[Updated on OS6] TimerEvent is no longer existing!! Checked TimerEvent function on os5 latest version. Result is okay on FRDM-K64F but STM32 series are NOT okay e.g. Nucleo-L152RE, -F446RE, -L432KC and so on. This TimerEvent is using SoftSerial library and works well on old os2 but not OS5 latest version STM32 series Mbed board.