Abstract: Embodiments herein describe a methodology for performing non-destructive LBIST when booting an integrated circuit (IC). In one embodiment, when powered on, the IC begins the boot process (e.g., a POST) which is then paused to perform LBIST. However, instead of corrupting or destroying the boot mode state of the IC, the LBIST is non-destructive. That is, after LBIST is performed, the booting process can be resumed in the same state as when LBIST began.

Abstract: Disclosed circuitry includes input-output pads, receive flip-flops, and transmit flip-flops coupled to the input-output pads. Data path control circuitry is coupled to data path control flip-flops, the receive flip-flops and the transmit flip-flops. The data path control circuitry is configured to selectably couple the receive flip-flops and the transmit flip-flops to the input-output pads in response to states of the data path control flip-flops. Clock control circuitry is coupled to clock control flip-flops, the receive flip-flops and the transmit flip-flops. The clock control circuitry is configured to selectably apply one of multiple clock signals to the receive flip-flops and the transmit flip-flops in response to states of the clock control flip-flops. A first scan chain is coupled to the clock control flip-flops and the data path control flip-flops. A second scan chain is coupled to the receive flip-flops and the transmit flip-flops.