Send DTR On Serial Connect

I’m attempting to use an Arduino Leonardo to communicate with RealDash over USB serial. Unfortunately the Leonardo requires a DTS to be sent by RealDash in order to enable serial communication. Could this be added?

What are the VID and PID values of the serial port? I can enable DTR on that device based on those values.

Thanks. They are:

VID: 2341
PID: 8036

This is a good interim solution, but for the future would it be possible to add a button (like on many serial terimnals) to enable/disable DTR when configuring the serial device?

Will think what we can do.

Thanks. I’m relying on a USB TTL dongle for testing but it’s not terribly reliable and doesn’t power the board. It’s not a good solution once it’s installed in the vehicle. Being able to connect directly over the native USB would be the best route.

Typically Arduino devices allow serial comms without any settings just by waiting for a couple of seconds after connect. The Arduino device will then switch itself from code upload mode to normal serial mode. RealDash already has this delay implemented on certain connection types. What connection type you are using?

That is not the case here. The Arduino Leonardo’s USB Serial implementation requires a DTR before it transmits. Without a DTR from RealDash it will never begin transmitting.

You can see that implemented here: https://github.com/arduino/ArduinoCore-avr/blob/44dc454b9382298fa8be542c8c92e7944d9aa21e/cores/arduino/CDC.cpp#L128

The built in USB serial is much more reliable at high speeds than the external TTL converter I’m forced to use. Please consider adding a DTR for the provided IDs.

Next version will have ‘advanced’ settings for serial connection for manual baud rate selection, and options to SET/CLEAR DTR or RTS.

Thanks! I’ll test it once it’s available.