A circuit, system and method adjusts a reference voltage, such as an internal or external reference voltage V.sub.REF, in response to a first voltage at a first contact, such as a pin on a memory controller used for reading or writing data, and a second voltage at a second contact in embodiments. Logic is coupled to the first and second contacts to provide a control signal in response to the first and second voltages. A comparator provides an input signal to the logic in response to a target reference voltage and the reference voltage during a calibration or initialization mode of operation. In an alternate embodiment, a plurality of data values at a first contact are compared to a predetermined plurality of test data. An up/down signal is then provided to a counter and a register stores a counter value used to provide a reference voltage.