Enabling RS485 in full duplex mode on Colibri Evaluation Board v3.2A


We are trying to get RS485 working on the evaluation board 3.2A but it doesnt send or receive anything.
On the evaluation board, the upper RS232 port is disabled by closing JP16. JP13 and JP15 are open for full duplex configuration and UART-B is connected to the PC using a USB to RS485 adapter.

RS485 is enabled in the application using ioctl TIOCSRS485 and the data is being sent to /dev/ttymxc1.

Are we missing something? Thanks in advance.

First some introductory note: RS485 is usually NOT full duplex so you may actually be talking about RS422 instead. If so you may not really want to do that TIOCSRS485 but rather use regular UART hardware flow control. For proper full duplex operation you may also need to ground JP11 pin 2.

Are you sure about the pinout of your cabling between the Colibri Evaluation Board’s X2 Bottom and your USB-to-RS485 adaptor? Please note that officially there exists no real RS422/RS485 pinout standard.

I assume you already consulted the following article on our developer website.