Zephyr + OpenThread Radio Co-Processor (RCP)

[Louis]

I successfully used the OpenThread nRF52840 USB dongle support provided by the OpenThread project to implement the radio coprocessor functionality.

However, I had no success whatsoever trying to do the same with the release 1.7 of the nRF Connect SDK.

west build -b nrf52840dongle_nrf52840 -- -DOVERLAY_CONFIG="overlay-usb.conf;overlay-rcp.conf;overlay-logging.conf;overlay-vendor_hook.conf"

The border router reports:

user.crit otbr-agent[4788]: [CRIT]-PLAT----: HandleRcpTimeout() at /usr/src/debug/ot-br-posix/0.2+gitAUTOINC+5de1086daa-r0/git/third_party/openthread/repo/src/lib/spinel/radio_spinel_impl.hpp:2169: RadioSpinelNoResponse

when it tries to talk to the dongle. Indeed, I also tried to port the nRF5340DK to the design targeted at a physical UART interface with the same result and I do see outgoing requests which are never answered by the RCP based on what I see on a scope. Same result with different baud rates with or without hardware flow control.

Is the functionality supported within the zephyr-based nRF Connect SDK and are there plans to also port the functionality to the nRF5340? Thanks.

[Sigurd Hellesvik]

Hi Louis

It should bepossible to run the RCP on the nRF5340.

But before porting the RCP, let's make sure it works on either of the supported nRF52840 Dongle or nRF52840DK.
For the correct configurations for using the coprocessor with the OpenThread Border Router, see Configuring a radio co-processor.

Are you able to make the dongle work with these  configurations?

Regards,
Sigurd Hellesvik

[Louis]

Thanks,

overlay-thread_1_2.conf overlay-usb.conf was certainly missing, but still the same result with the nRF52840 Dongle repeating the exact steps documented here. We just ordered the nRF52840DK. 

[Sigurd Hellesvik]

Hi

Are you using the same commit id for the Border Router as explained in the guide?

Regards,
Sigurd Hellesvik

[Louis]

Sorry for the late response. I built the border from yocto using meta-oniro. I first updated to the new (1.8) release of the nRF Connect SDK. The dongle started to answer, but complained that the API were not compatible. So, I also upgraded to a newer openthread release on the router side and managed to get both the nRF52840 USB dongle and nRF52840DK (USB and UART) up and running with the border router. I tried to add support for the nRF5340DK:

--- /opt/nrfconnect-sdk/nrf/samples/openthread/coprocessor/boards/nrf5340dk_nrf5340_cpuapp.overlay	1970-01-01 00:00:00.000000000 +0000
+++ ./coprocessor/boards/nrf5340dk_nrf5340_cpuapp.overlay	2022-01-25 12:32:53.177692122 +0000
@@ -0,0 +1,24 @@
+&uart1 {
+    status = "okay";
+    current-speed = <460800>;
+    status = "okay";
+    hw-flow-control;
+    rts-pin = <37>;
+    cts-pin = <36>;
+    tx-pin = <33>;
+    rx-pin = <32>;
+    cts-pull-up;
+    rx-pull-up;
+};
+
+/ {
+	chosen {
+		zephyr,ot-uart = &uart1;
+	};
+};

and the complication:

west build -p always -b nrf5340dk_nrf5340_cpuapp  -- -DOVERLAY_CONFIG="overlay-rcp.conf $ZEPHYR_BASE/../nrf/samples/openthread/cli/overlay-thread_1_2.conf" -DCONFIG_XOROSHIRO_RANDOM_GENERATOR=y

but compilation fails:

/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c: In function 'nrf5_stop':
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c:659:6: warning: implicit declaration of function 'nrf_802154_sleep_if_idle'; did you mean 'nrf_802154_sleep'? [-Wimplicit-function-declaration]
  659 |  if (nrf_802154_sleep_if_idle() != NRF_802154_SLEEP_ERROR_NONE) {
      |      ^~~~~~~~~~~~~~~~~~~~~~~~
      |      nrf_802154_sleep
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c:659:36: error: 'NRF_802154_SLEEP_ERROR_NONE' undeclared (first use in this function); did you mean 'NRF_802154_RX_ERROR_NONE'?
  659 |  if (nrf_802154_sleep_if_idle() != NRF_802154_SLEEP_ERROR_NONE) {
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                                    NRF_802154_RX_ERROR_NONE
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c:659:36: note: each undeclared identifier is reported only once for each function it appears in
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c: In function 'nrf5_receive_at':
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c:782:2: warning: implicit declaration of function 'nrf_802154_receive_at'; did you mean 'nrf_802154_receive'? [-Wimplicit-function-declaration]
  782 |  nrf_802154_receive_at(start - TXTIME_OFFSET_US, TXTIME_OFFSET_US, duration, channel, id);
      |  ^~~~~~~~~~~~~~~~~~~~~
      |  nrf_802154_receive
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c: In function 'nrf5_config_csl_period':
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c:787:2: warning: implicit declaration of function 'nrf_802154_receive_at_cancel'; did you mean 'nrf_802154_receive_failed'? [-Wimplicit-function-declaration]
  787 |  nrf_802154_receive_at_cancel(DRX_SLOT_PH);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |  nrf_802154_receive_failed
/opt/nrfconnect-sdk/zephyr/drivers/ieee802154/ieee802154_nrf5.c:790:2: warning: implicit declaration of function 'nrf_802154_csl_writer_period_set' [-Wimplicit-function-declaration]
  790 |  nrf_802154_csl_writer_period_set(period);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[354/396] Building C object zephyr/subsys/net/ip/CMakeFiles/subsys__net__ip.dir/net_if.c.obj
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: /usr/local/bin/cmake --build /home/workspace/coprocessor/build

Finally, it will compile from the main nRF Connect branch (overlay-thread_1_2.conf doesn't seems to be required anymore):

west build -p always -b nrf5340dk_nrf5340_cpuapp -- -DOVERLAY_CONFIG="overlay-rcp.conf" -DCONFIG_OPENTHREAD_THREAD_VERSION_1_2=y -DCONFIG_XOROSHIRO_RANDOM_GENERATOR=y

with a few warnings about missing declarations:

/home/workspace/coprocessor.main/src/nrf_802154_radio_wrapper.c: In function 'nrf_802154_radio_wrapper_auto_ack_get':
/home/workspace/coprocessor.main/src/nrf_802154_radio_wrapper.c:16:9: warning: implicit declaration of function 'nrf_802154_auto_ack_get'; did you mean 'nrf_802154_time_get'? [-Wimplicit-function-declaration]
   16 |  return nrf_802154_auto_ack_get();
      |         ^~~~~~~~~~~~~~~~~~~~~~~
      |         nrf_802154_time_get
/home/workspace/coprocessor.main/src/nrf_802154_radio_wrapper.c: In function 'nrf_802154_radio_wrapper_auto_ack_set':
/home/workspace/coprocessor.main/src/nrf_802154_radio_wrapper.c:21:2: warning: implicit declaration of function 'nrf_802154_auto_ack_set'; did you mean 'nrf_802154_ack_data_set'? [-Wimplicit-function-declaration]
   21 |  nrf_802154_auto_ack_set(enabled);
      |  ^~~~~~~~~~~~~~~~~~~~~~~
      |  nrf_802154_ack_data_set

but the co-processor remains dead silent (also tried UART over USB with the same result) as it was the case with the release 1.7 of nRF Connect.

[Sigurd Hellesvik]

Hi

I am trying to make the nRF5340DK work as RCP for a border router, but has not figured it out yet.
I hope to solve this out and return with an answer tomorrow or maybe Monday.

Regards,
Sigurd Hellesvik

[Sigurd Hellesvik]

Hi

It seems to build fine for me when i build for nrf5340dk_nrf5340_cpuapp_ns in v1.8.0.
Unfortunately, I do not have an OTBR at hand, so i can not check that it works with the Border Router.

Are you able to make it work when building as ns?

Regards,
Sigurd Hellesvik

[Louis]

Did you include the overlay-thread_1_2.conf configuration file from the cli sample?

west build -p always -b nrf5340dk_nrf5340_cpuapp_ns  -- -DOVERLAY_CONFIG="overlay-rcp.conf $ZEPHYR_BASE/../nrf/samples/openthread/cli/overlay-thread_1_2.conf" -DCONFIG_XOROSHIRO_RANDOM_GENERATOR=y

I can't get it to build using the secure and non-secure target with the thread 1.2  overlay which appears to be required as documented here. Also, I previously tried to remove the thread 1.2 overlay using the nRF52840DK as a target and again, the coprocessor wouldn't respond.

In fact, I think that OpenThread is broken on the nrf5340 with the 1.8 release of the SDK. Just to make sure, I just pulled a fresh install and tried to build the cli sample with different CI options as listed here and in some cases I'll get a successful build but no prompt at runtime or a plain compilation failure (as is the case with the thread 1.2 overlay). That seems rather surprising given that a compilation failure should translate into a CI pipeline failure.