Patent ID: 7949919

Claim:
A microelectronic device comprising: an IC core; a boundary scan test interface sharing with the IC core a pre-selected number of pins, which include at least one shared pin being switchable between a scan test mode and a normal function operation mode; a test access port controller for activating the boundary scan test mode to route a test signal to be input or output through the pre-selected shared pins in response to a mode selection signal; at least one bi-directional circuit connected to the at least one shared pin, the at least one bi-directional circuit having a control input that determines whether the shared pin functions as an input or an output; and a multiplexer having an output that is connected to the control input of the at least one bi-directional circuit, the multiplexer having a control input that is determined by a logical combination of the mode selection signal and a reset state of the test access port controller.