Current mode signaling in electronic data processing circuit

摘要

An electronic data processing circuit uses current mode signalling on a communication conductor, wherein a receiver supplies current to the communication conductor to try and keep a voltage on the conductor constant and measures the current that is needed to do so. A transition coding circuit is coupled between a data source circuit and the communication conductor, for driving the communication conductor in a first state in pulses in response to transitions in the logic signal and in a second state outside the pulses. The level that is used for indicating no change is selected so the current that needs to be supplied by the receiver is smaller when no change is signalled than when a change is signalled. Preferably only a nearly zero quiescent current is needed when there is no change.