| 摘要 |
PURPOSE:To conduct a test in a short time by dividing cascaded counter units into >=2 with a signal outputted by a latch circuit group for preset data setting and putting them in operation. CONSTITUTION:When the cascaded counter units 11-1n are tested, specific data are set in latch circuit groups 21-2n which set preset data in the respective units and the output of a decoder 6 is validated. When the decoder 6 outputs the validated signal, a selector circuit 4 fixes the carry input terminal Ci of a counter unit 1m+1 at a H level. Consequently, counter unit groups of higher order than the counter unit 1m+1 and unit groups of lower order than the counter unit 1m operate as one counter respectively. For the purpose, the value of the output terminal 0 of each counter unit 1 is checked to test the operation of the counter in a short time. |
