| 摘要 |
In a microcircuit employing LSSD boundary scanning, input and output cells of the circuit are tested using the LSSD boundary scan circuity. Input cells of the circuit are tested by applying two voltages alternately to input cell signal pads and capturing and shifting out through input boundary scan circuitry the responses of the input cells to the voltages. Output cells are tested by shifting a predetermined test pattern through the output boundary scan circuitry. The pattern encloses a set of significant bits which is applied sequentially to the output cells. Each output cell has a gated signal path connecting its signal pad to an internal signal conductor which conducts the response of the output cell to an internal signal path as the significant bits of the bit pattern are scanned past the cell.
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