Circuitry for driving a pin includes a first resistive circuit connected to the pin, a first transistor circuit to connect the first resistive circuit to a logic level voltage in response to a trigger voltage, the first transistor circuit and the first resistive circuit together defining a termination impedance, and a driver circuit to apply the trigger voltage to the first transistor circuit. The driver circuit includes counterparts to the first resistive circuit and the first transistor circuit. The counterparts define a counterpart impedance that is controlled to control the trigger voltage and thereby control the termination impedance.