Circuits, methods, and apparatus for the dynamic control of calibration data that adjusts the timing of input and output signals on an integrated circuit. This dynamic control allows input and output circuits to self-calibrate by compensating for temperature and voltage changes in an efficient manner, without the need for device reconfiguration. Calibration settings can be maintained while new calibration settings are loaded. Skew between clock and data signals, as well as among multiple data signals, can be reduced. Dynamic control is achieved while consuming only a minimal resources including route paths.