140 lines
6.9 KiB
Plaintext
140 lines
6.9 KiB
Plaintext
/**
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@page I2C_TwoBoards_ComPolling I2C Two Boards Communication Polling Example
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file I2C/I2C_TwoBoards_ComPolling/readme.txt
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* @author MCD Application Team
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* @brief Description of the I2C 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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How to handle I2C data buffer transmission/reception between two boards,
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in polling mode.
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_________________________ _________________________
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| ______________| ___VDD____ |______________ |
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| | I2C1 | | | | I2C1| |
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| | | R (4.7K) R | | |
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| | SCL(PB6)|_____|________|_______|(PB6)SCL | |
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| | | | | | |
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| | | | | | |
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| | | | | | |
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| | SDA(PB7)|______________|_______|(PB7)SDA | |
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| | | | | |
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| |______________| |______________| |
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| __ | | __ |
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| |__| | | |__| |
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| USER GND|______________________|GND USER |
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| | | |
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|_STM32F103RB_NUCLEO______| |_STM32F103RB_NUCLEO______|
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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 64 MHz.
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The I2C peripheral configuration is ensured by the HAL_I2C_Init() function.
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This later is calling the HAL_I2C_MspInit()function which core is implementing
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the configuration of the needed I2C resources according to the used hardware (CLOCK,
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GPIO). You may update this function to change I2C configuration.
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The I2C communication is then initiated.
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The project is split in two parts: the Master Board and the Slave Board
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- Master Board
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The HAL_I2C_Master_Receive() and the HAL_I2C_Master_Transmit() functions
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allow respectively the reception and the transmission of a predefined data buffer
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in Master mode.
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- Slave Board
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The HAL_I2C_Slave_Receive() and the HAL_I2C_Slave_Transmit() functions
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allow respectively the reception and the transmission of a predefined data buffer
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in Slave mode.
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The user can choose between Master and Slave through "#define MASTER_BOARD"
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in the "main.c" file:
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- Uncomment "#define MASTER_BOARD" to select Master board.
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- Comment "#define MASTER_BOARD" to select Slave board.
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For this example the aTxBuffer is predefined and the aRxBuffer size is same as aTxBuffer.
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In a first step after the user press the User push-button on the Master Board, I2C Master
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starts the communication by sending aTxBuffer through HAL_I2C_Master_Transmit() to
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I2C Slave which receives aRxBuffer through HAL_I2C_Slave_Receive().
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The second step starts when the user press the User push-button on the Master Board,
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the I2C Slave sends aTxBuffer through HAL_I2C_Slave_Transmit()
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to the I2C Master which receives aRxBuffer through HAL_I2C_Master_Receive().
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The end of this two steps are monitored through the HAL_I2C_GetState() function
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result.
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Finally, aTxBuffer and aRxBuffer are compared through Buffercmp() in order to
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check buffers correctness.
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STM32F103RB-Nucleo's LED can be used to monitor the transfer status:
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- LED2 is ON when the transmission process is complete.
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- LED2 is OFF when the reception process is complete.
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- LED2 is slowly blinking (1 sec. period) in case of error in initialization or
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transmission/reception process
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@note I2Cx 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 Timeout is set to 10 Seconds which means that if no communication occurs
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during 10 Seconds, a Timeout Error will be generated.
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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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- I2C/I2C_TwoBoards_ComPolling/Inc/stm32f1xx_hal_conf.h HAL configuration file
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- I2C/I2C_TwoBoards_ComPolling/Inc/stm32f1xx_it.h Interrupt handlers header file
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- I2C/I2C_TwoBoards_ComPolling/Inc/main.h Header for main.c module
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- I2C/I2C_TwoBoards_ComPolling/Src/stm32f1xx_it.c Interrupt handlers
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- I2C/I2C_TwoBoards_ComPolling/Src/main.c Main program
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- I2C/I2C_TwoBoards_ComPolling/Src/system_stm32f1xx.c STM32F1xx system source file
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- I2C/I2C_TwoBoards_ComPolling/Src/stm32f1xx_hal_msp.c HAL MSP file
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@par Hardware and Software environment
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- This example runs on STM32F103xB devices.
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- This example has been tested with STM32F103RB-Nucleo board and can be
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easily tailored to any other supported device and development board.
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-STM32F103RB-Nucleo Set-up
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- Connect Master board PB6 to Slave Board PB6
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- Connect Master board PB7 to Slave Board PB7
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- Connect Master board GND to Slave Board GND
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- Check that a pull-up resistor is connected on one I2C SDA pin
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- Check that a pull-up resistor is connected on one I2C SCL pin
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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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o Uncomment "#define MASTER_BOARD" and load the project in Master Board
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o Comment "#define MASTER_BOARD" and load the project in Slave Board
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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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