STM32CubeF0

@verbatim
******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
* @file Examples_LL/USART/USART_WakeUpFromStop/readme.txt
* @author MCD Application Team
* @brief Description of the USART_WakeUpFromStop USART example.
******************************************************************************
* @attention
*
* <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
* All rights reserved.</center></h2>
*
* This software component is licensed by ST under BSD 3-Clause license,
* the "License"; You may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
* opensource.org/licenses/BSD-3-Clause
*
******************************************************************************
@endverbatim

@par Example Description

Configuration of GPIO and USART peripherals to allow the characters received on USART RX pin to wake up the MCU from low-power mode.
This example is based on the STM32F0xx USART LL API. The peripheral
initialization uses LL unitary service functions for optimization purposes (performance and size).

USART Peripheral is configured in asynchronous mode (9600 bauds, 8 data bit, 1 start bit, 1 stop bit, no parity).
No HW flow control is used.
USART Clock is based on HSI.

Example execution:
After startup from reset and system configuration, LED2 is blinking quickly during 3 sec,
then MCU enters Stop mode (LED2 off).
On first character reception by the USART from PC Com port (ex: using HyperTerminal)
after Stop Mode period, MCU wakes up from Stop Mode.
Received character value is checked :
- On a specific value ('S' or 's'), LED2 is turned On and program ends.
- If different from 'S' or 's', program performs a quick LED2 blinks during 3 sec and
enters again Stop mode, waiting for next character to wake up.

In case of errors, LED2 is slowly blinking (1 sec period).

@par Directory contents

- USART/USART_WakeUpFromStop/Inc/stm32f0xx_it.h Interrupt handlers header file
- USART/USART_WakeUpFromStop/Inc/main.h Header for main.c module
- USART/USART_WakeUpFromStop/Inc/stm32_assert.h Template file to include assert_failed function
- USART/USART_WakeUpFromStop/Src/stm32f0xx_it.c Interrupt handlers
- USART/USART_WakeUpFromStop/Src/main.c Main program
- USART/USART_WakeUpFromStop/Src/system_stm32f0xx.c STM32F0xx system source file

@par Hardware and Software environment

- This example runs on STM32F072xB devices.

- This example has been tested with STM32F072RB-Nucleo RevC board and can be
easily tailored to any other supported device and development board.

- STM32F072RB-Nucleo RevC Set-up
- Connect STM32 MCU board USART1 TX pin (GPIO PA9 connected to pin 21 of CN10 connector)
to PC COM port RX signal
- Connect STM32 MCU board USART1 RX pin (GPIO PA10 connected to pin 33 of CN10 connector)
to PC COM port TX signal
- Connect STM32 MCU board GND to PC COM port GND signal

@par How to use it ?

In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the example