Description: Zephyr is a real-time operating system designed for the Internet of Things (IoT). The aim of this tutorial is to understand how to setup your environment and how to compile a Zephyr firmware. Note that Zephyr can be used with the following IoT-LAB nodes: nRF52DK, nRF52840DK, nRF51DK, BBC micro:bit, FRDM-KW41Z, Arduino Zero, ST B-L072Z-LRWAN1, ST B-L475E-IOT01A. The Zephyr SDK, which is required to build the firmwares, is provided by the SSH frontend of each IoT-LAB site.Setup your environment by cloning the iot-lab repository from GitHub
Setup your environment by cloning the iot-lab repository from GitHub
Setup Zephyr target
Setup the environment variables required to use the Zephyr SDK:
This must be done in each new shell. To have the SDK setup everytime, the command above can be added at the end of your ~/.bashrc file.
Setup the ZEPHYR_BASE environment variable:
This must be done in each new shell. To have ZEPHYR_BASE correctly setup everytime, the command above can be added at the end of your ~/.bashrc file (use an absolute path to zephyr-env.sh).
Now that everything is in place, let’s build our first hello_world firmware. This firmware is based on the sample provided in parts/zephyr/samples/hello_world. The sample will be built for the nRF52DK node, which corresponds to the board nrf52_pca10040 in Zephyr.
The generated firmware is located in the zephyr/samples/hello_world/build-nrf52/zephyr directory:
Use the *.elf file to flash the nodes using the IoT-LAB tools (webportal or cli-tools)
Here is a table containing the mapping between node names with IoT-LAB names and Zephyr names:
Build the hello_world firmware for each of the nodes listed above.
Congratulations, you have completed the tutorial! For more from FIT IOT-LAB, visit their website: https://www.iot-lab.info/
Last month, the Zephyr Project was on-site with several sessions at the Linux Foundation’s KubeCon + CloudNativeCon + Open Source Summit China. Couldn’t make it the conference? Take a look at some of the Zephyr-related content here.
Kai Ren, a Developer Relations Manager with Bluetooth SIG, shared how Bluetooth Mesh works with Zephyr. This session presented the fundamental technical concepts of Bluetooth mesh, for example, provisioning, model, security keys, publish/subscribe, address and will introduce the key points of Bluetooth mesh implementation on Zephyr project. Click here to see the presentation.
Kate Stewart, Senior Director of Strategic Programs for the Linux Foundation, presented a session about Unlocking IoT Innovation with an Open Source IoT. This presentation offered a look into the community (who is building Zephyr OS and what motivates their involvement), current initiatives (LTS release, new features and expanded functionality) and a preview of the technical roadmap (pursuing functional safety certifications and expanding our developer resources). Click here to see the presentation.
Kate also led a session about “Developing Open Source for Safety and Security.” This talk summarized the current state of Zephyr and the project’s plans for going after Functional Safety certifications in 2019 while still handling any potential security issues. This will be contrasted with the ELISA project and how the team on ELISA is working towards new processes and tools to help Linux become certified for use in functional safety applications. View the presentation here.
Wayne Ren, a Senior Software Engineer at Synopsys, will share “The Secure Design in Zephyr and its Implementation in Synopsys ARC Processor.” This talk presented the latest progress of Zephyr, the secure design of it, including memory protection and Trust Execution Environment. We will also discuss how the Zephyr is supported in Synopsys ARC processors. Watch the presentation below.
For more Zephyr-related content, we invite you to join the conversation or ask questions on our Slack channel or Mailing List.
Written by Jocelyn Li, Zephyr Community Member and Intel Zephyr Engineering Team Senior Manager
Community Participants at the 1st Open Source IoT Projects Seminar in China
The 1st Open Source IoT Projects Seminar, hosted by the Intel Corporation, was held in Shanghai at the Intel Zizhu Office from June 11 -12. As one of the host projects, Zephyr project delivered 7 technical speeches, 2 demos and 1 hands-on workshop. More than 20 people, including developers and technical managers, attended the Zephyr technical sessions. Half are community customers including China Mobile, Shenzhen DJI Tech, Neusoft, National Intelligent Sensor Innovation Center, Beijing Yuanxin Technology, OFILM, TOP CHIP and Shenzhen startup Fei Kai Te, from 7 cities in China (Shanghai, Beijing, Shenzhen, Suzhou, Chengdu, Nanjing and Wuhan).
Zephyr Speakers and Community Developers
Technical Sessions
Zephyr project overview – how developers can use the Zephyr SDK for development and debug environment set-up
Zephyr memory protection – implementations for thread isolation, stack overflow prevention and critical kernel data safekeeping
Open source and functional safety – how Zephyr is achieving the open source compatibility with safety standards
A softPLC reference solution with WebAssembly (WASM) built upon Zephyr
Utilizing the Zephyr POSIX mode to accelerate pre-silicon software development
A FW testing solution based on Zephyr test framework to accelerate the development of FW test cases
The fundamental technical concepts of Bluetooth mesh, and key points of Bluetooth mesh implementations on Zephyr project (presented by Kai Ren, Bluetooth SIG leader)
Demos
Zephyr RTOS Application Running on ACRN Hypervisor on an Intel NUC
Zephyr™ OS is being used in an increasing number of embedded use cases such as automotive and industrial where product developers benefit from the reduced cost and increase in functionality provided by running multiple operating systems on a system on a chip (SOC). This functionality allows a single piece of hardware to manage tasks of varying levels of criticality and gives product makers the full benefit of miniaturization and portability provided by multi-core SOCs. The demo shows that on top of ACRN (a lightweight hypervisor) a Clear Linux-based service operating system starts a privileged virtual machine running Zephyr OS and a standard virtual machine running another instance of Clear Linux.
Smart Badge
The demo shows smart badge with Zephyr
running on reel board. Smart badge joins a Bluetooth Mesh networking. Short
click of the button on smart badge navigates each page. Long press of the
button on “Name” page sends “Hi”.
A Full Swift Compiler and Runtime
The demo is from the startup company named
as Fei Kai Te in Shenzhen, showing a full Swift compiler and runtime that runs
on top of Zephyr. The product will be launched in August.
Workshop
Zephyr Hands-on with reel boards
The workshop provided a hands-on opportunity to set up the Zephyr SDK and customize the display on reel board.
This was the first Zephyr meetup in China. We have attracted significant attention and interest on Zephyr. Zephyr’s top 3 strengths from the community perspective are: multiple-architecture support, Bluetooth support, and Functional Safety are the top 3 strengths from community perspective. We are excited about the collaboration and discussions we had at the meetup and look forward to next meetup in China!
This newsletter covers the following inclusive commit range:
29b55f86 net: shell: Indentation fixes for ping command, merged 23 May 2019
70aa3830 net: sntp: Ignore return value from close, merged 27 June 2019
This is roughly the second month of the merge window following Zephyr v1.14 LTS. The next version of Zephyr will be version 2.0. Fancy.
The 2.0 merge window is set to close on August 9. Any new features ought to be merged (or at least posted and reviewed) before then if they’re intended for 2.0. Meanwhile, development continues apace.
A few efforts of significant interest (at least to the author) are:
a new graphical configuration tool
ongoing 64-bit support patches
the continued extraction of third-party code into separate Git repositories
big device tree changes
Graphical Interface for Kconfig
The build system now sports a guiconfig target, which can be run using e.g. west build -t guiconfig.
Here’s what it looks like:
guiconfig window
The 64-bit Project
Zephyr is currently a 32-bit only operating system. In order to support RISCV64, a wide-ranging effort to upgrade Zephyr’s kernel (and associated tests, samples, etc.) for 64-bit support is ongoing.
Maybe we’ll see RISCV128 support someday? One can dream.
Modules for Modular Modularity
With the introduction of the west tool in v1.14, Zephyr could theoretically be distributed as multiple Git repositories controlled by a manifest file, but this mechanism was largely left unused for that release.
The project is now proceeding in earnest, with several vendor HALs and other third party libraries formerly found in zephyr/ext being split into their own repositories. So far, these are repositories are all still hosted under the zephyrproject-rtos GitHub organization, so that module.yml, Kconfig, and CMakeLists.txt files can be maintained by the project. (It’s also not a bad idea for making sure the repositories stick around as long as zephyr is hosted on GitHub.)
Developers are reminded to run west update after pulling the zephyr repository in order to get any new modules added since the last time they updated.
Device Tree Changes
A variety of significant changes were merged affecting Zephyr’s use of Device Tree.
C preprocessor defines generated by device tree of the form DT_<COMPATIBLE>_<INSTANCE>_<PROPERTY> have been renamed to DT_INST_<INSTANCE>_<COMPATIBLE>_<PROPERTY>. In-tree users were updated. The old defines are now deprecated; users have an unknown amount of time to upgrade before the old defines are gone. The DT_.*_GPIO_* defines were also renamed to DT_.*_GPIOS_*.
The stringlist type was renamed to string-array to keep up with changes in upstream dtschema. The basic compatible property now has type string-array (instead of string).
There is now a concept of a “sub-node” introduced. This covers use-cases like gpio-keys, gpio-leds, pwm-leds, and other situations where the binding describes nodes lower down in the tree that contain the useful information needed by a driver. See gpio-keys.yaml and friends for examples.
The use-prop-name option for generation was removed.
It is now possible to mark aliases as deprecated.
The "ok" status was changed to "okay" for all in-tree users, again moving closer to upstream Linux behavior, but out of tree code which uses the older string should still work.
Other Interesting Happenings
As usual, a full list of merged patches broken down by area follows at the end of this post.
Architecture-specific
On x86:
The GRUB multiboot boot information structure is now preserved if available and CONFIG_X86_MULTIBOOT_INFO is enabled, and a multiboot-aware framebuffer driver was added.
Various legacy Kconfig options were removed; out of tree applications may need to remove them from their prj.conf files to avoid now-spurious warnings from kconfiglib about undefined symbols.
Prep work is being done for x64 support, but support for this processor mode is not yet finished.
On Arm:
The NXP ke1xf SoC port grew several features, including I2C, SPI, ADC, and CAN drivers.
Initial LPC5500 SoC support was added, with GPIO and USART support.
Numerous files and Kconfig options specific to STM32 were renamed as part of a general cleanup.
Zephyr’s floating point support patches for 2.0 are all merged; the new features for this release are now considered done. Support is currently x86 and Arm only.
The native_posix target now supports mapping device flash to the host file system via FUSE.
Support for various peripherals was added at SoC level; see the patch list below for details.
Bluetooth
The top-level <bluetooth/bluetooth.h> API has been extended to allow support for pairing using out-of-band data during the authentication stage. The initial customer is peripheral side support; see CONFIG_BT_OOB_DATA_FIXED.
The <bluetooth/gatt.h> API:
was incompatibly extended with support for user data pointers which will be passed to bt_gatt_complete_func_t, and
was reworked to support notifications by UUID and multiple simultaneous notifications.
The <bluetooth/l2cap.h> API added sent and status callbacks to struct bt_l2cap_chan_ops. One initial customer is the shell, as described below.
User-defined protocols are now supported. See CONFIG_BT_CTLR_USER_EXT and related code.
New shell features:
The new sent and status callbacks are used to print output when packets finish transmitting or on channel status changes.
The gatt show-db command now takes an optional second argument, which can be used to limit the number of matches that are printed.
A new gatt notify command can be used to send notifications about attribute value changes.
A new gatt discover command can be used to discover attributes; like other existing discover-foo commands, it can take a UUID, as well as start and end handles.
Development on the new “split” link layer / controller:
Random addresses are now supported for devices with hardware-based address resolution acceleration, another milestone on the walk to feature parity with the existing default controller.
A new “ticker” (or scheduler) was briefly introduced, but was reverted due to regressions related to missed advertising events.
Mesh applications can now retrieve RSSI values via mesh operation callbacks.
x86_jailhouse “board” for booting Zephyr on the Jailhouse hypervisor
quark_d2000_crb
Various boards gained new software support for peripherals, MCUboot partitions, etc; see the patch list below for details.
Build System
Support for Zephyr SDK version 0.9.5 was removed. The new recommended version is 0.10.1.
The effort to add toolchain-agnostic “intent” macros continues with the introduction of:
toolchain_cc_freestanding()
toolchain_cc_imacros()
toolchain_cc_nocommon()
toolchain_cc_cstd_flag()
toolchain_ld_force_undefined_symbols
toolchain_ld_link_elf()
In particular, the above _ld_ additions complete the linker abstraction effort.
On targets with multi-stage links, intermediate files such as the map file for zephyr_prebuilt.elf are now preserved (as zephyr_prebuilt.map, etc.) instead of being overwritten with the results of later stages. This aids debugging and improves general visibility of these build steps.
The linker scripts now support systems without flash. In this case, “ROM” regions are stored in RAM.
All modules are now built in a modules/ subdirectory of the build directory.
The previously unnamed Kconfig choice which determines the target architecture was given a name. This makes it possible to define out of tree architecture names.
Continuous Integration
A “pseudo-board” of sorts named qemu_x86_coverage was added. It exists for CI builds with code coverage measurement enabled. Previously, this area wasn’t part of CI and thus broke regularly.
The zephyrprojectrtos/ci Docker container used for CI was upgraded to Zephyr SDK 0.10.1 in version 0.7, which is now the active version.
Drivers and Device Tree
The clock control API now has clock_control_async_on() and clock_control_get_status(), for asynchronous clock management.
The USB API was substantially reworked. In particular, it has a new API for managing descriptors, and uses endpoint indexes instead of addresses. See the individual commits for more details.
The counter API now has a structure, struct counter_top_cfg, for setting up the top value of a counter. This is used in an incompatible extension to counter_set_top_value(). In-tree users were converted. The purpose of this change is to allow counter drivers as a system clock source — a long-standing effort — on hardware without alarms.
The ADC API now has a calibrate boolean in the struct adc_sequence structure used to configure a sequence of conversions. The nRF SAADC driver supports this value.
New bindings and drivers:
Skyworks SKY13351 switch bindings, used on Particle boards for antenna selection.
RISC-V CPU interrupt controller bindings
BME680 environmental sensors
TI CC13xx / C26xx SPI drivers
Pinmux driver for Microchip SoCs
Counter support for Atmel SAM0
Flash driver for the native_posix target
hwinfo support for ESP32
ili9340 display driver support for the Seeed 2.8″ TFT Touch Shield v2.0
NXP ADC12, FlexCAN, and SCG drivers
SiLabs Gecko counter driver
The console driver now supports the common logging Kconfig options. In particular, the log level is configurable with CONFIG_UART_CONSOLE_LOG_LEVEL.
The native_posix target now has device tree support. A UART and flash controller are available.
The sensor API has a SENSOR_CHAN_GAS_RES channel for gas sensor resistance.
The apds9960 driver was substantially extended. It’s now possible to disable the ambient light sensor, configure the ALS and proximity gain and proximity pulse length, and configure the proximity LED’s boost current.
Firmware Update
A follow-up Zephyr commit was merged affecting users of MCUboot with watchdog enabled, keeping up with the bootloader closing a hole which could corrupt the images if the watchdog resets while the bootloader is running.
Kernel
A new k_float_disable() system call was added, which instructs the kernel to skip floating point register handling during context switching. Applications which no longer require use of floating point registers can use it to dynamically decrease context switch overhead.
Some important bug fixes to the slab allocator and memory pool code were merged.
Threads may now call k_sleep(K_FOREVER). This is useful for threads which are explicitly woken from sleep.
The boot banner output has changed: it now distinguishes the build version obtained from Git from the kernel version string. See BUILD_VERSION.
Libraries
Support for the UpdateHub DFU service was added.
The POSIX APIs now support gethostname().
Logging
A new CONFIG_LOG_DETECT_MISSED_STRDUP (which defaults to y) was added. This option will print a message whenever the variable argument corresponding to a %s in a logging format string is neither read-only nor allocated from the pool of memory used to hold variable string data while a log message is queued.
As always, variable strings should be logged with LOG_XXX("%s", log_strdup(my_string)) — this change is meant to help catch cases where that is not happening.
There is a new os logging module, which has replaced some uses of kernel.
Miscellaneous
The shell now supports Control-N and Control-P keys to move in history. Said history was refactored to use a pool of memory for previously entered commands; this means that rather than fixing the size of history as a maximum number of commands with a fixed size, the history will store as many bytes of commands as can fit in the pool, decreasing wasted RAM. It also supports a select command which can help save typing and is similar to a command by the same name in the previous incarnation of this subsystem.
Networking
An artificial restriction on the number of instances of each LWM2M object was lifted. The number is now arbitrary.
The getaddrinfo() implementation skips DNS resolution for numeric IP addresses. It also now queries for both IPv4 and IPv6 addresses if the address family it is given is AF_UNSPEC.
The fcntl() implementation no longer is guarded by a TI-specific define; it is available whenever supported.
The precision time protocol received increased user-mode support.
A new mqtt_readall_publish_payload() API was added.
Samples
New samples:
samples/subsys/shell/fs: file system shell
samples/sensor/ti_hdc: temperature and humidity with the ti_hdc driver
samples/sensor/bme680: environmental sensor
The ili9340 sample now supports the RGB565 pixel format, and got two new Arduino shield configurations.
Storage
FAT filesystems can now be unmounted.
Mount point names can be read with fs_readmount().
Tools and Scripts
The west flash (and debug, etc.) commands can now guess the build directory. This can be useful if the build.dir-fmt configuration option is used. Users must opt in to guessing by running west config build.guess-dir runners.
This newsletter covers the following inclusive commit range:
29b55f86 net: shell: Indentation fixes for ping command, merged 23 May 2019
70aa3830 net: sntp: Ignore return value from close, merged 27 June 2019
This is roughly the second month of the merge window following Zephyr v1.14 LTS. The next version of Zephyr will be version 2.0. Fancy.
The 2.0 merge window is set to close on August 9. Any new features ought to be merged (or at least posted and reviewed) before then if they’re intended for 2.0.
Meanwhile, development continues apace.
A few efforts of significant interest (at least to the author) are:
A GUI for Kconfig
ongoing 64-bit support patches
the continued extraction of third-party code into separate Git repositories
big device tree changes
Graphical Interface for Kconfig
The build system now sports a guiconfig target, which can be run using e.g. west build -t guiconfig.
Here’s what it looks like:
The 64-bit Project
Zephyr is currently a 32-bit only operating system. In order to support RISCV64, a wide-ranging effort to upgrade Zephyr’s kernel (and associated tests, samples, etc.) for 64-bit support is ongoing.
Maybe we’ll see RISCV128 support someday? One can dream.
Modules for Modular Modularity
With the introduction of the west tool in v1.14, Zephyr could theoretically be distributed as multiple Git repositories controlled by a manifest file, but this mechanism was largely left unused for that release.
The project is now proceeding in earnest, with several vendor HALs and other third party libraries formerly found in zephyr/ext being split into their own repositories. So far, these are repositories are all still hosted under the zephyrproject-rtos GitHub organization, so that module.yml, Kconfig and CMakeLists.txt files can be maintained by the project. (It’s also not a bad idea for making sure the repositories stick around as long as zephyr is hosted on GitHub.)
Developers are reminded to run west update after pulling the zephyr repository in order to get any new modules added since the last time they updated.
Device Tree Changes
A variety of significant changes were merged affecting Zephyr’s use of Device Tree.
C preprocessor defines generated by device tree of the form DT_<COMPATIBLE>_<INSTANCE>_<PROPERTY> have been renamed to DT_INST_<INSTANCE>_<COMPATIBLE>_<PROPERTY>. In-tree users were updated. The old defines are now deprecated; users have an unknown amount of time to upgrade before the old defines are gone. The DT_.*_GPIO_* defines were also renamed to DT_.*_GPIOS_*.
THe stringlist type was renamed to string-array to keep up with changes in upstream dtschema. The basic compatible property now has type string-array (instead of string, so this isn’t truly a rename).
There is now a concept of a “sub-node” introduced. This covers use-cases like gpio-keys, gpio-leds, pwm-leds, and other situations where the binding describes nodes lower down in the tree that contain the useful information needed by a driver. See gpio-keys.yaml and friends for examples.
The use-prop-name option for generation was removed.
It is now possible to mark aliases as deprecated.
The "ok" status was changed to "okay" for all in-tree users, again moving closer to upstream Linux behavior, but out of tree code which uses the older string should still work.
Other Interesting Happenings
As usual, a full list of merged broken down by area follows at the end of this post.
Architecture-specific
On x86:
The GRUB multiboot boot information structure is now preserved if available and CONFIG_X86_MULTIBOOT_INFO is enabled, and a multiboot-aware framebuffer driver was added.
Various legacy Kconfig options were removed; out of tree applications may need to remove them from their prj.conf files to avoid now-spurious warnings from kconfiglib about undefined symbols.
Prep work is being done for x64 support, but support for this processor mode is not yet finished.
On Arm:
The NXP ke1xf SoC port grew several features, including I2C, SPI, ADC, and CAN drivers.
Initial LPC5500 SoC support was added, with GPIO and USART support.
Numerous files and Kconfig options specific to STM32 were renamed as part of a general cleanup.
Zephyr’s floating point support patches for 2.0 are all merged; the new features for this release are now considered done. Support is currently x86 and Arm only.
The native_posix target now supports mapping device flash to the host file system via FUSE.
Support for various peripherals were added at SoC level; see the patch list below for details.
Bluetooth
The top-level <bluetooth/bluetooth.h> API has been extended to allow support for pairing using out-of-band data during the authentication stage. The initial customer is peripheral side support; see CONFIG_BT_OOB_DATA_FIXED.
The <bluetooth/gatt.h> API:
was incompatibly extended with support for user data pointers which will be passed to bt_gatt_complete_func_t, and
was reworked to support notifications by UUID and multiple simultaneous notifications.
The <bluetooth/l2cap.h> API added sent and status callbacks to struct bt_l2cap_chan_opts. One initial customer is the shell, as described below.
User-defined protocols are now supported. See CONFIG_BT_CTLR_USER_EXT and related code.
New shell features:
The new sent and status callbacks are used to print output when packets finish transmitting or on channel status changes.
The gatt show-db command now takes an optional second argument, which can be used to limit the number of matches that are printed.
A new gatt notify command can be used to send notifications about attribute value changes.
A new gatt discover command can be used to discover attributes; like other existing discover-foo commands, it can take a UUID, as well as start and end handles.
Development on the new “split” link layer / controller:
Random addresses are now supported for devices with hardware-based address resolution acceleration, another milestone on the walk to feature parity with the existing default controller.
A new “ticker” (or scheduler) was briefly introduced, but was reverted due to regressions related to missed advertising events.
Mesh applications can now retrieve RSSI values via mesh operation callbacks.
x86_jailhouse “board” for booting Zephyr on the Jailhouse hypervisor
quark_d2000_crb
Various boards gained new software support for peripherals, MCUboot partitions, etc; see the patch list below for details.
Build System
Support for Zephyr SDK version 0.9.5 was removed. The new recommended version is 0.10.1.
The effort to add toolchain-agnostic “intent” macros continues with the introduction of:
toolchain_cc_freestanding()
toolchain_cc_imacros()
toolchain_cc_nocommon()
toolchain_cc_cstd_flag()
toolchain_ld_force_undefined_symbols
toolchain_ld_link_elf()
In particular, the above _ld_ additions complete the linker abstraction effort.
On targets with multi-stage links, intermediate files, such as the map file for zephyr_prebuilt.elf, are now preserved (as zephyr_prebuilt.map, etc.) instead of being overwritten with the results of later stages. This aids debugging and improves general visibility of these build steps.
The linker scripts now support systems without flash. In this case, “ROM” regions are stored in RAM.
All modules are now built in a modules/ subdirectory of the build directory.
The previously unnamed Kconfig choice which determines the target architecture was given a name. This makes it possible to define out of tree architecture names.
Continuous Integration
A “pseudo-board” of sorts named qemu_x86_coverage was added. It exists for CI builds with code coverage measurement enabled. Previously, this area wasn’t part of CI and thus broke regularly.
The zephyrprojectrtos/ci Docker container used for CI was upgraded to Zephyr SDK 0.10.1 in version 0.7, which is now the active version.
Drivers and Device Tree
The clock control API now has clock_control_async_on() and clock_controL-get_status(), for asynchronous clock management.
The USB API was substantially reworked. In particular, it has a new API for managing descriptors, and uses endpoint indexes instead of addresses. See the individual commits for more details.
The counter API now has a structure, struct counter_top_cfg, for setting up the top value of a counter. This is used in an incompatible extension to counter_set_top_value(). In-tree users were converted. The purpose of this change is to allow counter drivers as a system clock source — a long-standing effort — on hardware without alarms.
The ADC API now has a calibrate boolean in the struct adc_sequence structure used to configure a sequence of conversions. The nRF SAADC driver supports this value.
New bindings and drivers:
Skyworks SKY13351 switch bindings, used on Particle boards for antenna selection.
RISC-V CPU interrupt controller bindings
BME680 environmental sensors
TI CC13xx / C26xx SPI drivers
Pinmux driver for Microchip SoCs
Counter support for Atmel SAM0
Flash driver for the native_posix target
hwinfo support for ESP32
ili9340 display driver support for the Seeed 2.8″ TFT Touch Shield v2.0
NXP ADC12, FlexCAN, and SCG drivers
SiLabs Gecko counter driver
The console driver now supports the common logging Kconfig options. In particular, the log level is configurable with CONFIG_UART_CONSOLE_LOG_LEVEL.
The native_posix target now has device tree support. A UART and flash controller are available.
The sensor API has a SENSOR_CHAN_GAS_RES channel for gas sensor resistance.
The apds9960 driver was substantially extended. It’s now possible to disable the ambient light sensor, configure the ALS and proximity gain and proximity pulse length, and configure the proximity LED’s boost current.
Firmware Update
A follow-up Zephyr commit was merged affecting users of MCUboot with watchdog enabled, keeping up with the bootloader closing a hole which could corrupt the images if the watchdog resets while the bootloader is running.
Kernel
A new k_float_disable() system call was added, which instructs the kernel to skip floating point register handling during context switching. Applications which no longer require use of floating point registers can use it to dynamically decrease context switch overhead.
Some important bug fixes to the slab allocator and memory pool code were merged.
Threads may now call k_sleep(K_FOREVER). This is useful for threads which are explicitly woken from sleep.
The boot banner output has changed: it now distinguishes the build version obtained from Git from the kernel version string. See BUILD_VERSION.
Libraries
Support for the updatehub.io DFU service was added.
The POSIX APIs now support gethostname().
Logging
A new CONFIG_LOG_DETECT_MISSED_STRDUP (which defaults to y) was added. This option will print a message whenever the variable argument corresponding to a %s in a logging format string is neither read-only nor allocated from the pool of memory used to hold variable string data while a log message is queued.
As always, variable strings should be logged with LOG_XXX("%s", log_strdup(my_string)) — this change is meant to help catch cases where that is not happening.
There is a new os logging module, which has replaced some uses of kernel.
Miscellaneous
The shell now supports Control-N and Control-P keys to move in history. Said history was refactored to use a pool of memory for previously entered commands; this means that rather than fixing the size of history as a maximum number of commands with a fixed size, the history will store as many bytes of commands as can fit in the pool, decreasing wasted RAM. It also supports a select command which can help save typing and is similar to a command by the same name in the previous incarnation of this subsystem.
Modules
Networking
An artificial restriction on the number of instances each LWM2M object could contain was lifted. The number is now arbitrary.
The getaddrinfo() implementation skips DNS resolution for numeric IP addresses. It also now queries for both IPv4 and IPv6 addresses if the address family it is given is AF_UNSPEC.
The fcntl() implementation no longer is guarded by a TI-specific define; it is available whenever supported.
The precision time protocol received increased user-mode support.
A new mqtt_readall_publish_payload() API was added.
Samples
New samples:
samples/subsys/shell/fs: file system shell
samples/sensor/ti_hdc: temperature and humidity with the ti_hdc driver
samples/sensor/bme680: environmental sensor
The ili9340 sample now supports the RGB565 pixel format, and got two new Arduino shield configurations.
Storage
FAT filesystems can now be unmounted.
Mount point names can be read with fs_readmount().
Tools and Scripts
The west flash (and debug, etc.) commands can now guess the build directory. This can be useful if the build.dir-fmt configuration option is used. Users must opt in to guessing by running west config build.guess-dir runners.
