Had a look at couple of other topics that have touched on the subject but there appears to be no solution to micropython implementation. Modbus RTU with RS-485 interface is a half duplex serial uart based protocol and is widely used in the industrial remote control and sensing applications. Importan...
Why not SPI, it already has bidirectional data path?
One extra wiring line can make SPI asynchronous.
As I understand, the whole point of I2C was to use minimal wiring configuration (2 wires)?
As you point out, pyboard has terrible I2C and Uart interrupt and callback implementation.