133 lines
6.1 KiB
Plaintext
133 lines
6.1 KiB
Plaintext
/**
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@page UART_TwoBoards_ComPolling UART TwoBoards Communication Polling example
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file UART/UART_TwoBoards_ComPolling/readme.txt
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* @author MCD Application Team
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* @brief Description of the UART Two Boards Communication Polling example.
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******************************************************************************
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* @attention
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*
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* <h2><center>© Copyright (c) 2016 STMicroelectronics.
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* All rights reserved.</center></h2>
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*
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* This software component is licensed by ST under BSD 3-Clause license,
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* the "License"; You may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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* opensource.org/licenses/BSD-3-Clause
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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 Polling mode
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between two boards.
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Board: STM32VL-Discovery (embeds a STM32F100xB device)
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Tx Pin: PA.09
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Rx Pin: PA.10
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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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|_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 polling mode a message to board 2 that sends it back to
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board 1 in polling 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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STM32VL-Discovery board LEDs are 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 LED3 is
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blinking rapidly (100 ms period).
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- When the test passes, LED4 on both boards is turned on, otherwise the test has failed.
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- When the transmission or reception process are complete, LED3 is turned on.
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- If there is an initialization or transfer error, LED3 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 24 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_ComPolling/Inc/stm32f1xx_hal_conf.h HAL configuration file
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- UART/UART_TwoBoards_ComPolling/Inc/stm32f1xx_it.h interrupt handlers header file
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- UART/UART_TwoBoards_ComPolling/Inc/main.h Header for main.c module
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- UART/UART_TwoBoards_ComPolling/Src/stm32f1xx_it.c interrupt handlers
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- UART/UART_TwoBoards_ComPolling/Src/main.c Main program
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- UART/UART_TwoBoards_ComPolling/Src/stm32f1xx_hal_msp.c HAL MSP module
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- UART/UART_TwoBoards_ComPolling/Src/system_stm32f1xx.c STM32F1xx system source file
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@par Hardware and Software environment
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- This example runs on STM32F100xB devices.
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- This example has been tested with two STM32VL-Discovery boards embedding
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a STM32F100xB device and can be easily tailored to any other supported device
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and development board.
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- STM32VL-Discovery set-up
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- Connect a wire between 1st board PA.09 pin (Uart Tx) and 2nd board PA.10 pin (Uart Rx)
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- Connect a wire between 1st board PA.10 pin (Uart Rx) and 2nd board PA.09 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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