| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit device for testing a ROM decoder, capable of executing multiple detection for the decoder by a digital circuit operation and by a simple structure circuit. SOLUTION: The test control circuit 45 of a test circuit device 47xx outputs 8 pulse signalsΦxx0 toΦxx7 during one test period for outputting one test address respectively at different timings, and takes the logical AND of the pulse signals and the decoding signals of decoders 19 (1 to 8) by NOR gates 41 (1 to 8). Then, the output signals of the NOR gates 41 (1 to 8) are supplied to the NOR gate 42, and the output signals thereof are reversed to trigger the shift register 44 of two stages. COPYRIGHT: (C)2005,JPO&NCIPI
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