Patent ID: 6766486
Filing Date: 2004-07-20
Classification: G01R

Abstract:
A system, comprising:a joint test access group (JTAG) controller having JTAG signals; a test interface unit coupled to the JTAG controller, the test interface unit having several sockets, the test interface unit having drive and compare logic, the test interface unit coupled to multiplex the JTAG signals to one or any combination of sockets in parallel, the test interface unit coupled to read the JTAG signals from one or any combination of the sockets in series, the drive and compare logic coupled to drive test data into the sockets in parallel, to receive test data out from the sockets in series, and to compare the received test data to a threshold voltage; and a programmable power supply coupled to the JTAG controller and to the test interface unit, the programmable power supply to generate a supply voltage to power devices under test, wherein the drive and compare logic comprises an open collector driver coupled to automatically scale to the supply voltage.