Enable mcumgr features on NRF5340 DK board while Bluetooth HCI_USB program is running

[Utsav R Shah]

Hello community,

I am trying for multiple firmware updates for my NRF5340 DK board. 

What I am doing is I have build and flashed the SMP server sample program found /zephyr/samples/subsys/mgmt/mcumgr/smp_svr

After flashing this application, I can see my board recognised as a ttyACM0 device while I perform ls /dev.

Using the mcumgr tool I am also able to flash the Bluetooth HCI_USB sample program and after confirming the image and resetting the board, the board now acts as a bluetooth controller. I can verify this using the bluetoothctl command.

Now If I want to do a firmware upgrade, I dont have any way in the HCI_USB application to go back to smp server application. How can I perform multiple firmware updates using mcumgr?

Can virtual com port concept be useful here? If yes then I would like to have a detailed tutorial for this .

[Utsav R Shah]

Sigurd Hellesvik  Thank you so much for taking the time to understand my problem. That is really appreciable.

Looking at the zephyr.dts file present in build/zephyr directory, I could find this code snippet that I have attached. I think this may be how cdc_acm is defined 

usbd: zephyr_udc0: usbd@36000 {
				compatible = "nordic,nrf-usbd";
				reg = < 0x36000 0x1000 >;
				interrupts = < 0x36 0x1 >;
				num-bidir-endpoints = < 0x1 >;
				num-in-endpoints = < 0x7 >;
				num-out-endpoints = < 0x7 >;
				num-isoin-endpoints = < 0x1 >;
				num-isoout-endpoints = < 0x1 >;
				status = "okay";
				cdc_acm0: cdc_acm0 {
					compatible = "zephyr,cdc-acm-uart";
				};
				cdc_acm1: cdc_acm1 {
					compatible = "zephyr,cdc-acm-uart";
				};
			};

[Sigurd Hellesvik]

And then we can have a look at where the sample I mentioned sets up cdc_acm:

zephyr_udc0: &usbd {
	compatible = "nordic,nrf-usbd";
	status = "okay";

	cdc_acm_uart: cdc_acm_uart {
		compatible = "zephyr,cdc-acm-uart";
	};
};

You see how they defined cdc_acm_uart?
cdc_acm_uart is just the name set in the example. Which name did you give the same type of node in your dts?

[Utsav R Shah]

I'm actually confused now on how to do this. Since I am completely new to this, I actually need some direct hand holding for this. Any chance I can connect with someone directly from the community or with you?

[Sigurd Hellesvik]

I will try to continue to explain a bit further. In your code you got:

	cdc_acm0: cdc_acm0 {
		compatible = "zephyr,cdc-acm-uart";
    };

And the example got:

	cdc_acm_uart: cdc_acm_uart {
		compatible = "zephyr,cdc-acm-uart";
	};

Your node is named cdc_acm0, and the sample node is named cdc_acm_uart.
It is the name of the node which you point to in the "chosen" part of the DTS.

The error message is because you use cdc_acm_uart for your chosen node. But cdc_acm_uart does not exist for your code. Instead the CDC node in your code is named cdc_acm0

Does that make sense?

[Utsav R Shah]

Yes I now kind of understand what you are saying and I have modified my overlay file accordingly. Please have a look : 

/ {
	chosen {
	   zephyr,code-partition = &slot0_partition;
	   zephyr,out-usb = &cdc_acm1;
	   zephyr,uart-mcumgr = &cdc_acm0;
	   zephyr,bt-mon-uart = &cdc_acm1;
	   zephyr,bt-c2h-uart = &cdc_acm2;
	   
	};
 };

&zephyr_udc0 {
	cdc_acm0: cdc_acm0 {
		compatible = "zephyr,cdc-acm-uart";
	};
	cdc_acm1: cdc_acm1 {
		compatible = "zephyr,cdc-acm-uart";
	};
	cdc_acm2: cdc_acm2 {
		compatible = "zephyr,cdc-acm-uart";
	};
};

&uart0 {
	status = "okay";
};

Now the code compiles successfully and I was able to flash it. But the problem still remains the same. I am not able to see the device as a bluetooth controller. But when I check the device list, I can see the 3 ACM ports that are created. Only the default bluetooth controller of my laptop is visible.