iMajik: Making 1149.1 TAPs disappear and reappear in SoCs and 3D packages

The paper introduces a new protocol using just the TCK and TMS to transmit address and data called iMajik. iMajik is a method which 1149.1 based tools can use without modification to make 1149.1 TAPs appear and disappear, add compliance-enable without pins and broadcast commands to P1687 instruments. iMajik uses simple Test-Logic-Reset sequences with Run-Test-Idle to enable an on/off switch of various DFT capabilities. IEEE 1149.1 compliant TAP interfaces disappear to simple pass-through wires using the iMajik method. The sequences communicate an `address´ which enables one or more the TAP interfaces and a `command´. iMajik may also have benefits for P1687 instrument chains and on-chip routing of the P1687 network.