nrf7002 compatibility with DM subsystem

RE: nrf7002 compatibility with DM subsystem

cal.rubbo — Tue, 02 Apr 2024 18:33:13 GMT

Thanks Simon. Feel free to close this ticket!

I neglected to mention it in the ticket but my main question was the MPSL interaction between Wi-Fi, BLE, and DM.

Fortunately, the FAE we're working with gave me a great response that steered us away from using the 7002 for DM purposes (we're going with the nRF5340 with a separate Wi-Fi module so we don't need to worry about MPSL conflicts).

Here's his response in case anybody else runs into this (I bolded the important bits):

2.4G will always be active with Nordic DM IIRC, so you may have contention with the 2.4GHz signal from WiFi in that scenario.

You can just leave the 2.4 signal from the WiFi transceiver floating and it should be fine. ((+) nRF700x Diplexer Query - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com))

Or you will need some elbow grease to get it to play nice. In its default state, DM demands all radio attention.

From what I can see, the NDT example simply request the MPSL timeslot infinitely whenever the BLE is not active to do NDT.

The example request timeslot and then keep request to extend the timeslot, see app_timeslot.c

BLE is handled by MPSL directly so no timeslot needed. The timeslot for BLE is already integrated in the MPSL scheduler.

If you are looking to add COEX with WiFi then you will need to look how to handle the MPSL and NDT infinite request for timeslots.

Alternatively, I think you can just use MPSL to halt all 2.4 radio stuff while you do WiFi. too1/ncs-esb-ble-mpsl-demo (github.com)

I vaguely recall some control signals with the 700x transceiver to get the 2.4 signals to play nice with each other. But I can’t remember if it was specific to Bluetooth library.

Given nrf_dm is not really Bluetooth beyond the initial scanning, I don’t know if there was anything baked in to make it work nice with the 2.4 wifi signal regarding those control signals. Bluetooth LE/IEEE 802.15.4 Coexistence (nordicsemi.com)

RE: nrf7002 compatibility with DM subsystem

Simonr — Wed, 27 Mar 2024 08:04:39 GMT

When trying to build on my end I also saw this issue, and I think it is related to the pin forwarding that is added in the nrf5340dk_nrf5340_cpuapp.overlay needs to be added as an overlay in an nRF7002 DK project as well. You also need to add it to the hci_ipc's .overlay file as well.

 /* Enable pin forwarding to network core. The selected pins will be used by
  * Distance Measurement module for debug purposes.
  *
  * Note: Pay attention to assign the same GPIO pins as those provide in network core DTS overlay.
  */
&gpio_fwd {
	compatible = "nordic,nrf-gpio-forwarder";
	dm-gpio-if {
		gpios = <&gpio0 26 0>,
			<&gpio0 27 0>;
		};
};

	/* The selected pins will be used by Distance Measurement module for debug purposes.
	 *
	 * Note: Pay attention to select the same GPIO pins
	 * in the application core DTS overlay's gpio_fwd node.
	 */
	dm_gpio {
		compatible = "gpio-leds";
		dm_ranging: dm-ranging {
			gpios = <&gpio0 27 GPIO_ACTIVE_LOW>;
			label = "DM Ranging Pin";
		};
		dm_add_request: dm-add-request {
			gpios = <&gpio0 26 GPIO_ACTIVE_LOW>;
			label = "DM Add request Pin";
		};
	};

Best regards,

Simon

RE: nrf7002 compatibility with DM subsystem

cal.rubbo — Tue, 26 Mar 2024 12:05:03 GMT

I could definitely be wrong but I don't think that's the issue here.

Here's my project configurations, showing nrf_dm/prj.conf and nrf_dm/child_image/hci_ipc.conf. You can see both files have CONFIG_MPSL=y

Note: I'm using SDK v2.6.0 so that's why it's using hci_ipc.conf and not hci_rpmsg.conf like in Maria's reply.

RE: nrf7002 compatibility with DM subsystem

Simonr — Tue, 26 Mar 2024 09:58:45 GMT

I don't think this is an issue with the nRF7002 being in conflict with the DM subsystem, but rather that the application doesn't have CONFIG_MPSL=y set in the .conf file for both the application and network core images you're building for. Please check out Maria's reply in this case where she describes this in detail.

Best regards,

Simon