STM32CubeF0

@verbatim
******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
* @file Examples_LL/USART/USART_Communication_Rx_IT/readme.txt
* @author MCD Application Team
* @brief Description of the USART_Communication_Rx_IT example.
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@endverbatim

@par Example Description

Configuration of GPIO and USART peripherals to receive characters
from an HyperTerminal (PC) in Asynchronous mode using an interrupt. The peripheral initialization
uses LL unitary service functions for optimization purposes (performance and size).

USART Peripheral is configured in asynchronous mode (115200 bauds, 8 data bit, 1 start bit, 1 stop bit, no parity).
No HW flow control is used.
GPIO associated to User push-button is linked with EXTI.
USART RX Not Empty interrupt is enabled.
Virtual Com port feature of STLINK could be used for UART communication between board and PC.

Example execution:
When character is received on USART Rx line, a RXNE interrupt occurs.
USART IRQ Handler routine is then checking received character value.
On a specific value ('S' or 's'), LED is turned On.
Received character is echoed on Tx line.
On press on push button, LED is turned Off.
In case of errors, LED is blinking.

@par Directory contents

- USART/USART_Communication_Rx_IT/Inc/stm32f0xx_it.h Interrupt handlers header file
- USART/USART_Communication_Rx_IT/Inc/main.h Header for main.c module
- USART/USART_Communication_Rx_IT/Inc/stm32_assert.h Template file to include assert_failed function
- USART/USART_Communication_Rx_IT/Src/stm32f0xx_it.c Interrupt handlers
- USART/USART_Communication_Rx_IT/Src/main.c Main program
- USART/USART_Communication_Rx_IT/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
In order to select use of Virtual Com port feature of STLINK for connection between STM32F072RB-Nucleo RevC and PC,
User has to set USE_VCP_CONNECTION define to 1 in main.h file.
If so, please ensure that USART communication between the target MCU and ST-LINK MCU is properly enabled
on HW board in order to support Virtual Com Port (Default HW SB configuration allows use of VCP)

If VCP is not used (USE_VCP_CONNECTION define set to 0 in main.h file), GPIOs connected
to USART1 TX/RX (PA.09 and PA.10) should be wired
to respectively RX and TX pins of PC UART (could be done through a USB to UART adapter).
Connect GND between STM32 board and PC UART.

- Launch serial communication SW on PC (as HyperTerminal or TeraTerm) with proper configuration
(115200 bauds, 8 bits data, 1 stop bit, no parity, no HW flow control).
Port should be selected according to USE_VCP_CONNECTION value.

- Launch the program. Enter characters on PC communication SW side.

@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