| 摘要 |
PURPOSE:To reduce external terminals for controlling a test circuit and make test easy by a method wherein all control signals are made at the same level and these signals are sequentially picked up one by one to be at a specific level. CONSTITUTION:In order to individually test m circuit parts 1a, 2a,...ma constituting a data processing circuit EC, parallel registers 1, 2,...m are provided on the output side and a control circuit CNT is installed to control said registers. The circuit CNT has m+1 reset-latch circuits, m NOR circuits, external terminals IC1, IC2 and m output terminals OC1-OCm. When a reset signal having level H is input to the terminal IC2, the circuit CNT forms a means for unifying the level, making control signals C1-Cm which are given from the terminals OC1-OCm to the parallel registers 1-m all at the same level L. When a control clock signal of level H is input to the terminal IC1, the circuit CNT forms a means of sequential selection, and only one control signal sequentially selected is set to level L. |
