topic Re: [LPC55S69] Zephyr: uart-mcumgr on shared flexcomm port in Zephyr Project

[LPC55S69] Zephyr: uart-mcumgr on shared flexcomm port

ED8500 — Fri, 07 Nov 2025 14:26:57 GMT

Hi all,

I have an application running on the NXP that communicates with a host application over uart flexcomm0. Working fine. What I want to implement is DFU (using mcumgr from the same host) but I only have this one single flexcomm0 between the host and NXP. So custom commands and DFU need to go over the same flexcomm.

I found a post that says mcumgr can be on a shared uart by just adding CONFIG_MCUMGR_TRANSPORT_SHELL=y to the prj.conf. But seems like it doesn't work. Tried all kinds of combinations but to no avail.

I'm talking about this:

zephyr,console = &flexcomm0;
zephyr,shell-uart = &flexcomm0;
zephyr,uart-mcumgr = &flexcomm0;

My custom parser works fine until the point I enable the CONFIG_MCUMGR=y, so I must be missing some config flags probably.

So question is: can both be on the same port? If yes, what flags should be set (or not set) in the prj.conf?

Thanks in advance!

Re: [LPC55S69] Zephyr: uart-mcumgr on shared flexcomm port

carlos_o — Fri, 14 Nov 2025 17:16:31 GMT

Hi @ED8500

Apologies the late reply,

The lpcxpresso55s69 has a DFU example, could you please try to add the same configurations to your project?

the example overlay is to enable dfu permanent download

Re: [LPC55S69] Zephyr: uart-mcumgr on shared flexcomm port

ED8500 — Mon, 17 Nov 2025 09:19:02 GMT

Thanks Carlos for the feedback. The trick was to remove the shell-uart from the app.overlay file and keep the console and uart-mcumgr. In the prj.conf replace the CONFIG_MCUMGR_TRANSPORT_UART by CONFIG_MCUMGR_TRANSPORT_SHELL. I'm currently testing it but it seems to work nicely...

Re: [LPC55S69] Zephyr: uart-mcumgr on shared flexcomm port

carlos_o — Wed, 19 Nov 2025 16:17:41 GMT

Thanks for sharing, let me know if you have issues