Patent ID: 7757139

Claim:
A boundary scan method, comprising: generating a first parallel unipolarity boundary scan signal, by a scan signal generation apparatus; sending the first parallel unipolarity boundary scan signal to a boundary scan controller; converting, by the boundary scan controller, the first parallel unipolarity boundary scan signal into a serial differential boundary scan signal; and scanning at least one boundary scan device connected between a scan signal output and a scan signal input of the boundary scan controller by using the serial differential boundary scan signal; wherein the scanning process comprises: converting by the boundary scan device the serial differential boundary scan signal into a unipolarity boundary scan signal, transmitting the unipolarity boundary scan signal to a boundary scan chain of the boundary scan device, and converting the unipolarity boundary scan signal into a differential boundary scan signal and transmitting the differential boundary scan signal to a next boundary scan device or to the boundary scan controller.