145 lines
6.9 KiB
Plaintext
145 lines
6.9 KiB
Plaintext
/**
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@page LibJPEG_Decoding LibJPEG decoding application
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@verbatim
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******************** (C) COPYRIGHT 2018 STMicroelectronics *******************
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* @file LibJPEG/LibJPEG_Decoding/readme.txt
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* @author MCD Application Team
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* @brief Description of the LibJPEG decoding application.
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******************************************************************************
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* @attention
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*
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* Copyright (c) 2018 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 Application Description
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This application demonstrates how to read jpeg file from USB disk memory, decode it
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and display the final BMP image on the LCD.
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In this application, the code is executed from QSPI external memory while data are in internal
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SRAM memory.
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The JPEG images should be copied at the USB disk root.
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The images must have the following properties:
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- named as "image.jpg"
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- 240*240 size
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An image under Utilities\Media\Pictures\JPG root could be used.
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Unomment "SWAP_RB" define in "main.h" file if the displayed image colors
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are inverted
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The application starts with initializing the USB MSC. Its information will be
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displayed on the LCD.
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Once the application is ready, a check on the "image.jpg" file is done. If the
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file doesn't exist, a message will be displayed and Red Led is ON.
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For each line decoded, the 240 pixels are transformed from RGB888 to RGB565 and
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then displayed.
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@note The decode is using integer method. This is recommended from speed point a view.
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The decode is faster but less accurate. The precision impact is not remarkable
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for such low resolution. In this case 240x240.
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@note If USB key is unpluged, a message will be displayed. User must plug the USB
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key and Reset the board.
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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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Display, Graphic, LibJPEG, Decoding, Flash memory, RGB565, LCD, RGB, BMP, JPG, USB disk
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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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- LibJPEG/LibJPEG_Decoding/Inc/main.h Main program header file
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- LibJPEG/LibJPEG_Decoding/Inc/stm32f7xx_it.h Interrupt handlers header file
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- LibJPEG/LibJPEG_Decoding/Inc/stm32f7xx_hal_conf.h HAL Configuration file
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- LibJPEG/LibJPEG_Decoding/Inc/ffconf.h FAT file system module configuration file
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- LibJPEG/LibJPEG_Decoding/Inc/decode.h decoder header file
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- LibJPEG/LibJPEG_Decoding/Inc/jmorecfg.h Lib JPEG configuration file (advanced configuration).
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- LibJPEG/LibJPEG_Decoding/Inc/jconfig.h Lib JPEG configuration file.
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- LibJPEG/LibJPEG_Decoding/Inc/jdata_conf.h Write/Read methods definition
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- LibJPEG/LibJPEG_Decoding/Inc/lcd_log_conf.h LCD log configuration file
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- LibJPEG/LibJPEG_Decoding/Inc/usbh_diskio.h USB diskio header file
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- LibJPEG/LibJPEG_Decoding/Inc/usbh_conf.h USB Host driver Configuration file
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- LibJPEG/LibJPEG_Decoding/Src/main.c Main program
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- LibJPEG/LibJPEG_Decoding/Src/stm32f7xx_it.c Interrupt handlers
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- LibJPEG/LibJPEG_Decoding/Src/system_stm32f7xx.c STM32F7xx system clock configuration file
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- LibJPEG/LibJPEG_Decoding/Src/decode.c decoder file
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- LibJPEG/LibJPEG_Decoding/Src/jdata_conf.c Write/Read methods definition
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- LibJPEG/LibJPEG_Decoding/Src/usbh_diskio.c USB diskio interface for FatFs
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- LibJPEG/LibJPEG_Decoding/Src/usbh_conf.c General low level driver configuration
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@par Hardware and Software environment
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- This example runs on STM32F730xx devices.
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- This example has been tested with STMicroelectronics STM32F7308-DISCO
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boards and can be easily tailored to any other supported device.
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- STM32F7308-DISCO Set-up
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- Connect a USB key to the USB HS connector (CN19).
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- USB_HS jumper should be fitted on CN8 connector.
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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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1. Select required configuration in memory.h in Templates\ExtMem_Boot\Inc.
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2. Program the internal Flash with the ExtMem_Boot (see below).
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3. Program the external QSPI memory with this application (see below).
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4. Start debugging user application or reset for free running.
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In order to load the ExtMem_Boot code :
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- Open your preferred toolchain :
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- Open the Project
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- Rebuild all files
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- Load project image
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In order to load this application to the external memory:
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- Open your preferred toolchain
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- Open the Project
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- Rebuild all files:
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- Run & debug the program:
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- For an XiP configuration (eXecute in Place from QSPI):
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- Using EWARM or MDK-ARM : Load project image from the IDE: Project->Debug
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- Using SW4STM32 :
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- Open the STM32CubeProgrammer tool
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- Select the QSPI external flash loader "MX25L512G_STM32F7308-DISCO"
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- From Erasing & Programming menu, browse and open the output binary file relative to your application
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- Load the file into the external QSPI flash using "Start Programming" at the address APPLICATION_ADDRESS (0x90000000)
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*/
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