Pin-scan-in type LSI logic circuit, pin-scan-in system driving circuit, and method of testing circuit-mounting substrates

摘要

A pin-scan-in system driving circuit drives a pin-scan-in circuit to test short-circuit of the wirings or breaking of the wirings in the circuit-mounting substrate, and this circuit is driven using a reduced number of gates. The pin-scan-in system driving circuit drives the pin- scan-in circuit provided in an LSI logic circuit, and the LSI logic circuit is provided with a pin-scan-in circuit selector which selects the pin-scan-in circuit and a selected condition-holding circuit which holds the condition selected by the pin-scan-in circuit selector.