Wireless MCU Zephyr Development¶
BeaglePlay includes a Texas Instruments CC1352P7 wireless microcontroller (MCU) that can be programmed using the Linux Foundation Zephyr RTOS.
Developing directly in Zephyr will not be ultimately required for end-users who won’t touch the firmware running on the CC1352 on BeaglePlay™ and will instead use the provided wireless functionality. However, it is important for early adopters as well as people looking to extend the functionality of the open source design. If you are one of those people, this is a good place to get started.
Further, BeaglePlay is a reasonable development platform for creating Zephyr-based applications for BeagleConnect Freedom. The same Zephyr development environment setup here is also described for targeting applications on that board.
Install the latest software image for BeaglePlay¶
Note
These instructions should be generic for BeaglePlay and other boards and only the specifics of which image was used to test these instructions need be included here moving forward and the detailed instructions can be referenced elsewhere.
You may want to download and install the latest Debian Linux operating system image for BeaglePlay.
Note
These instructions were validated with the BeagleBoard.org Debian image BeaglePlay Debian 11.6 Flasher 2023-03-10.
Load this image to a microSD card using a tool like Etcher.
Insert the microSD card into BeaglePlay.
Power BeaglePlay via the USB-C connector.
Wait for the LEDs to start blinking, then turn off.
Remove power from BeaglePlay.
IMPORTANT Remove microSD card from BeaglePlay.
Apply power to BeaglePlay.
Note
This will flash the CC1352 as well as the eMMC flash on BeaglePlay.
Todo
Describe how to know it is working
Log into BeaglePlay¶
Please either plug in a keyboard, monitor and mouse or ssh
into the board. We can point
somewhere else for instructions on this. You can also point your web browser to the board to log
into the Visual Studio Code IDE environment.
Todo
A big part of what is missing here is to put your BeaglePlay on the Internet such that we can download things in later steps. That has been initially brushed over.
Flash existing IEEE 802.15.4 radio bridge (WPANUSB) firmware¶
If you’ve recieved a board fresh from the factory, this is already done and not necessary, unless you want to restore the contents back to the factory condition.
Background¶
This WPANUSB application was originally developed for radio devices with a USB interface. The CC1352P7 does not have a USB device, so the application was modified to communicate over a UART serial interface.
For the BeagleConnect Freedom, a USB-to-UART bridge device was used and the USB endpoints were made compatible with the WPANUSB linux driver which we augmented to support this board. To utilize the existing WPANUSB Zephyr application and this Linux driver, we chose to encode our UART traffic with HDLC. This has the advantage of enabing a serial console interface to the Zephyr shell while WPANUSB-specific traffic is directed to other USB endpoints.
For BeaglePlay, the USB-to-UART bridge is not used, but we largely kept the same WPANUSB application, including the HDLC encoding.
Note
Now you know why this WPAN bridge application is called WPANUSB, even though USB isn’t used!
Steps¶
Ensure the bcfserial driver isn’t blocking the serial port.
echo " fdtoverlays /overlays/k3-am625-beagleplay-bcfserial-no-firmware.dtbo" | sudo tee -a /boot/firmware/extlinux/extlinux.conf sudo shutdown -r now
Note
The default password is temppwd.
Download and flash the WPANUSB Zephyr application firmware onto the CC1352P7 on BeaglePlay from the releases on git.beagleboard.org or distros on www.beagleboard.org/distros.
debian@BeaglePlay:~$ wget https://files.beagle.cc/file/beagleboard-public-2021/images/zephyr-beagle-cc1352-0.2.2.zip debian@BeaglePlay:~$ unzip zephyr-beagle-cc1352-0.2.2.zip debian@BeaglePlay:~$ build/play/cc2538-bsl.py build/play/wpanusb
Ensure the bcfserial driver is set to load.
sudo sed -e '/bcfserial-no-firmware/ s/^#*/#/' -i /boot/firmware/extlinux/extlinux.conf sudo shutdown -r now
Verify the the 6LoWPAN network is up.
debian@BeaglePlay:~$ lsmod | grep bcfserial bcfserial 24576 0 ① mac802154 77824 2 wpanusb,bcfserial debian@BeaglePlay:~$ ifconfig SoftAp0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.8.1 netmask 255.255.255.0 broadcast 192.168.8.255 inet6 fe80::3ee4:b0ff:fe7e:b5f7 prefixlen 64 scopeid 0x20<link> ether 3c:e4:b0:7e:b5:f7 txqueuelen 1000 (Ethernet) RX packets 4046 bytes 576780 (563.2 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4953 bytes 5116336 (4.8 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 172.17.0.1 netmask 255.255.0.0 broadcast 172.17.255.255 ether 02:42:f8:29:41:69 txqueuelen 0 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 ether f4:84:4c:fc:5d:13 txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 246239 bytes 19948296 (19.0 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 246239 bytes 19948296 (19.0 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lowpan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1280 ② inet6 fe80::200:0:0:0 prefixlen 64 scopeid 0x20<link> ③ inet6 2001:db8::2 prefixlen 64 scopeid 0x0<global> ④ unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1000 (UNSPEC) RX packets 107947 bytes 6629290 (6.3 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 2882 bytes 179511 (175.3 KiB) ⑤ TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.7.2 netmask 255.255.255.0 broadcast 192.168.7.255 inet6 fe80::1eba:8cff:fea2:ed6b prefixlen 64 scopeid 0x20<link> ether 1c:ba:8c:a2:ed:6b txqueuelen 1000 (Ethernet) RX packets 9858 bytes 2638440 (2.5 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4155 bytes 1454082 (1.3 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 usb1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.6.2 netmask 255.255.255.0 broadcast 192.168.6.255 inet6 fe80::1eba:8cff:fea2:ed6d prefixlen 64 scopeid 0x20<link> ether 1c:ba:8c:a2:ed:6d txqueuelen 1000 (Ethernet) RX packets 469614 bytes 35385636 (33.7 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 365548 bytes 66523708 (63.4 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.0.161 netmask 255.255.255.0 broadcast 192.168.0.255 inet6 fe80::3ee4:b0ff:fe7e:b5f6 prefixlen 64 scopeid 0x20<link> inet6 2601:408:c083:b6c0::d00d prefixlen 128 scopeid 0x0<global> ether 3c:e4:b0:7e:b5:f6 txqueuelen 1000 (Ethernet) RX packets 3188898 bytes 678154090 (646.7 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1162074 bytes 293237366 (279.6 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 wpan0: flags=195<UP,BROADCAST,RUNNING,NOARP> mtu 123 ⑥ unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 300 (UNSPEC) RX packets 108495 bytes 2539160 (2.4 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 2888 bytes 140523 (137.2 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
① You’ll want to see that the bcfserial driver has been loaded.
② There should be a lowpan0 interface.
③ There should be a link-local address for lowpan0.
④ There should be a global address for lowpan0.
⑤ Seeing some packets have been transmitted can give you some confidence.
⑥ The wpan0 interface should be there, but we have a 6LoWPAN adapter on top of it.
Note
You may find Linux-WPAN.org useful.
Setup Zephyr development on BeaglePlay¶
Download and setup Zephyr for BeaglePlay
cd sudo apt update sudo apt install --no-install-recommends -y \ gperf \ ccache dfu-util \ libsdl2-dev \ libxml2-dev libxslt1-dev libssl-dev libjpeg62-turbo-dev libmagic1 \ libtool-bin autoconf automake libusb-1.0-0-dev \ python3-tk python3-virtualenv wget https://github.com/zephyrproject-rtos/sdk-ng/releases/download/v0.15.1/zephyr-sdk-0.15.1_linux-aarch64_minimal.tar.gz tar xf zephyr-sdk-0.15.1_linux-aarch64_minimal.tar.gz rm zephyr-sdk-0.15.1_linux-aarch64_minimal.tar.gz ./zephyr-sdk-0.15.1/setup.sh -t arm-zephyr-eabi -c west init -m https://git.beagleboard.org/beagleconnect/zephyr/zephyr --mr sdk zephyr-beagle-cc1352-sdk cd $HOME/zephyr-beagle-cc1352-sdk python3 -m virtualenv zephyr-beagle-cc1352-env echo "export ZEPHYR_TOOLCHAIN_VARIANT=zephyr" >> $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate echo "export ZEPHYR_SDK_INSTALL_DIR=$HOME/zephyr-sdk-0.15.1" >> $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate echo "export ZEPHYR_BASE=$HOME/zephyr-beagle-cc1352-sdk/zephyr" >> $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate echo 'export PATH=$HOME/zephyr-beagle-cc1352-sdk/zephyr/scripts:$PATH' >> $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate echo "export BOARD=beagleplay" >> $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate source $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate west update west zephyr-export pip3 install -r zephyr/scripts/requirements-base.txt
Activate the Zephyr build environment
If you exit and come back, you’ll need to reactivate your Zephyr build environment.
source $HOME/zephyr-beagle-cc1352-sdk/zephyr-beagle-cc1352-env/bin/activate
Verify Zephyr setup for BeaglePlay
(zephyr-beagle-cc1352-env) debian@BeaglePlay:~$ cmake --version cmake version 3.22.1 CMake suite maintained and supported by Kitware (kitware.com/cmake). (zephyr-beagle-cc1352-env) debian@BeaglePlay:~$ python3 --version Python 3.9.2 (zephyr-beagle-cc1352-env) debian@BeaglePlay:~$ dtc --version Version: DTC 1.6.0 (zephyr-beagle-cc1352-env) debian@BeaglePlay:~$ west --version West version: v0.14.0 (zephyr-beagle-cc1352-env) debian@BeaglePlay:~$ ./zephyr-sdk-0.15.1/arm-zephyr-eabi/bin/arm-zephyr-eabi-gcc --version arm-zephyr-eabi-gcc (Zephyr SDK 0.15.1) 12.1.0 Copyright (C) 2022 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Build applications for BeaglePlay CC1352¶
Now you can build various Zephyr applications
Build and flash Blinky example
cd $HOME/zephyr-beagle-cc1352-sdk/zephyr west build -d build/play_blinky samples/basic/blinky west flash -d build/play_blinky
Try out Micropython
cd git clone -b beagleplay-cc1352 https://git.beagleboard.org/beagleplay/micropython cd micropython west build -d play ports/zephyr west flash -d play tio /dev/ttyS4
Build applications for BeagleConnect Freedom¶
Build and flash Blinky example
cd $HOME/zephyr-beagle-cc1352-sdk/zephyr west build -d build/freedom_blinky -b beagleconnect_freedom samples/basic/blinky west flash -d build/freedom_blinky
Try out Micropython
cd git clone -b beagleplay-cc1352 https://git.beagleboard.org/beagleplay/micropython cd micropython west build -d freedom -b beagleconnect_freedom ports/zephyr west flash -d freedom tio /dev/ttyACM0
Important
Nothing below here is tested
Todo
west build -d build/sensortest zephyr/samples/boards/beagle_bcf/sensortest -- -DOVERLAY_CONFIG=overlay-subghz.conf
west build -d build/wpanusb modules/lib/wpanusb_bc -- -DOVERLAY_CONFIG=overlay-subghz.conf
west build -d build/bcfserial modules/lib/wpanusb_bc -- -DOVERLAY_CONFIG=overlay-bcfserial.conf -DDTC_OVERLAY_FILE=bcfserial.overlay
west build -d build/greybus modules/lib/greybus/samples/subsys/greybus/net -- -DOVERLAY_CONFIG=overlay-802154-subg.conf
Flash applications to BeagleConnect Freedom¶
And then you can flash the BeagleConnect Freedom boards over USB
- Make sure you are in Zephyr directory
cd $HOME/bcf-zephyr
- Flash Blinky
cc2538-bsl.py build/blinky
Debug applications over the serial terminal¶
Todo
Describe how to handle the serial connection