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111 lines
4.9 KiB
Plaintext
111 lines
4.9 KiB
Plaintext
/**
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@page UART_TwoBoards_ComDMA UART Two Boards Communication DMA example
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@verbatim
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******************** (C) COPYRIGHT 2017 STMicroelectronics *******************
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* @file UART/UART_TwoBoards_ComDMA/readme.txt
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* @author MCD Application Team
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* @brief Description of the UART Two Boards Communication DMA example.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2017 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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This example describes an UART transmission (transmit/receive) in DMA mode
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between two boards.
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At the beginning of the main program the HAL_Init() function is called to reset
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all the peripherals, initialize the Flash interface and the systick.
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Then the SystemClock_Config() function is used to configure the system
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clock (SYSCLK) to run at 168 MHz.
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Then 1st board is waiting for user button key to be pressed. Once done, data
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are transmitted through UART2 in DMA mode. 2nd board has configured UART2
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to receive data in DMA mode. Once data received is completed, 2nd board also
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transmit same characters on UART2 which will be received by 1st board.
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Both boards compare transmitted data to received ones. If they are same, green
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led is turn on, else red one is turn On
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Warning: As both boards do not behave same way, "TRANSMITTER_BOARD" switch
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compilation exists to determine either software is for 1st transmitter board or
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2nd receiver (then transmitter) board. In other words, 1st board has to be
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flashed with software compiled with switch enable, 2nd board has to be flashed
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with software compiled with switch disable.
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STM32 discovery boards LEDs can be used to monitor the transfer status:
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- LED6 (blue) is ON when the transmission process is complete.
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- LED4 (green) is ON when the reception process is complete.
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- LED3 (Orange) is ON when there's UART error callback, otherwise the Led is blinking
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waiting for button press to start transmission.
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- LED5 (red) is ON when there is an error in transmission/reception process.
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The UART is configured as follows:
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- BaudRate = 9600 baud
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- Word Length = 8 Bits (7 data bit + 1 parity bit)
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- One Stop Bit
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- None parity
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- Hardware flow control disabled (RTS and CTS signals)
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- Reception and transmission are enabled in the time
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@note USARTx/UARTx instance used and associated resources can be updated in "main.h"
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file depending hardware configuration used.
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@note When the parity is enabled, the computed parity is inserted at the MSB
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position of the transmitted data.
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
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than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
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To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
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@note The application needs to ensure that the SysTick time base is always set to 1 millisecond
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to have correct HAL operation.
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@par Keywords
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Connectivity, UART, Baud rate, RS-232, Full-duplex, DMA, Parity, Stop bit, Transmission, Reception,
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@par Directory contents
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- UART/UART_TwoBoards_ComDMA/Inc/stm32f4xx_hal_conf.h HAL configuration file
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- UART/UART_TwoBoards_ComDMA/Inc/stm32f4xx_it.h Interrupt handlers header file
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- UART/UART_TwoBoards_ComDMA/Inc/main.h Main program header file
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- UART/UART_TwoBoards_ComDMA/Src/stm32f4xx_it.c Interrupt handlers
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- UART/UART_TwoBoards_ComDMA/Src/main.c Main program
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- UART/UART_TwoBoards_ComDMA/Src/stm32f4xx_hal_msp.c HAL MSP module
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- UART/UART_TwoBoards_ComDMA/Src/system_stm32f4xx.c STM32F4xx system clock configuration file
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@par Hardware and Software environment
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- This example runs on STM32F407xx devices.
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- This example has been tested with STMicroelectronics STM32F4-Discovery RevB & RevC
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boards and can be easily tailored to any other supported device
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and development board.
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- STM32F4-Discovery RevB & RevC set-up
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- Connect a wire between 1st board PA2 pin (UART Tx) to 2nd board PA3 pin (UART Rx)
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- Connect a wire between 1st board PA3 pin (UART Rx) to 2nd board PA2 pin (UART Tx)
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- Connect 1st board GND to 2nd Board GND
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@par How to use it ?
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In order to make the program work, you must do the following :
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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*/
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