RT-Thread v3.1.1 released

This version is the second version of the v3.1.x series, and v3.1.x is also a long-term maintenance version. Starting with v4.0.0, the kernel of RT-Thread will support symmetric multi-core processors, and welcome to pay attention to the updates on GitHub.

The biggest change of this version should be the license change of source codes. Starting with this version (and later versions), the license agreement for RT-Thread will use Apache License v2.0. The submitted code and PR to RT-Thread GitHub also needs to be declared with Apache License v2.0 and sign CLA.

Apache license change has not fully covered all the codes under BSP. At present, the BSP related to ST STM32, NXP LPC/i.MXRT/Kinetis have been modified completely.

Kernel

• Support the configuration of the upward growth stack which is defined by the ARCH_CPU_STACK_GROWS_UPWARD macro. Because there are fewer ARCH for stacks growing upward, this configuration item does not display directly in menuconfig. When a CPU ARCH needs stacks growing upward, the configuration of ARCH_CPU_STACK_GROWS_UPWARD can be selected by BSP Kconfig file in default.
• Support for ARMCC V6 and later compiler (LLVM-based Compiler); currently it's mainly used in Keil MDK IDE. Please notes that the "Warnings" needs to use Moderate Warnings in project configuration in C/C++ (AC6) TAB; After using ARMCC v6, RT-Thread will add an additional CLANG_ARM macro definition; (liruncong, nongxiaoming, bernard)
• The RT_USING_IDLE_HOOK configuration in Kconfig becomes a separate configuration item, not limited to RT_USING_HOOK; (geniusgogo)

Components

• Improve the PWM driver framework and add more interfaces.
• Fix the F_SETFL handling in ioctrl function; Fix the return value issue of fcntl function which is always 0 value.
• Fix the memheap object type issue when creating a ramfs object.
• Add power management framework for low power applications.
• Add multi-segment support for read and write operations in MC/SDIO driver framework (for stm32, you can choose a separate stm32_sdio package); (weety)
• Add ringblk_buf component for the block mode but in ringbuffer applications;
• Improve WLAN management framework with unified interfaces, management, commands, to provide more friendly support to developers and users;
• Add the conditional macro in the finsh when the MSH component is not enabled, even if the code files are compiled.
• Remove gdbstub and move to rt-thread packages.
• Upgrade and improve SAL and AT components: (linuxhan, eddylin83, slyant, luofanlu, Hubert Xie, Lawlieta, zhaojuntao, armink)
  • Fix the none cleared issue when closing socket in SAL, which lead to the socket is always holding.
  • Fix the issue that select() could not be used normally for UDP communication in AT component. Add the receiving data handling to complete the clearing of received event;
  • Add the errno value when receive data timeout in at_recvfrom function in the AT component.
  • Add the receive data timeout handling in at_client_recv function in the AT component.
• Fix a possible issue in fputc function implementation when using microlib;
• Add gmtime_r implementation for ARMCC, IAR tool chain;
• Improve time function support in IAR and support 64bit time; (hichard)
• DHCPD's support for IPv6;
• Remove lwIP-1.3.2 porting and add lwIP-2.1.0 porting; lwIP-2.0.2 is still the default version.
• Add a lightweight ulog component and automatically replace the debug macro of the original rtdbg.h when it's enable.
• USB stack update
  • HOST, optimize the USB HOST timeout mechanism; fix the un-alignment visit issue in F4xx-HAL USB host driver;
  • Device: Add the check when class drivers are illegally registered; Fix the un-aligned access issue in some platforms; optimize CDC VCOM classes, add the timeout mechanism and ID definition.

BSP

• Upgrade the wlan adapter to the new version of Wi-Fi management framework in amebaz BSP.
• Add airkiss wifi configuration code to amebaz BSP.
• Update Apollo2 BSP with ADC, GPIO, I2C, PDM, SPI, UART and other drivers; (Haleyl)
• BeagleBone BSP is changed to main function mode, and adds Kconfig configuration file.
• DM365 BSP adds Kconfig configuration file;
• Update HiFive1 BSP and add more documentation.
• Update imx6sx BSP to main function mode, and add Kconfig configuration file.
• Change the old imxrt1052-evk BSP. The imxrt1052-related BSPs are classified into the bsp/imxrt directory; A touch framework is added to bsp/imxrt, and later will be moved into components/drivers directory;
• Improve stm32f4xx-HAL BSP with PWM, I2C, USB Host driver; (XuanZe, xuzhuoyi)
• Improve stm32f10x BSP with CAN driver and increase I2C driver; (wuhanstudio, AubrCool)
• Improve stm32f10x-HAL BSP with I2C, IWG, PWM, RTC and other drivers, improve UART driver; (XuanZe)
• Improve stm32f429-disco BSP and add I2C, LCD, Touch driver; (xuzhuoyi)
• Improve x86 BSP, support dlmodule function; (SASANO Takayoshi, parai)

Tool

• Modify the building script to support Python 3; <Python 3 patches have been submitted to scons and need to wait for next scons release，maybe scons-3.0.2> (Arda)
• Add scons --pyconfig mode, which has a TK UI configurator; (weety)
• Support for GNU GCC 7/8 version toolchains (The -std=c99 is not added into C-compiler flags), but please note: PThreads component failed in 2.5 and new version of newlib.