This release includes:

• Added support of:

  • Nucleo L4R5ZI (thanks @Lannakin)
  • Nucleo L4R5ZI-P (thanks @Lannakin)
  • Black F407VET6 (thanks @edogaldo )
  • Blue F407VET6 Mini (thanks @edogaldo )
  • Nucleo F767ZI (thanks @davidangerls)
  • RemRam v1 (thanks @hasenbanck )
  • Nucleo L073RZ (thanks @zoomx )
  • RAK811 LoRa Tracker (Basic support) (thanks @sabas1080 )

• HAL Drivers and CMSIS updated:

  • STM32F3xx HAL Drivers to v1.5.2
  • STM32F3xx CMSIS to v2.3.3
  • STM32F7xx HAL Drivers to v1.2.6
  • STM32F7xx CMSIS to v1.2.3
  • STM32L4xx HAL Drivers to v1.9.0
  • STM32L4xx CMSIS to v1.5.0

• [F1xxx] LSI typical value is 40kHz

• Fix I2C issues raised since IT mode introduction

• Add I2C Scanner examples thanks @Testato

• WString: add toDouble (Arduino compatibility)

• [U(S)ART] Allow to use defined PIN_SERIALx_RX and PIN_SERIALx_TX in variant.h if user instantiate a hardware Serial using peripheral name.
  Example:
  HardwareSerial mySerial(USART3);
  will use PIN_SERIAL3_RX and PIN_SERIAL3_TX if defined.

• Allow use of a custom startup file:
  Syntax in the board.txt:
  xxx.build.startup_file=-DCUSTOM_STARTUP_FILE

  Example to use a custom startup file for Nucleo_L476RG:
  Nucleo_64.menu.pnum.NUCLEO_L476RG.build.startup_file=-DCUSTOM_STARTUP_FILE
  Then add a "*.S" file in the "variant/NUCLEO_L476RG/" folder
  Important note: extension must be '.S' not '.s'

  CUSTOM_STARTUP_FILE could also be defined thanks the build_opt.h.
  CMSIS_STARTUP_FILE could now be overridden using the build_opt.h, ex:
  -DCMSIS_STARTUP_FILE=\"startup_stm32l476xx.s\"

• Remove SD core dependencies. STM32SD will be able to handle properly SD detect pin and FatFs options.
  SD_DETECT_PIN pin number definition could be added in variant.h
SD_DATATIMEOUT could be redefined in variant.h

• Use define instead of enum for pins in variant.h thanks @ghent360 (Arduino compatibility)

• Fix _sbrk() to avoid user heap to override the minimum stack size

• Define _sbrk() as weak

• [Nucleo-L476RG] Fix available SRAM size

• [Nucleo-L432KC] Provide full SRAM access

• Enable FPU Single Precision (SP) for Nucleo-F303K8

• Add keywords.txt (Arduino compatibility)

• Fix std::abs() usage

• Add script to build the core thanks Travis (CI build)

• Add menu options for C RunTime library

• Change hourAM_PM_t enum member name. Required by STM32RTC library higher than 1.1.0.

• [EEPROM] Fix address capablilities

• [EEPROM] Allow FLASH definition to be redefined

• [EEPROM emulation] Rework for buffered access thanks @hasenbanck

• [U(S)ART] Fix AF settings

• Update LL wrapper files management. Move all LL wrapper file in LL/ directory instead of HAL/
  Split stm32yyxx_ll.h file per feature (stm32yyxx_ll_*.h), this allow a better granularity and to include only the required LL header file instead of the full list.

• Add built-in IWatchdog library thanks @ghent360.

• Add debug(const char *format, ...) function

• Remove GSM built-in library

• Remove UART emulation

Plus some other small fixes: See 1.3.0...1.4.0

Several components libraries are available on stm32duino organization.
They are also available through the Arduino library manager. Search for STM32duino ;)