151 lines
7.8 KiB
Plaintext
151 lines
7.8 KiB
Plaintext
/**
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@page SPI_FullDuplex_ComPolling SPI Full Duplex Polling example
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@verbatim
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******************************************************************************
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* @file SPI/SPI_FullDuplex_ComPolling/readme.txt
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* @author MCD Application Team
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* @brief Description of the SPI Full Duplex Polling 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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Data buffer transmission/reception between two boards via SPI using Polling mode.
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_________________________ _________________________
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| __________CN7________| |_______CN7__________ |
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| | SPI2 | | SPI2| |
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| | | | | |
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| | (pin D13) CLK(PI1)|______________________|(PI1)CLK (pin D13)| |
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| | | | | |
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| | (pin D12) MISO(PB14)|______________________|(PB14)MISO (pin D12)| |
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| | | | | |
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| | (pin D11) MOSI(PB15)|______________________|(PB15)MOSI (pin D11)| |
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| | | | | |
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| |_____________________| |____________________| |
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| __ | | |
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| |__| | | |
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| USER | | |
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| GND|______________________|GND |
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| | | |
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|_STM32F7 Master _________| |_STM32F7 Slave __________|
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HAL architecture allows user to easily change code to move to IT or DMA mode.
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To see others communication modes please check following examples:
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SPI\SPI_FullDuplex_ComDMA
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SPI\SPI_FullDuplex_ComIT
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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 216 MHz.
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The SPI peripheral configuration is ensured by the HAL_SPI_Init() function.
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This later is calling the HAL_SPI_MspInit()function which core is implementing
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the configuration of the needed SPI resources according to the used hardware (CLOCK &
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GPIO). You may update this function to change SPI configuration.
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The SPI communication is then initiated.
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The HAL_SPI_TransmitReceive() function allows the reception and the
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transmission of a predefined data buffer at the same time (Full Duplex 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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If the Master board is used, the "#define MASTER_BOARD" must be uncommented.
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If the Slave board is used the "#define MASTER_BOARD" must be commented.
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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, SPI Master starts the
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communication by sending aTxBuffer and receiving aRxBuffer through
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HAL_SPI_TransmitReceive(), at the same time SPI Slave transmits aTxBuffer
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and receives aRxBuffer through HAL_SPI_TransmitReceive().
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The end of this step is monitored through the HAL_SPI_GetState() function
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result.
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Finally, aRxBuffer and aTxBuffer are compared through Buffercmp() in order to
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check buffers correctness.
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STM32 board's LEDs can be used to monitor the transfer status:
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- LED1 turned OFF waiting User push-button to be pressed on master board.
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- LED1 turns ON if transmission/reception is complete and OK.
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- LED1 toggles slowly when there is a timeout or an error in transmission/reception process.
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@note SPIx 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 5 Seconds which means that if no communication occurs
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during 5 Seconds, a Timeout Error will be generated.
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@note You need to perform a reset on Slave board, then perform it on Master board
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to have the correct behaviour of this example.
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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 Keywords
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Connectivity, SPI, Full-duplex, Polling, Transmission, Reception, Master, Slave, MISO, MOSI
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@Note<74>If the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
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<20><><EFBFBD><EFBFBD><EFBFBD>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>The address and the size of cacheable buffers (shared between CPU and other masters) must be properly updated to be aligned to cache line size (32 bytes).
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@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Even though the user must manage the cache coherence for read accesses.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>
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@par Directory contents
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- SPI/SPI_FullDuplex_ComPolling/Inc/stm32f7xx_hal_conf.h HAL configuration file
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- SPI/SPI_FullDuplex_ComPolling/Inc/stm32f7xx_it.h SPI interrupt handlers header file
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- SPI/SPI_FullDuplex_ComPolling/Inc/main.h Header for main.c module
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- SPI/SPI_FullDuplex_ComPolling/Src/stm32f7xx_it.c SPI interrupt handlers
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- SPI/SPI_FullDuplex_ComPolling/Src/main.c Main program
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- SPI/SPI_FullDuplex_ComPolling/Src/system_stm32f7xx.c STM32F7xx system source file
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- SPI/SPI_FullDuplex_ComPolling/Src/stm32f7xx_hal_msp.c HAL MSP file
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@par Hardware and Software environment
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- This example runs on STM32F756xx/STM32F746xx devices.
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- This example has been tested with STM32746G-DISCOVERY board and can be
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easily tailored to any other supported device and development board.
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- STM32746G-DISCOVERY Set-up
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- Connect Master board PI1(CN7.D13) to Slave Board PI1(CN7.D13)
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- Connect Master board PB14(CN7.D12) to Slave Board PB14(CN7.D12)
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- Connect Master board PB15(CN7.D11) to Slave Board PB15(CN7.D11)
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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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