It is very important to make digital designs free of any clock or data glitches to ensure correct functioning. There are many cases where such issues have caused functional failure, or increased design time through incurring extra debug effort. Hence, it is very important for a designer to take care of such issues at the earliest stages of design once flagged by a tool or gate-level synthesis.
Here is his introduction followed by an iframe of the article from EDN magazine.
With the increasing complexity of SoCs, multiple and independent clocks are essential in the design. The design specifications require system level muxing of some of these clocks before they are sent to actual IP. Also, to save power, clock gating cells are inserted in clock paths. While implementing these muxing and gating cells, a designer tends to make mistakes that can lead to glitches. A glitch on a clock signal exposes a chip (or a section of a chip) to asynchronous behavior. A glitch-prone clock signal driving a flip-flop, memory, or latch may result in incorrect, unstable data. This paper discusses structural faults that can lead to glitches in clocks. Also, some bad design practices that lead to glitches in data are discussed. (more…)