摘要 |
An integrated circuit is tested when input/output pads of the integrated circuit are unconnected to any external device. In order to do this, for each of a subset of the unconnected input/output pads, a boundary scan register is provided. A test vector is scanned serially into the boundary scan registers. The test vector may then be applied to internal logic of the integrated circuit. While the test is in progress, the value contained within each boundary scan register is applied to an associated input/output pad so that, as a result, the test vector is applied to the subset of the unconnected input/output pads. |