PDF《第4章 模拟 simulation》

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1 1 VLSI TESTING

16 4.3.2 4.3.2 演绎故障模拟 演绎故障模拟

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1、故障表的计算 、故障表的计算 z 故障表:单个故障使节点A逻辑值与正 常不同,这些故障的故障集LA z 门级电路故障表计算 z 存储元件输出端故障表计算 VLSI TESTING

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2、故障表的传输与故障模拟 、故障表的传输与故障模拟 z 把各个元件的故障表向原始输出端传 输,计算出与电路原始输出端连接的元 件的故障表,就是在给定测试矢量条件 下可测的电路故障集 VLSI TESTING

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3、功能级模拟 、功能级模拟 z 功能块故障表的传输 z 功能块内部故障的故障计算 VLSI TESTING 故障表传播 故障表传播 A B C a two-input AND gate Case 1: A=1, B=1, C=1 at fault-free, LC = LA + LB + {C/0} Case 2: A=1, B=0, C=0 at fault-free, LC = LA * LB + {C/1} Case 3: A=0, B=0, C=0 at fault-free, LC = LA * LB + {C/1} Consider LA is the set of all faults not in LA VLSI TESTING

20 故障表传播 故障表传播 z 两输入或门 A B C Case 1: A=1, B=1, C=1 at fault-free, LC = LA * LB + {C/0} Case 2: A=1, B=0, C=1 at fault-free, LC = LA * LB + {C/0} Case 3: A=0, B=0, C=0 at fault-free, LC = LA + LB + {C/1} VLSI TESTING 故障表传播规则 故障表传播规则 z Let I be the set of inputs of a gate Z with controlling value c and inversion i. Let S be the set of inputs with value c. ( ) { } i c a s Z L L then = if I j j z ? ? ? = ? ∈ } { S U U ( ) { } i c a s Z L L L e S I j j S j j z ? ? ? ? = ? ∈ ∈ } { } { lse U U I VLSI TESTING 演绎故障模拟举例 演绎故障模拟举例I I x x x A B C D E F G H J

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3 faults: B/1, F/0, and J/0 LB = {B/1}, LF = {F/0}, LA =

0 LC=LD = {B/1} VLSI TESTING 演绎故障模拟举例 演绎故障模拟举例II II x x x A B C D E F G H J

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3 faults: B/1, F/0, and J/0 LB = {B/1}, LF = {F/0}, LC=LD = {B/1}, LG = {B/1}, LE = {B/1} VLSI TESTING 演绎故障模拟举例 演绎故障模拟举例III III x x x A B C D E F G H J

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3 faults: B/1, F/0, and J/0 LB = {B/1}, LF = {F/0}, LC=LD = {B/1}, LG = {B/1}, LE = {B/1}, LH = {B/1, F/0} VLSI TESTING 演绎故障模拟举例 演绎故障模拟举例IV IV x x x A B C D E F G H J

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3 faults: B/1, F/0, and J/0 LB = {B/1}, LF = {F/0}, LC=LD = {B/1}, LG = {B/1}, LE = {B/1}, LH = {B/1,F/0}, LJ = {F/0,J/0} VLSI TESTING 演绎故障模拟举例 演绎故障模拟举例V V x x x A B C D E F G H J

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1 1 LB = {B/1}, LF = {F/0}, LC=LD = {B/1}, LG = 0, LE = {B/1}, LH = {B/1,F/0}, LJ = {B/1,F/0,J/0} ? When A changes from

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27 4.3.3 4.3.3 并发性故障模拟 并发性故障模拟 z 采用故障表,基本思路同演绎法 z 结合并行与演绎法 z 故障表的组成及传输 VLSI TESTING

28 并发性模拟仿真步骤 并发性模拟仿真步骤 z 根据给出的测试码列出改变门电路的输 入和输出的全部故障 z 对该门的正常响应和故障响应进行逻辑 模拟,求出其故障表 z 若改变测试码,在上一步只需模拟改变 了的门输入的正常响应和故障........