189 lines
9.4 KiB
Plaintext
189 lines
9.4 KiB
Plaintext
/**
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@page SPI_FullDuplex_AdvComIT SPI Full Duplex Polling example
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@verbatim
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******************************************************************************
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* @file SPI/SPI_FullDuplex_AdvComIT/readme.txt
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* @author MCD Application Team
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* @brief Description of the SPI Full Duplex IT 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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Configuration of the HAL SPI API to transmit/receive a data buffer using Interrupt mode
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in an advanced communication mode:
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The master board always sends the command to the slave before performing any transmission;
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the slave board sends back an acknowledgement before proceeding.
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- Hardware Description
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To use this example, you need to load it on two STM32 boards (let's call them
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BoardA and BoardB) then connect these two boards through SPI lines and GND.
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In the firmware example two project are provided to use the SPI peripheral as STM32
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Master device or as STM32 Slave .
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_________________________ _________________________
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| ______________| |______________ |
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| |SPI1 | | SPI1 | |
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| | | | | |
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| | CLK(PB3) |______________________|(PB3)CLK CN7.15 | |
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| | | | | |
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| | MISO(PA6)|______________________|(PA6)MISO CN7.D12 | |
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| | | | | |
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| | MOSI(PA7)|______________________|(PA7)MOSI CN7.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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@note The connection between the pins should use a short wires and a common Ground.
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- Software Description
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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 100 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 and NVIC). You may update this function to change SPI configuration.
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The SPI peripheral is configured in full duplex mode with baudrate = FCPU/256.
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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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In Master board, when the user button is pressed (used for only synchronization at startup)
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these steps are executed:
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- Synchro with the Slave
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- Requests read operation by sending specific command to the slave that contain
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the master read command and the number of data to be read
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- Synchro with the Slave
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- Receive the ACK from the Slave
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- Synchro with the Slave
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- Receive the requested data "aRxBuffer" from the slave
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- Synchro with the Slave
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- Send the ACK to the Slave
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- Checks the correctness of data and in case of mismatch between sent and received data,
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LED2 is On and communication is stopped (using infinite loop). Otherwise LED3 is Toggle
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indicate that the data is received correctly.
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- Synchro with the Slave
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- Requests write operation by sending specific command to the slave that contain
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the master write command and the number of data to be written
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- Synchro with the Slave
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- Receive the ACK from the Slave
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- Synchro with the Slave
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- Send the requested data "aTxMasterBuffer" to the slave
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- Synchro with the Slave
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- Receive the ACK from the Slave
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These previously steps are repeated in an infinitely loop and a delay 100ms is inserted at
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the end of data transfer to permit the user to see LED1 toggling.
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In Slave board, these steps are executed:
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- Synchro with the Master
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- Receive requests from the master
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- Synchro with the Master
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- Send the ACK to the Master
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- Synchro with the Master
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- If the "ADDRCMD_MASTER_READ" command is received:
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- Send the requested data "aTxSlaveBuffer" to the Master
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- Synchro with the Master
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- Receive the ACK from the Master
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- If the "ADDRCMD_MASTER_WRITE" command is received:
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- Receive the requested data "aRxBuffer" from the Master
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- Synchro with the Master
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- Send the ACK to the Master
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- checks the correctness of data is performed and in case of mismatch between sent and
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received data, LED2 is On and communication is stopped (using infinite loop).
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Otherwise LED3 Toggles indicating that the data is received correctly.
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These previously steps are repeated in an infinitely loop.
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STM32F7-Nucleo board's LEDs can be used to monitor the transfer status:
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- LED1 (green) toggles on Master board waiting for user button to be pushed.
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- LED1 (green) toggles on Master board at end of each loop.
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- LED2 (blue) toggles on both boards when the read comparison is OK.
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- LED3 (red) turns ON when there is 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 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 needs 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, Interrupt, Transmission, Reception, Master, Slave, MISO, MOSI,
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Command, acknowledge
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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_AdvComIT/Inc/stm32f7xx_hal_conf.h HAL configuration file
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- SPI/SPI_FullDuplex_AdvComIT/Inc/stm32f7xx_it.h SPI interrupt handlers header file
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- SPI/SPI_FullDuplex_AdvComIT/Inc/main.h Main program header file
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- SPI/SPI_FullDuplex_AdvComIT/Src/stm32f7xx_it.c SPI interrupt handlers
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- SPI/SPI_FullDuplex_AdvComIT/Src/main.c Main program
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- SPI/SPI_FullDuplex_AdvComIT/Src/system_stm32f7xx.c STM32F7xx system clock configuration file
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- SPI/SPI_FullDuplex_AdvComIT/Src/stm32f7xx_hal_msp.c HAL MSP module
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@par Hardware and Software environment
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- This example runs on STM32F767ZI devices.
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- This example has been tested with NUCLEO-F767ZI Rev B board and can be
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easily tailored to any other supported device and development board.
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- NUCLEO-F767ZI Rev B Set-up
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- Use LED1, LED2 and LED3 connected respectively to PA.5, PB.7, PB.14
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- Use the User Push Button
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- Connect Master board PB3 to Slave Board PB3 (Stuino CN7, pin 15)
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- Connect Master board PA6 to Slave Board PA6 (Arduino D12)
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- Connect Master board PA7 to Slave Board PA7 (Arduino 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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