The v3.1.x is the long term support branch in RT-Thread. It's more focused on bug fixed and BSP update.

The following is the change log since RT-Thread v3.1.3.

Kernel

• Split the component automatic initialization to component automatic initialization and main funciton;
• Fix RT_IDLE_HOOK spelling issue;
• Add thread waiting for message queue when queue is full;
• Fix the issue of delete mq in rt_mq_create in some abnormal case;
• Remove the C++ keywords in thert_console_set_devicefunction;
• Remove the suspend_thread_count member from memory_pool structure;
• Fix the issue when block = NULL in rt_mp_free;
• Fix the issue of critical protection when rt_thread_delete change the status of thread;

Components

• Fix the issue of mPool size in C++ / Queue;
• Add the error status return in C++ / Thread task join/wait function;
• Fix compilation warning in DFS/ELM FatFS;
• Add support for Linux NFS Server in DFS/NFS;
• Fix mkfs issue in DFS/UFFS;
• Add ftruncate, flock, getuid, umask APIs;
• Fix the display issue of fd with offset in list_fd command;
• Add dfs_mount_device API to mount a file system on a device which is already in mount_table;
• Rename the C++ keywords in DFS/rename function;
• Connnect dfs/poll, select with RT_USING_POSIX in Kconfig;
• Optimize the part of the code of finsh to make it more simple;
• When RT_USING_DEVICE is not used, finsh can use the rt_hw_console_getchar() function which is simple to implement and not using the device framework;
• Increase the line length of the finsh shell to more than 256 characters;
• utest can support clang compiler and C++ compiler;
• Fix possible cross-boundary issues in ulog;
• Fix compilation warning in ulog/ulog_console_backend_output;
• Add support for file sending and receiving feature in YModem;
• CRC16 can be calculated without the lookup talbe to reduce code size in YModem component;
• Fix the issue that stack may be wrongly released during pthread/destory;
• Fix the possible memory leaks issue which caused by pthread_create abnormal case;
• The timer-related APIs under different compiler of libc are moved to the libc\compilers\common folder;
• Remove redundant definitions in dlib/sys/unistd.h (which will cause compilation warnings);
• Add sys/errno.h andsys/signal.h header files under dlib;
• Freemodbus is no longer in the kernel, and split it as a standalone softwre package;
• AT socket updated to v1.3.0:
  • Add multi-client and multi-device function support in AT Socket, and improve the dirty data handling when AT device hardware module reboot;
  • Support netdev network card feature, which can manage and control AT device network connection through the network card interface;
• Improve AT Server function support in AT components, add AT Server data sending and receiving interfaces at_server_send () and at_server_recv ();
• Fix the issue of closesocket() in SAL component when socket closing failure after shutdown();
• Improve sal_bind () network card binding related function in SAL component;
• Add IPV6 related options configuration and function support to SAL and netdev;
• Improve ping command error handling and log display in the netdev;
• Add hostname configuration options and functions in lwIP component;
• Fix the assertion issue of sys_arch_mbox_fetch() in lwIP which may occur when a socket is closed;
• Add network card uninstallation function and support for dhcpd service stop function to the lwip component;
• Fix lwIP component compilation failure caused by closing FinSH component;
• Fix the issue that the socket may not be closed during the DHCPD task in the lwIP DHCP server;
• Add dhcpd_stop() interface;
• Change log in device driver framework:
  • Refactor audio driver framework;
  • Fix the issue that the receiving length is 0 in CAN and the issue of returning wrong values;
  • Add hardware encryption and decryption driver framework;
  • Fix the flag handling issue of rt_i2c_master_send/rt_i2c_master_recv;
  • Add input capture and pulse encoding driver framework;
  • Fix the issue that partition lock is deleted when rt_mmcsd_blk_remove;
  • Fix the issue that the enumerated capacity of the large-capacity card in MMC/SD exceeded the data range;
  • When the SDIO device is initialized, the function's manufacturer and product can also use the information in CIS;
  • Improve the interrupt mode handling in the sensor framework, and fix the issue that the memory is not released when registering the sensor;
  • More information are provided in command line of sensor framework;
  • Add the checking for Rx buffer size in the serial port framework, and provide a notification when RX buffer full;
  • Remove the old Nor SPI Flash driver in SPI framework, and replace with SFUD component;
  • Fix some judgements issue in the return value of SFUD;
  • Fix the definition warning of SFUD_FLASH_DEVICE_TABLE in SFUD;
  • Add support for W25Q64DW devices in SFUD;
  • Fix FiFo creation failure handling when creating a pipe;
  • Fix the issue of releasing RBB in advance in rt_rbb_destroy() function;
  • Rename the new keyword using of C++ in rt_rbb_blk_alloc function;
  • Unify the struct rt_delayed_work in workqueue to struct rt_work;
  • Add touch driver framework;
  • Add USB Audio class;
  • Fix RNDIS plug-in/out issue in USB device stack;
  • Add the interface callback function in USB device stack;
  • Improve wlan framework, including command line functions, handling of AP name, password length, support for netdev, better configurability, etc.

BSP and CPU porting

• Add Clang compiler support in ARM-related CPU porting;
• Fix SCB_AIRCR definition issue in ARM Cortex-M0;
• Unify the .data .bss section to 8bytes alignment in GCC tool chain;
• Rerange NXP i.MXRT BSP and add related BSP documents;
• Add i.MXRT1052 ATK Commander, Fire Pro BSP and i.MXRT1064 EVK BSP to the new i.MXRT BSP;
• Fix I2C operation (master_xfer) in LPC54114-lite BSP;
• Add Audio driver in LPC54114-lite BSP;
• Refactor qemu-vexpress-a9's Audio driver and fix the issue of OS Tick accuracy;
• Remove old STM32 BSP: stm32f4xx-HAL, stm32f10x, stm32f10x-HAL, stm32f429-apollo, stm32f429-disco, stm32h743-nucleo;
• Fix the issue of rt_hw_sci_init() for opening the global interrupt in tms320f28379d BSP;
• Add support of soft I2C and hardware encryption module to WinnerMicro W60x BSP（AES/DES/3DES/RC/SHA1/MD3/CRC);
• Add oneshot WiFi configuration support in WinnerMicro W60x BSP;
• Add more STM32 BSP based on new STM32 BSP framework:
  • stm32f072-st-nucleo
  • stm32f103-gizwits-gokitv21
  • stm32f103-yf-ufun
  • stm32f412-st-nucleo
  • stm32f427-robomaster-a
  • stm32f429-st-disco
  • stm32f769-st-disco
  • stm32g431-st-nucleo
  • stm32h743-st-nucleo
  • stm32h750-armfly-h7-tool
  • stm32l4r5-st-nucleo
  • stm32l452-st-nucleo
• For the new STM32 BSP framework:
  • Add DMAMUX support to stm32l4+;
  • Update F7 HAL library SConscript;
  • Open the SWD port configuration on cubemx in stm32f103-atk-warshipv3 BSP;
  • Add support for SD card in stm32f427-robomaster-a BSP;
  • Add USBFS driver to stm32f412-nucleo BSP;
  • Remove use of device user data on uart driver;
  • Add QSPI FLASH support in stm32h743-atk-apollo BSP;
  • Optimized Ethernet driver;
  • Add hardware encryption and decryption driver;
  • Add MIPI LCD driver;
  • Add pulse encoding driver;
  • Optimize hardware timer driver;
  • Add support for UART 7/8 in serial driver;
  • Optimize WDT driver;

Tools

• Optimize scons script for eclipse in order to generate eclipse project better;
• Improve rtconfig.h generator, PATH type configuration can be generated correctly;
• Fix gcc path detection issue when using the default cross toolchain of the Linux distribution;