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148 lines
7.4 KiB
Plaintext
148 lines
7.4 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 2016 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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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. Neither the name of STMicroelectronics nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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******************************************************************************
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@endverbatim
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@par Example Description
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UART transmission (transmit/receive) in DMA mode
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between two boards.
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Board: STM32F072RB-Nucleo RevC (embeds a STM32F072RBT6 device)
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Tx Pin: PA.09 (Pin 21 in CN10)
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Rx Pin: PA.10 (Pin 33 in CN10)
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_________________________ _________________________
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| ______________| |______________ |
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| |USART | | USART| |
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| | | | | |
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| | TX |_____________________| RX | |
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| | | | | |
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| | | | | |
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| | | | | |
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| | RX |_____________________| TX | |
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| | | | | |
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| |______________| |______________| |
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| | | |
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| GND|_____________________|GND |
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|_STM32_Board 1___________| |_STM32_Board 2___________|
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Two identical boards are connected as shown on the picture above.
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Board 1: transmitting then receiving board
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Board 2: receiving then transmitting board
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The user presses the User push-button on board 1.
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Then, board 1 sends in DMA mode a message to board 2 that sends it back to
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board 1 in DMA mode as well.
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Finally, board 1 and 2 compare the received message to that sent.
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If the messages are the same, the test passes.
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WARNING: as both boards do not behave the same way, "TRANSMITTER_BOARD" compilation
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switch is defined in /Src/main.c and must be enabled
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at compilation time before loading the executable in the board that first transmits
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then receives.
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The receiving then transmitting board needs to be loaded with an executable
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software obtained with TRANSMITTER_BOARD disabled.
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STM32F072RB-Nucleo RevC board LED is used to monitor the transfer status:
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- While board 1 is waiting for the user to press the User push-button, its LED2 is
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blinking rapidly (100 ms period).
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- While board 2 is waiting for the message from board 1, its LED2 is emitting
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a couple of flashes every half-second.
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- When the test passes, LED2 on both boards is turned on, otherwise the test has failed.
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- If there is an initialization or transfer error, LED2 is slowly blinking (1 sec. period).
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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 48 MHz.
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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 (8 data bits, no parity bit)
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- One Stop Bit
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- No 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 need 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 Directory contents
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- UART/UART_TwoBoards_ComDMA/Inc/stm32f0xx_hal_conf.h HAL configuration file
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- UART/UART_TwoBoards_ComDMA/Inc/stm32f0xx_it.h DMA interrupt handlers header file
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- UART/UART_TwoBoards_ComDMA/Inc/main.h Header for main.c module
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- UART/UART_TwoBoards_ComDMA/Src/stm32f0xx_it.c DMA interrupt handlers
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- UART/UART_TwoBoards_ComDMA/Src/main.c Main program
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- UART/UART_TwoBoards_ComDMA/Src/stm32f0xx_hal_msp.c HAL MSP module
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- UART/UART_TwoBoards_ComDMA/Src/system_stm32f0xx.c STM32F0xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F0xx devices.
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- This example has been tested with two STM32F072RB-Nucleo RevC boards embedding
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a STM32F072RBT6 device and can be easily tailored to any other supported device
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and development board.
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- STM32F072RB-Nucleo RevC set-up
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- Connect a wire between 1st board PA.09 (Pin 21 in CN10) pin (Uart Tx) and 2nd board PA.10 (Pin 33 in CN10) pin (Uart Rx)
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- Connect a wire between 1st board PA.10 (Pin 33 in CN10) pin (Uart Rx) and 2nd board PA.09 (Pin 21 in CN10) 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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* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
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*/
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