Abstract: Techniques for efficiently performing scan tests are described. In an aspect, a single test pin may be used for both a scan input and a scan output for a scan chain. This multiplexing may reduce test costs and provide other benefits. In one design, an integrated circuit (IC) die includes a scan chain and an input/output (I/O) circuit. The I/O circuit is coupled between the scan chain and a single pad for a single test pin. The I/O circuit multiplexes a scan input and a scan output for the scan chain, provides the scan input from the pad to the scan chain during an input phase of a clock cycle, and provides the scan output from the scan chain to the pad during an output phase of the clock cycle. A bi-directional control signal controls the multiplexing of the scan input and the scan output by the I/O circuit.