10-19-2018 01:09 PM
I'm curious if there is any issue with building an internal RS485 segment in PL.
External connection to an RS485 bus would be made through a single interface, while I could have multiple internal interfaces using UART 16550 modules.
I'm assuming I could do this by connecting the RX/TX and RS/CTS with appropriate logic to distribute internally and propagate the OR of all signals to external.
I don't see any technical reason this would fail in either the RS485 or logic sides, does anyone else?
10-21-2018 11:26 PM
RS485 usually has a pretty bad Common Mode voltage that might destroy your FPGA. Additionally, the signal levels of about 5V would also damage any FPGA I know.
I would recommend using an external RS485 transceiver and use a standard UART internally.