Patent ID: 7120831

Claim:
An in-circuit emulator system comprising: an in-circuit emulator installed into a target system in order to debug hardware of the target system mounting on a microcomputer and software that operates the microcomputer; in place of the microcomputer of the target system, a personal computer connected to the in-circuit emulator through a communication interface cable; and an in-circuit emulator debugger that is operated on the personal computer to control the in-circuit emulator, wherein the in-circuit emulator includes a frequency data register that stores clock frequency data set by the in-circuit emulator debugger; a phase locked loop synthesizer that generates a clock based on the clock frequency data stored in the frequency data register; and a microcomputer that executes the software and a control program of the in-circuit emulator in place of the microcomputer to be mounted on the target system operated by the generated clock.