Is smarmengol Modbus software serial compatible with half duplex RS485 modules?

Wonderful. :sob:

Looks like there is a bunch more integration left to be done in smarmengol Modbus library to incorporate the software serial, or at least to incorporate AltSoftSerial.

First I'm going to fix the constructors to allow the software serial port to work with the half duplex RS-485 boards.

I can't decide between just changing

this->u8serno = (u8serno > 3) ? 0 : u8serno; to this->u8serno = u8serno;

or also

Forcing the full constructor to always be used (Modbus::Modbus(uint8_t u8id, uint8_t u8serno, uint8_t u8txenpin) )

I leaning towards plan B as it reduces and simplifies the library.