I'm looking at using the RS485 to communicate between two Arduinos. I'm trying to wrap my head around the current requirements though... If I connect a driver to a receiver through a differential pair, then what concerns do I have regarding current sourcing and sinking, as the datasheets I've seen all seem to point to negative currents somewhere along the line.
Am I not interpreting the datasheets correctly. Is it more of a case of a small amount of current will flow from the arduino to the driver. Likewise, a small amount of current will flow from the receiver to the arduino, but for the most part the driver and receiver will source and sink current from their relevant power supplies?
I have included the relevant parts of the datasheet as follows. For the driver (datasheet):
The relevant receiver (datasheet) extract is as follows:
Edit (example circuit)
To clarify the given answer, if I had a circuit below (it cannot be simulated) and had a driver and receiver wired up with the diode it would work okay as the driver and reciever would not attempt to sink current to their respective control pins?
Also, the driver I can see sources 200mA from VCC, but sinks a minimum of 200mA into GND, which is a standard forward voltage circuit... Is this correct? (I'm not too familiar as yet with reverse voltages, sinking current etc...). However the input current (assuming that is what I'm calling the 'in' port that connects to the microcontroller) has a +- of 1 uA, which I am assuming means it can sink or source current from the microcontroller. If this is the case, it would seem to me the diodes would stop this circuit working?