87 lines
4.0 KiB
Plaintext
87 lines
4.0 KiB
Plaintext
/**
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@page CRC_CalculateAndCheck CRC : CRC calculation and computed CRC value checking (HAL/LL mixed usage example)
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@verbatim
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******************** (C) COPYRIGHT 2016 STMicroelectronics *******************
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* @file CRC/CRC_CalculateAndCheck/readme.txt
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* @author MCD Application Team
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* @brief Description of the CRC_CalculateAndCheck 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 use a CRC peripheral through the STM32F1xx CRC HAL & LL API
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(an LL API is used for performance improvement). A fixed CRC-32 (Ethernet)
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generator polynomial: 0x4C11DB7 is used in the CRC peripheral.
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The CRC (cyclic redundancy check) calculation unit first computes the CRC code
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of a given buffer of 32-bit data words, using HAL APIs
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In a second step, the CRC calculation unit is reset for a new CRC calculation
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and the second calculation is started using the CRC LL API. Both calculated CRC
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codes are checked against the expected value.
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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).
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The CRC peripheral configuration is ensured by HAL_CRC_Init() function.
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The latter is calling HAL_CRC_MspInit() function which core is implementing
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the configuration of the needed CRC resources according to the used hardware (CLOCK).
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For each computation, calculated CRC code is stored in uwCRCValue variable.
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Once calculated, CRC value (uwCRCValue) is compared to the CRC expected value (uwExpectedCRCValue),
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and if both checks are successful, LED is turned On.
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In case of errors, LED is blinking (1sec period).
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STM32 board LED is used to monitor the example status:
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- LED2 is ON when correct CRC values are calculated
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- LED2 is slowly blinking (1 sec. period) when there is an error in initialization or if an incorrect CRC value is calculated.
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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 Directory contents
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- CRC/CRC_CalculateAndCheck/Inc/stm32f1xx_hal_conf.h HAL configuration file
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- CRC/CRC_CalculateAndCheck/Inc/stm32f1xx_it.h Interrupt handlers header file
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- CRC/CRC_CalculateAndCheck/Inc/main.h Header for main.c module
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- CRC/CRC_CalculateAndCheck/Src/stm32f1xx_it.c Interrupt handlers
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- CRC/CRC_CalculateAndCheck/Src/main.c Main program
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- CRC/CRC_CalculateAndCheck/Src/stm32f1xx_hal_msp.c HAL MSP module
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- CRC/CRC_CalculateAndCheck/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 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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@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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*/
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