| 摘要 |
PURPOSE:To detect a fault by the scan path method by allowing a digital transmitter to use an internal clock so as to latch parallel data outputted by itself when a switching control pulse is not active. CONSTITUTION:An S/P conversion section 1 fetches serial data inputted synchronously with a transmission clock SCLK and outputs parallel data in a timing of an S/P conversion pulse SPP synchronously with the transmission clock. An extension circuit 3 generates an extension pulse LP resulting from extending the pulse SPP by a bit length over a period of an internal clock. A differentiation circuit 4 differentiates a trailing edge of the pulse LP synchronously with the internal clock to generate a switching control pulse CTP. A clock transfer section 2 latches the parallel data from the conversion section 1 when the pulse CTP is active and parallel data outputted by itself in other cases based on the internal clock ICLK and the latched data are outputted. |
