参考数据块来增加参考数据块与待编码数据块相容或反相相容的概率，具体步骤为：Use 0 to mark the entire block of data to be encoded that is compatible with the reference data block, use 10 to mark the entire block of data to be encoded that is inversely compatible with the reference data block, and dynamically update the reference data block to increase the reference data block and the block to be encoded The probability of data block compatibility or reverse compatibility, the specific steps are:

a、采用自动测试模式生成(ATPG)工具，生成确定的完全测试集T；a. Using the Automatic Test Pattern Generation (ATPG) tool to generate a definite complete test set T;

b、按指定的数据块长度k将测试集T分块，如果测试向量的最后一块不足k位，用无关位(don’t-care bits)填充到k位，每块按顺序记为B₁，B₂，B₃，B₄，B₅，……B_m，初始化参考数据块R和待编码数据块B_n(n为整数，2≤n≤m)，即令R＝B₁，B_n＝B₂；b. Divide the test set T into blocks according to the specified data block length k. If the last block of the test vector is less than k bits, fill it with don't-care bits to k bits, and record each block as B₁ in order , B₂ , B₃ , B₄ , B₅ ,...B_m , initialize the reference data block R and the data block to be coded B_n (n is an integer, 2≤n≤m), that is, let R=B₁ , B_n = B₂ ;

c、编码过程，判断参考数据块R与待编码数据块B_n是否相容或反相相容，若R与B_n相容，则将B_n编码为0，同时按位将R与B_n相交(R∩B_n)来动态更新参考数据块R，若R与B_n反相相容，则将B_n编码为10，同时将R反相后(

)按位将与B_n相交(

)来动态更新参考数据块R，若R与B_n既不相容，也不反相相容，则将B_n编码为11B_n，同时进行按位异或(RB_n)操作来动态更新参考数据块R并且增加R中的无关位，从而增加R与后续块相容或反相相容的概率；c. Encoding process, judging whether the reference data block R and the data block B_n to be encoded are compatible or inversely compatible, if R and B_n are compatible, then encode B_n as 0, and at the same time R and B_n are bit by bit Intersect (R∩B_n ) to dynamically update the reference data block R, if R is inversely compatible with B_n , encode B_n as 10, and at the same time reverse R (

) bitwise will intersects with B_n (

) to dynamically update the reference data block R, if R and B_n are neither compatible nor anti-phase compatible, then encode B_n as 11B_n and perform bitwise XOR (RB_n ) operation to dynamically Update the reference data block R and increase the don't care bits in R, thereby increasing the probability that R is compatible or anti-phase compatible with the subsequent block;

d、回溯过程，若R与B_n相容，则用B_n＝R∩B_n来动态更新待编码数据块B_n，若R与B_n反相相容，则用$B=\stackrel{\‾}{R}\∩B_n$来动态更新待编码数据块B_n，逐渐减少n，重复步骤d一直到B_n＝B₁；d. Backtracking process, if R is compatible with B_n , use B_n = R∩B_n to dynamically update the data block B_n to be encoded, if R and B_n are inversely compatible, use$B=\stackrel{\‾}{R}\∩B_{\mathrm{no}}$ To dynamically update the data block B_n to be encoded, gradually reduce n, and repeat step d until B_n = B₁ ;

e、重复步骤c和步骤d一直到所有数据块全部编码，若此时编码中仍然存在无关位，则随机填充这些无关位。e. Repeat step c and step d until all data blocks are completely encoded. If there are still irrelevant bits in the encoding at this time, fill these irrelevant bits randomly.

本发明方法的特点也在于：The inventive method is also characterized in that:

所述测试集T中的测试向量中包含有无关位“X”，且无关位需占测试集总位数的35％～95％。The test vectors in the test set T contain don't care bits "X", and don't care bits need to account for 35%-95% of the total number of bits in the test set.

所述步骤c中与参考数据块相容的待编码数据块用1位来标记编码；与参考数据块反向相容的待编码数据块用2位来标记编码。In the step c, the data block to be coded that is compatible with the reference data block is coded with 1 bit; the data block to be coded that is reverse compatible with the reference data block is coded with 2 bits.

所述步骤c中动态更新参考数据块的方法是，先通过异或操作增加参考数据块中数据的无关位，再根据后续标记编码结果回溯来反标参考数据块和以前编码数据块中的无关位。The method for dynamically updating the reference data block in the step c is to first increase the irrelevant bit of the data in the reference data block through an XOR operation, and then backtrack according to the result of the subsequent mark coding to back-mark the reference data block and the irrelevant bits in the previous coded data block. bit.

本发明方法是通过动态更新参考数据块，来增加待编码数据块与参考数据块相容或反相相容的概率，再通过标记的方法对相容块或反相相容块进行压缩。The method of the invention increases the probability that the data block to be coded is compatible or inversely compatible with the reference data block by dynamically updating the reference data block, and then compresses the compatible block or the inversely compatible block by marking.

与已有技术相比，本发明有益效果体现在：Compared with the prior art, the beneficial effects of the present invention are reflected in:

本发明通过在编码过程中用0来标记与参考数据块相容的整块待编码数据块，用10来标记与参考数据块反相相容的整块待编码数据块，即用1位来代替与参考数据块相容的待编码数据块，用2位来代替与参考数据块反相相容的待编码数据块，完成了整块数据到1位或2位置换，从而实现了数据压缩，同时通过动态更新参考数据块来提高参考数据块与待编码数据块相容或反相相容的概率，不仅大量减少了测试时间，还降低了所需测试数据的存储容量。In the present invention, in the encoding process, 0 is used to mark the entire block of data to be encoded that is compatible with the reference data block, and 10 is used to mark the entire block of data to be encoded that is inversely compatible with the reference data block, that is, 1 bit is used to mark Instead of the data block to be encoded that is compatible with the reference data block, 2 bits are used to replace the data block to be encoded that is inversely compatible with the reference data block, and the whole block of data is replaced by 1 or 2 bits, thereby realizing data compression , and at the same time, the probability that the reference data block is compatible or inversely compatible with the data block to be encoded is increased by dynamically updating the reference data block, which not only greatly reduces the test time, but also reduces the storage capacity of the required test data.

附图说明Description of drawings

图1为本发明的编码和回溯流程图。Fig. 1 is the encoding and backtracking flowchart of the present invention.

图2为本发明的编码和回溯实例示意图，其中，图2(a)为分块后的原始完全测试集示意图；图2(b)为编码与回溯过程示意图。Fig. 2 is a schematic diagram of an example of coding and backtracking in the present invention, wherein Fig. 2(a) is a schematic diagram of the original complete test set after segmentation; Fig. 2(b) is a schematic diagram of the process of coding and backtracking.

图3为本发明的最终解压结构示意图。Fig. 3 is a schematic diagram of the final decompression structure of the present invention.

以下通过实施例，并结合附图对本发明作进一步描述Below by embodiment, in conjunction with accompanying drawing, the present invention will be further described

具体实施方式Detailed ways

实施本发明按如下步骤进行：Implement the present invention and carry out as follows:

1、采用自动测试模式生成(ATPG)工具，生成确定的完全测试集T；1. Use the automatic test pattern generation (ATPG) tool to generate a definite complete test set T;

2、将所述完全测试集T进行分块标记。首先将所述完全测试集T中每个测试向量按k位一块，分割成连续的k位块，如果测试向量的最后一块不足k位，用无关位填充到k位，以保证最终的块的位数都为k，每块按顺序分别记为B₁，B₂，B₃，B₄，B₅，……B_m，初始化参考数据块R和待编码数据块B_n(n为整数，2≤n≤m)，即令R＝B₁，B_n＝B₂；2. Mark the complete test set T into blocks. First, each test vector in the complete test set T is divided into k-bit blocks by k bits, and if the last block of the test vector is less than k bits, it is filled to k bits with irrelevant bits to ensure the final block The number of bits is k, and each block is recorded as B₁ , B₂ , B₃ , B₄ , B₅ , ... B_m in order, and the initialization reference data block R and the data block to be encoded B_n (n is an integer, 2≤n≤m), that is, R=B₁ , B_n =B₂ ;

3、编码过程，判断参考数据块R与待编码数据块B_n是否相容或反相相容，若R与B_n相容，则将B_n编码为0，同时按位将R与B_n相交(R∩B_n)来动态更新参考数据块R，若R与B_n反相相容，则将B_n编码为10，同时将R反相后(

)按位将

与B_n相交(

)来动态更新参考数据块R，若R与B_n既不相容，也不反相相容，则将B_n编码为11B_n，同时进行按位异或(RB_n)操作来动态更新参考数据块R并且增加R中的无关位，从而增加R与后续块相容或反相相容的概率；3. During the encoding process, it is judged whether the reference data block R and the data block B_n to be encoded are compatible or inversely compatible. If R is compatible with B_n , then encode B_n as 0, and at the same time, R and B_n are encoded bit by bit. Intersect (R∩B_n ) to dynamically update the reference data block R, if R is inversely compatible with B_n , encode B_n as 10, and at the same time reverse R (

) bitwise will

intersects with B_n (

) to dynamically update the reference data block R, if R and B_n are neither compatible nor anti-phase compatible, then encode B_n as 11B_n , and perform a bitwise XOR (RB_n ) operation to dynamically Update the reference data block R and increase the don't care bits in R, thereby increasing the probability that R is compatible or anti-phase compatible with subsequent blocks;

在编码过程中用1位数据来标记与参考数据块相容的整块待编码数据块，用2位数据来标记与参考数据块反相相容的整块待编码数据块，其结果是k位整块数据被1位或2位来标记，大大减少了数据位数。In the encoding process, 1-bit data is used to mark the entire block of data to be encoded that is compatible with the reference data block, and 2-bit data is used to mark the entire block of data to be encoded that is inversely compatible with the reference data block, and the result is k The entire block of data is marked by 1 or 2 bits, which greatly reduces the number of data bits.

4、回溯过程，若R与B_n相容，则用B_n＝R∩B_n来动态更新待编码数据块B_n，若R与B_n反相相容，则用$B_n=\stackrel{\‾}{R}\∩B_n$来动态更新待编码数据块B_n，逐渐减少n，重复步骤d一直到B_n＝B₁；4. Backtracking process, if R is compatible with B_n , use B_n = R∩B_n to dynamically update the data block B_n to be encoded, if R and B_n are inversely compatible, use$B_{\mathrm{no}}=\stackrel{\‾}{R}\∩B_{\mathrm{no}}$ To dynamically update the data block B_n to be encoded, gradually reduce n, and repeat step d until B_n = B₁ ;

回溯过程与编码过程正好相反。在编码过程，为了增加R与待编码数据块相容或反相相容的概率，通过异或运算增加R中无关位，因此需要使用回溯过程来反标以前编码块中无关位的值。The backtracking process is the exact opposite of the encoding process. In the encoding process, in order to increase the probability that R is compatible or inversely compatible with the data block to be encoded, the irrelevant bit in R is added by XOR operation, so it is necessary to use the backtracking process to reverse the value of the irrelevant bit in the previous encoding block.

5、重复步骤c和步骤d一直到所有数据块全部编码，若此时编码中仍然存在无关位，则随机填充这些无关位。5. Repeat step c and step d until all data blocks are completely encoded. If there are still irrelevant bits in the encoding at this time, fill these irrelevant bits randomly.

完全确定测试集的生成：Fully determine the generation of the test set:

采用ATPG工具生成确定的完全测试集T，完全测试集T中所含的测试向量能够测试到所有的故障。对ATPG工具的选择，要使其生成的测试向量含有无关位。接下来的步骤就是对生成的确定的完全测试集T进行压缩。The ATPG tool is used to generate a definite complete test set T, and the test vectors contained in the complete test set T can test all faults. The choice of ATPG tool should make the test vector generated by it contain don't care bits. The next step is to compress the generated complete test set T.

相容块或反相相容块标记compatible block or reverse compatible block tag

相容块或反相相容块标记是对分块后的测试集进行相容或反相相容标记，用1位数据来标记与参考数据块相容的k位整块待编码数据块，用2位数据来标记与参考数据块反相相容的k位整块待编码数据块，其结果是k位整块数据可以用1位或2位数据来代替，从而达到数据压缩的目的。测试集中存在大量的无关，使块标记成为可能，其块标记过程如图1所示，若参考数据块R与待编码数据块B_n相容，用0相标记，若参考数据块R与待编码数据B_n反相相容，用10来标记。Compatible block or reverse-phase compatible block marking is to carry out compatibility or reverse-phase compatible marking on the test set after partitioning, and use 1-bit data to mark the k-bit whole block to be coded data block compatible with the reference data block, 2-bit data is used to mark the k-bit whole block of data to be coded that is inversely compatible with the reference data block. As a result, the k-bit whole block of data can be replaced by 1-bit or 2-bit data, thereby achieving the purpose of data compression. There are a lot of irrelevance in the test set, which makes block marking possible. The block marking process is shown in Figure 1. If the reference data block R is compatible with the data block B_n to be encoded, it will be marked with 0 phase. If the reference data block R is compatible with the data block B n to be encoded, The coded data B_n is inversely compatible, denoted by 10.

参考数据块动态更新Dynamic update of reference data blocks

参考数据块动态更新可以增加参考数据块与后续k位待编码数据块相容或反相相容的概率。其方法是先通过异或操作来增加参考数据块的无关位，在向后编码的过程中，如果参考数据块与后续k位待编码数据块相容或反相相容时，再通过回溯过程来反标以前的k位块和参考数据块的无关位，其回溯过程如图1所示，若R与B_n相容，则用B₁＝R∩B₁来修改B₁，若R与B_n反相相容，则用$B_l=\stackrel{\‾}{R}\∩B_l$来修改B₁，此过程一直持续到l＝1或R与B_n既不相容，又不反相相容。The dynamic update of the reference data block can increase the probability that the reference data block is compatible or inversely compatible with the subsequent k-bit data block to be encoded. The method is to first increase the irrelevant bits of the reference data block through an XOR operation. In the process of backward encoding, if the reference data block is compatible or inversely compatible with the subsequent k-bit data block to be encoded, then through the backtracking process To reverse mark the previous k-bit block and the irrelevant bits of the reference data block, the backtracking process is shown in Figure 1, if R is compatible with B_n , then use B₁ =R∩B₁ to modify B₁ , if R and B_n is anti-phase compatible, then use$B_l=\stackrel{\‾}{R}\∩B_l$ to modify B₁ , and this process continues until l=1 or R and B_n are neither compatible nor inversely compatible.

图2(a)和图2(b)给出了一个编码和回溯实例。图2(a)所示，完全测试集T被分成5块，每块长度为8。开始时，参考数据块R的内容为0XXXX1X1，待编码数据块B₂的内容为XXX1XXX1，参考数据块与待编码数据块相容，因此将待编码数据块用0来标记，动态更新(R∩B₂)参考数据块的内容为0XX1X1X1，再通过回溯过程(R∩B₂)来动态更新待编码数据B₁，使其内容为：0XX1X1X1，此过程一直持续到所有待编码数据全部被编码。Figure 2(a) and Figure 2(b) give an example of encoding and backtracking. As shown in Figure 2(a), the complete test set T is divided into 5 blocks, each block has a length of 8. At the beginning, the content of the reference data block R is 0XXXX1X1, and the content of the data block_B2 to be encoded is XXX1XXX1. The reference data block is compatible with the data block to be encoded, so the data block to be encoded is marked with 0, and dynamically updated (R∩ B₂ ) The content of the reference data block is 0XX1X1X1, and then the data to be encoded B₁ is dynamically updated through the backtracking process (R∩B₂ ), so that the content is: 0XX1X1X1, and this process continues until all the data to be encoded is encoded.

可以通过异或运算来增加参考数据块的无关位，因此参考数据块与后续k位待编码数据块相容或反相相容的可能性增大，如图2所示，对B₄进行编码时，待编码数据块B₄的内容为1XX11X0X，参考数据块R的内容1X00X0X0，待编码数据块B₄与参考数据块R既不相容又不反相相容，使用异或操作，将待编码数据块B₄与参考数据块R相异或来动态更新参考数据块R，使参考数据块R的内容变为0XX1XXXX，参考数据块R中无关位增加了，提高了参考数据块R与后续k位待编码数据块相容或反相相容的概率，如待编码数据块B₅与参考数据块R相容。The extraneous OR operation can be used to increase the irrelevant bits of the reference data block, so the possibility of the reference data block being compatible or inversely compatible with the subsequent k-bit data block to be encoded increases. As shown in Figure 2, encoding B₄ , the content of the data block B₄ to be encoded is 1XX11X0X, and the content of the reference data block R is 1X00X0X0. The data block B₄ to be encoded is neither compatible nor inversely compatible with the reference data block R. Using the XOR operation, the Coded data block B₄ is different from reference data block R or to dynamically update reference data block R, so that the content of reference data block R becomes 0XX1XXXX, and the irrelevant bits in reference data block R are increased, which improves the relationship between reference data block R and subsequent The probability that the k-bit data block to be coded is compatible or anti-phase compatible, for example, the data block_B5 to be coded is compatible with the reference data block R.

从图2(b)可以看到，原始数据40位，压缩后只有22位，编码后的数据为：0X1111X10 10 111XX1100X 0，因此，测试数据可以得到大压缩，测试应用时间可以明显缩短。It can be seen from Figure 2(b) that the original data is 40 bits, but only 22 bits after compression, and the encoded data is: 0X1111X10 10 111XX1100X 0. Therefore, the test data can be greatly compressed, and the test application time can be significantly shortened.

解压过程decompression process

解压过程如图3所示。首先，在循环移位寄存器(CSR)中预设首个参考数据块，Ack为选通信号，当从data_in读入的码字为“0”时，data_out信号输出连续的k位“0”，差分后输出，CSR中的数据保持不变；当码字为“10”时，data_out信号输出连续的k位“1”，差分后输出，CSR中的数据被逐位求反；当码字为“11”时，data_out信号输出数据流中随后的连续k位，在Sel信号控制下，多路选择器(MUX)直接输出这k位的同时，CSR中的数据与其逐位异或来更新CSR中的数据。此过程不断循环一直到data_in不再输入数据，即解压结束。The decompression process is shown in Figure 3. First, the first reference data block is preset in the cyclic shift register (CSR), and Ack is a strobe signal. When the code word read from data_in is "0", the data_out signal outputs continuous k-bit "0", Output after difference, the data in CSR remains unchanged; when the code word is "10", the data_out signal outputs continuous k-bit "1", output after difference, the data in CSR is negated bit by bit; when the code word is When "11", the data_out signal outputs the subsequent k bits in the data stream. Under the control of the Sel signal, the multiplexer (MUX) directly outputs the k bits, and the data in the CSR and its bit-by-bit XOR update the CSR. data in . This process continues to loop until data_in no longer inputs data, that is, the decompression ends.

Claims (4)

Translated fromChinese

1、一种块标记的系统芯片测试数据压缩方法，其特征是用0标记与参考数据块相容的整块待编码数据块，用10标记与参考数据块反相相容的整块待编码数据块，同时动态更新参考数据块来增加参考数据块与待编码数据块相容或反相相容的概率，具体步骤为：1, a kind of system chip test data compression method of block mark, it is characterized in that with 0 mark and reference data block compatible integral block data block to be coded, with 10 mark and reference data block anti-phase compatible whole block to be coded data block, and dynamically update the reference data block to increase the probability that the reference data block is compatible or inversely compatible with the data block to be encoded. The specific steps are:a、采用自动测试模式生成(ATPG)工具，生成确定的完全测试集T；a. Using the Automatic Test Pattern Generation (ATPG) tool to generate a definite complete test set T;b、按指定的数据块长度k将完全测试集T分块，如果测试向量的最后一块不足k位，用无关位填充到k位，每块按顺序记为B₁，B₂，B₃，B₄，B₅，......B_m，初始化参考数据块R和待编码数据块B_n(n为整数，2≤n≤m)，即令R＝B₁，B_n＝B₂；b. Divide the complete test set T into blocks according to the specified data block length k. If the last block of the test vector is less than k bits, fill it with irrelevant bits to k bits. Each block is recorded as B₁ , B₂ , B₃ in sequence, B₄ , B₅ , ... B_m , initialize the reference data block R and the data block to be coded B_n (n is an integer, 2≤n≤m), that is, R=B₁ , B_n =B₂ ;c、编码过程，判断参考数据块R与待编码数据块B_n是否相容或反相相容，若R与B_n相容，则将B_n编码为0，同时按位将R与B_n相交(R⌒B_n)来动态更新参考数据块R，若R与B_n反相相容，则将B_n编码为10，同时将R反相后(

)按位将

与B_n相交来动态更新参考数据块R，若R与B_n既不相容，也不反相相容，则将B_n编码为11Bn，同时进行按位异或(RB_n)操作来动态更新参考数据块R并且增加参考数据块R中的无关位，从而增加R与后续待编码数据块相容或反相相容的概率；c. Encoding process, judging whether the reference data block R and the data block B_n to be encoded are compatible or inversely compatible, if R and B_n are compatible, then encode B_n as 0, and at the same time R and B_n are bit by bit Intersect (R⌒B_n ) to dynamically update the reference data block R. If R is inversely compatible with B_n , encode B_n as 10, and at the same time reverse R (

) bitwise will

Intersect with B_n to dynamically update the reference data block R, if R and B_n are neither compatible nor inversely compatible, then encode B_n as 11Bn, and perform a bitwise XOR (RB_n ) operation to dynamically update the reference Data block R and increase the irrelevant bits in the reference data block R, thereby increasing the probability that R is compatible or anti-phase compatible with subsequent data blocks to be encoded;d、回溯过程，若R与B_n相容，则用B_n＝R⌒B_n来动态更新待编码数据块B_n，若R与B_n反相相容，则用$B=\stackrel{\‾}{R}\∩B_n$来动态更新待编码数据块B_n，逐渐减少n，重复步骤d一直到B_n＝B₁；d. Backtracking process, if R is compatible with B_n , use B_n = R⌒B_n to dynamically update the data block B_n to be encoded, if R and B_n are inversely compatible, use$B=\stackrel{\‾}{R}\∩B_{\mathrm{no}}$ To dynamically update the data block B_n to be encoded, gradually reduce n, and repeat step d until B_n = B₁ ;e、重复步骤c和步骤d一直到所有数据块全部编码，若此时编码中仍然存在无关位，则随机填充这些无关位。e. Repeat step c and step d until all data blocks are completely encoded. If there are still irrelevant bits in the encoding at this time, fill these irrelevant bits randomly.2、根据权利要求1所述的块标记的系统芯片测试数据压缩方法，其特征是所述测试集T中的测试向量中包含有无关位“X”，且无关位需占测试集总位数的35％～95％。2. The system chip test data compression method of block marking according to claim 1, characterized in that the test vector in the test set T contains irrelevant bit "X", and the irrelevant bit needs to account for the total number of bits in the test set 35% to 95% of that.3、根据权利要求1所述的块标记的系统芯片测试数据压缩方法，其特征是所述步骤c中与参考数据块相容的待编码数据块用1位来标记编码；与参考数据块反向相容的待编码数据块用2位来标记编码。3, the system chip test data compression method of block marking according to claim 1 is characterized in that in the described step c, the data block to be encoded that is compatible with the reference data block is marked with 1 bit; Use 2 bits to mark codes for compatible data blocks to be coded.4、根据权利要求1所述的块标记的系统芯片测试数据压缩方法，其特征是所述步骤c中动态更新参考数据块的方法是，先通过异或操作增加参考数据块中数据的无关位，再根据后续标记编码结果回溯来反标参考数据块和以前编码数据块中的无关位。4. The system chip test data compression method of the block mark according to claim 1, wherein the method for dynamically updating the reference data block in the step c is to increase the irrelevant bit of the data in the reference data block by XOR operation , and then reverse-mark the irrelevant bits in the reference data block and the previous coded data block according to the result of the subsequent marking encoding.

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