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/**
@page USART_Communication_TxRx_DMA USART Transmitter/Receiver example (DMA mode)
@verbatim
******************************************************************************
* @file Examples_LL/USART/USART_Communication_TxRx_DMA/readme.txt
* @author MCD Application Team
* @brief Description of the USART_Communication_TxRx_DMA example.
******************************************************************************
* @attention
*
* Copyright (c) 2016 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
Configuration of GPIO and USART peripherals
to send characters asynchronously to/from an HyperTerminal (PC) in DMA mode.
This example is based on STM32F7xx USART LL API. 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.
Virtual Com port feature of STLINK is used for UART communication between board and PC.
Example execution:
After startup from reset and system configuration, LED1 is blinking quickly and wait User push-button action.
USART and DMA are configured.
On press on push button , TX DMA transfer to PC is initiated.
RX DMA transfer is also ready to retrieve characters from PC ("END" string is expected to be entered by user on PC side (HyperTerminal).
In case of both transfers successfully completed, LED1 is turned on.
In case of errors, LED1 is blinking (1sec period).
@par Keywords
Connectivity, USART, Asynchronous mode, RS-232, baud rate, DMA, HyperTerminal, Transmission
@NoteIf the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
The address and the size of cacheable buffers (shared between CPU and other masters) must be properly updated to be aligned to cache line size (32 bytes).
@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
Even though the user must manage the cache coherence for read accesses.
Please refer to the AN4838 “Managing memory protection unit (MPU) in STM32 MCUs”
Please refer to the AN4839 “Level 1 cache on STM32F7 Series”
@par Directory contents
- USART/USART_Communication_TxRx_DMA/Inc/stm32f7xx_it.h Interrupt handlers header file
- USART/USART_Communication_TxRx_DMA/Inc/main.h Header for main.c module
- USART/USART_Communication_TxRx_DMA/Inc/stm32_assert.h Template file to include assert_failed function
- USART/USART_Communication_TxRx_DMA/Src/stm32f7xx_it.c Interrupt handlers
- USART/USART_Communication_TxRx_DMA/Src/main.c Main program
- USART/USART_Communication_TxRx_DMA/Src/system_stm32f7xx.c STM32F7xx system source file
@par Hardware and Software environment
- This example runs on STM32F767xx devices.
- This example has been tested with NUCLEO-F767ZI board and can be
easily tailored to any other supported device and development board.
- NUCLEO-F767ZI Set-up
In order use of Virtual Com port feature of STLINK for connection between NUCLEO-F767ZI and PC,
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)
- 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).
- Launch the program. Press on User push button on board to initiate data transfer.
@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
*/
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