With the UART in RS422/485 mode and the serial port disabled via the driver what should be done with unused pins. The 3 signals in question are ‘CTS#’, ‘DCD#’, and ‘RI#’, should they be terminated in some way?
These are floating signals to the UART while in RS422/485 mode. This situation can cause interrupts at times, which causes a stack overflow, which causes an OS crash. In RS232 mode these signals going to the UART are driven. The serial port driver that we have effectively ignores the IRQ's, but the UART still has undefined input signals.
Terry,
use weak pull-up resistors on these unused input signals to keep them in the inactive (high) state. 10K ohm resistors can be used.
Thank you.
Best Regards,
Joe