136 lines
6.8 KiB
Plaintext
136 lines
6.8 KiB
Plaintext
/**
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@page I2C_WakeUpFromStop I2C Two Boards Communication IT Example on Stop Mode
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file I2C/I2C_WakeUpFromStop/readme.txt
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* @author MCD Application Team
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* @brief Description of the Wake Up from Stop mode example
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2016 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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How to handle I2C data buffer transmission/reception between two boards,
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using an interrupt when the device is in Stop mode.
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_________________________ _________________________
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| ______________| |______________ |
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| | I2C1 | | I2C1| |
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| | | | | |
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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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|_STM32F072RB_NUCLEO______| |_STM32F072RB_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 48 MHz. When The system is wakeup from stop mode,
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system clock is 8 Mhz. The I2C peripheral is directly clocked by HSI.
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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 and NVIC). 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_IT() and the HAL_I2C_Master_Transmit_IT() functions
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allow respectively the reception and the transmission of a predefined data buffer
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in Master mode using interrupt.
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- Slave Board
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The HAL_I2C_Slave_Receive_IT() and the HAL_I2C_Slave_Transmit_IT() functions
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allow respectively the reception and the transmission of a predefined data buffer
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in Slave mode using interrupt.
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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 presses 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_IT() to
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I2C Slave which wakes up from stop mode and receives aRxBuffer through HAL_I2C_Slave_Receive_IT().
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The second step starts when the user presses the User push-button on the Master Board,
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the I2C Slave after wake up from stop mode at address match, sends aTxBuffer through HAL_I2C_Slave_Transmit_IT()
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to the I2C Master which receives aRxBuffer through HAL_I2C_Master_Receive_IT().
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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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STM32F072RB-Nucleo RevC's LEDs can be used to monitor the transfer status on the Master Board :
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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 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_WakeUpFromStop/Inc/stm32f0xx_hal_conf.h HAL configuration file
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- I2C/I2C_WakeUpFromStop/Inc/stm32f0xx_it.h I2C interrupt handlers header file
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- I2C/I2C_WakeUpFromStop/Inc/main.h Header for main.c module
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- I2C/I2C_WakeUpFromStop/Src/stm32f0xx_it.c I2C interrupt handlers
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- I2C/I2C_WakeUpFromStop/Src/main.c Main program
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- I2C/I2C_WakeUpFromStop/Src/system_stm32f0xx.c STM32F0xx system source file
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- I2C/I2C_WakeUpFromStop/Src/stm32f0xx_hal_msp.c HAL MSP file
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@par Hardware and Software environment
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- This example runs on STM32F072RB devices.
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- This example has been tested with STM32F072RB-Nucleo RevC board and can be
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easily tailored to any other supported device and development board.
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-STM32F072RB-Nucleo RevC Set-up
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- Connect Master board PB6 to Slave Board PB6 (pin 17 on CN10)
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- Connect Master board PB7 to Slave Board PB7 (pin 21 on CN7)
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- Connect Master board GND to Slave 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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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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*/
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