Test device for testing on-chip clock controller having debug function

Abstract

A test device is configured to test an on-chip clock controller having a debug function. The test device includes a scan chain and a test circuit. The scan chain includes N flip-flop circuit(s), each of which stores a first input signal as a storage signal, then stores a second input signal as the storage signal or keeps the current storage signal according to an input clock, and then output the storage signal. Since the first and second input signals are different, the outputted storage signal indicates whether the flip-flop circuit stores the second input signal or keeps the current storage signal according to the input clock under predetermined test setting, and indicates whether circuits under test (CUTs) for transmitting the input clock operate normally. The test circuit outputs an observation clock of the on-chip clock controller or an independent clock as the input clock according to the predetermined test setting.