Abstract: An orthogonal data link is provided by a first digital device, a second digital device, and a bus coupling the first digital device to the second digital device. The first digital device has a first transmitter that encodes data of the first device with a first code (e.g., [1,1]), for transmission on the bus. The second device has a second transmitter that encodes data of the second device with a second code (e.g., [0,1] or [1,0]), for transmission on the bus. The first device has a first receiver that renders the second data by (a) multiplying signals of the bus with the second code and (b) integrating over a periodicity of the codes. The second device has a second receiver that renders the first data by (a) multiplying signals of the bus with the first code and (b) integrating over a periodicity of the codes.

Abstract: A reference voltage is moved dynamically towards a voltage level of the last received value. The movement takes place over a predetermined fraction of a bit-time. The amount of movement is limited so that successive logical values don't result in an unusable reference voltage level. When the output of a receiver changes, a state machine sequences the selection of analog reference voltage inputs to a multiplexer to move an output reference voltage towards a steady-state signal voltage level for the value that was just received. When the sequence is complete, the state machine keeps the last value selected on the output until the output of the receiver changes value.