Data check timing paths

Data check is a timing check, either picked from timing model or user-defined, between two related data signals. Thus, data check timing path is a timing path, wherein both reference signal and constrained signal are data signals launched by same or related clocks. Figure 1 below shows an example data check path where both signals are launched from positive edge-triggered flip-flops. Based upon the type of check being formed (data setup check or data hold check), we can categorize these as data-setup-check path or data-hold-check path.

Constraining data-check timing paths: To constrain data-check timing paths, we first need to ensure that there is a data-check associated with the signals in question. It can either be defined in the timing model being picked or we can define using SDC construct "set_data_check". Once data check is defined, we can simply ensure that both the reference signal and constrained signal are launched from same clock or related clock to see data-check timing path reported.