| 摘要 |
PURPOSE:To enable the testing of a sequence circuit by a normal scan path system while facilitating the testing with the activation of a desired functional block by providing a bypassing circuit in parallel with a functional unit. CONSTITUTION:A state switching signal 8 and an output selection signal 17 select the upper position when the logical value thereof is ''0'' while doing the lower position when it is ''1''. In the normal operation mode, 8(1)=17(1)=8(2)=0 is set and a specified function is realized by use of a plurality of functional blocks. On the other hand, by setting 8(1)=1, 17(1)=0, 8(2)=1, 17(2)=0, a scan path is built to enable a shift register, making the testing ready. By setting 8(1)=0, 17(1)-1, 8(2)=1 and 17(2)=0, a functional unit 2(1) is bypassed at a testing can be done as a combination circuit. By setting 8(1)=0, 17(1)=1, 8(2)= 1 and 17(2)=1, a functional bolck 9(1) alone is activated and a testing can be done.
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