A scan interface for an integrated circuit includes a scan clock and a scan mode signal. The scan mode signal is indicative of whether or not scan is active, and may be used by dedicated scan circuitry in integrated circuit. Such circuitry may be inactive if the scan mode indicates that scan is inactive, and active if the scan mode indicates that scan is active. For example, the scan circuitry may not toggle is scan is inactive. The scan circuitry may present a reduced load to functional circuitry if scan is inactive. In some embodiments, static and dynamic scan circuits are included for use with static and dynamic logic circuits, respectively.
A scannable latch is disclosed. The scannable latch includes a dynamic circuit, two cross-coupled NAND gates coupled to the dynamic circuit, and a pair of stacked transistors coupled to the dynamic circuit. One of the stacked transistors is for receiving data signals, and the other stacked transistors is for receiving scan in signals.
An apparatus includes a plurality of macrocells formed from logic capable of performing one or more functions. The apparatus also includes a clock tree capable of receiving a clock signal and providing at least one copy of the clock signal to each macrocell. The clock tree includes a local branch within each macrocell, where each local branch is capable of providing at least one copy of the clock signal. In addition, the apparatus includes at least one glitch detection circuit capable of detecting a glitch in one or more copies of the clock signal provided by the local branches in the macrocells.
