noel vellemans

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5 years, 11 months ago.

LPC1768/ LPC546xx : Dual VIRTUAL COMPORTS with one USB-connection ?

Hello

I wonder if it possible ( or if someone has already tried it) to have 2 'USB-CDC' comports enabled over ONE physical USB-connection, on a LPC1768 and/or LPC546xx microcontroller

Any URL's / pointers that can guide me ?

Thank You

2 Answers

David Thedens
5 years, 11 months ago.

Not sure. But the only way I can think of is a composite device. That is, a USB device that has more than one device class in its descriptors. In your case, the two devices would both be CDC devices. However I am not sure how windoes would handle it. Should be easy enough to try. take a standard CDC descriptor and make it into a composite device. You don't have to implement much functionality of the second device unless windows recognizes it.

I've seen several windows supported devices that implement two (or more) com ports over a single USB link so it is certainly possible in windows. I've never looked too closely to see how they are doing it.

posted by Andy A 24 Jan 2019
Joseph Gorse
5 years, 7 months ago.

It's been done for STM32F103: Issue: https://github.com/ARMmbed/DAPLink/issues/262 Code: https://github.com/Awais174/DAPLink/commit/4ccea1951dc24c9c109901213baa1e003212bacd#comments