I have been looking at using an LPC824 instead of an LPC812 to connect to an RS-485 communication line.
Specifically, I am now testing the functionality provided by the RS-485 output enable signal. Section 13.5 or the user manual states:
When RTS signal is configured as an RS-485 output enable, it is asserted at the
beginning of an transmitted character, and de-asserted either at the end of the character,
or after a one character delay (selected by software).
What I am seeing is basically as described, but with a very small pulse in the signal between the end of one character and the start of the next.
Here is a logic analyzer trace showing what I describe:
The top trace shows the six characters being transmitted.
The third trace shows the RS-485 output enable signal - With the pulses in question.
The second trace shows a signal I create with a GPIO - functionality exported from an LPC812 project.
I can possibly put something in the line to filter this glitch out, but I don't see that it should be necessary,