SIGNAL OBSERVING METHOD/DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a signal observing method for easily waveform-observing the data signal of a target circuit. SOLUTION: A signal detection part 21 judges whether the data signal DT outputted to a common bus 15 at that time is a signal for the target circuit or not based on information stored in a memory. The signal detection part 21 outputs the signal as it is when the signal at that time is that for the target circuit based on a judged result. When the signal is that for a circuit except for the target circuit, the signal is masked and it is outputted as the signal of a prescribed level. A logic simulator 23 stores the output signal of the signal detection part 21 in a trace memory 24.