METHOD AND APPARATUS FOR TESTING MULTI-DIE INTEGRATED CIRCUITS

An example integrated circuit (IC) die in a multi-die IC package, the multi-die IC package having a test access port (TAP) comprising a test data input (TDI), test data output (TDO), test clock (TCK), and test mode select (TMS), is described. The IC die includes a Joint Test Action Group (JTAG) controller having a JTAG interface that includes a TDI, a TDO, a TCK, and a TMS, a first output coupled to first routing in the multi-die IC package, a first input coupled to the first routing or to second routing in the multi-die IC package, a master return path coupled to the first input, and a wrapper circuit configured to couple the TDI of the TAP to the TDI of the JTAG controller, and selectively couple, in response to a first control signal, the TDO of the TAP to either the master return path or the TDO.