We've connected our ATSAME70-XPLD to an RS-485 network. We're using the ASF library to facilitate communications, drawing on the functions: usart_write() and usart_init_rs485(), reading is interrupt-driven. We're using USART0 (PB1, PB0).
On the hardware front, we have 3 addressable devices. Each one has selectable termination via a slider switch; these are all disabled (termination off). NULLs frame transmissions from the devices (start with and end with)
We're observing meaningful communication, albeit circularly shifted and inverted. As a temporary workaround, we've implemented a short routine to rectify the data.
We're unclear as to whether the ATSAME70-XPLD has a hardware RS-485 transceiver and wondered whether the inversion might arise from having a single transceiver between master and slave (assuming that the the slave devices employ hardware RS-485 transceivers, and that these invert the signal in a manner analogous to say a MAX232)
Any comments or suggestions are greatly appreciated.