nable signal, when SE = 1: all the registers in the scan chain acts as asingle shift register, when SE = 0: The output of the register passes through the combinational logic following it (this is used to to test nodes in the circuit). SE is connected to all the SE pins of all the scan flops.</li>
    <li>test_mode: A signal to indicate whether the chip is operating in the functional mode or the test mode.</li>
    <li>SI: The input to the scan chain. The width of this port is the number of the scan chains</