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180 lines
9.0 KiB
Plaintext
180 lines
9.0 KiB
Plaintext
/**
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@page LTDC_Display_1Layer LTDC Display Layer 1 example
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@verbatim
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******************************************************************************
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* @file LTDC/LTDC_Display_1Layer/readme.txt
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* @author MCD Application Team
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* @brief Description of the LTDC Display 1 layer example.
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******************************************************************************
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* @attention
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*
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* <h2><center>© Copyright (c) 2018 STMicroelectronics.
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* All rights reserved.</center></h2>
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*
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* This software component is licensed by ST under BSD 3-Clause license,
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* the "License"; You may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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* opensource.org/licenses/BSD-3-Clause
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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 configure the LTDC peripheral to display a 480x272 RGB888 (24 bits/pixel)
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image on LCD using only one layer.
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In this example, the code is executed from QSPI external memory while data are in internal
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SRAM memory.
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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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After LCD initialization, the LCD layer 1 is configured to display an image
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(modelled by an array) loaded directly from flash memory by LTDC integrated DMA.
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LCD_TFT synchronous timings configuration :
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-------------------------------------------
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Total Width
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<--------------------------------------------------->
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Hsync width HBP Active Width HFP
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<---><--><--------------------------------------><-->
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____ ____|_______________________________________|____
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|___| | | |
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| | |
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__| | | |
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/|\ /|\ | | | |
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| VSYNC| | | | |
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|Width\|/ |__ | | |
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| /|\ | | | |
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| VBP | | | | |
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| \|/_____|_________|_______________________________________| |
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| /|\ | | / / / / / / / / / / / / / / / / / / / | |
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| | | |/ / / / / / / / / / / / / / / / / / / /| |
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Total | | | |/ / / / / / / / / / / / / / / / / / / /| |
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Heigh | | | |/ / / / / / / / / / / / / / / / / / / /| |
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|Active| | |/ / / / / / / / / / / / / / / / / / / /| |
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|Heigh | | |/ / / / / / Active Display Area / / / /| |
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| | | |/ / / / / / / / / / / / / / / / / / / /| |
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| | | |/ / / / / / / / / / / / / / / / / / / /| |
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| | | |/ / / / / / / / / / / / / / / / / / / /| |
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| | | |/ / / / / / / / / / / / / / / / / / / /| |
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| | | |/ / / / / / / / / / / / / / / / / / / /| |
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| \|/_____|_________|_______________________________________| |
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| /|\ | |
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| VFP | | |
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\|/ \|/_____|______________________________________________________|
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Each LCD device has its specific synchronous timings values.
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This example uses AM480272H3TMQW-T01H LCD (MB1046 B-01) and configures
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the synchronous timings as following :
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Horizontal Synchronization (Hsync) = 41
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Horizontal Back Porch (HBP) = 13
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Active Width = 480
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Horizontal Front Porch (HFP) = 32
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Vertical Synchronization (Vsync) = 10
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Vertical Back Porch (VBP) = 2
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Active Heigh = 272
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Vertical Front Porch (VFP) = 2
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LCD_TFT windowing configuration :
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---------------------------------
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To configure the active display window, this example configures the
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horizontal/vertical start and stop.
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HorizontalStart = (Offset_X + Hsync + HBP);
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HorizontalStop = (Offset_X + Hsync + HBP + Window_Width - 1);
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VarticalStart = (Offset_Y + Vsync + VBP);
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VerticalStop = (Offset_Y + Vsync + VBP + Window_Heigh - 1);
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Window_width and Window_heigh should be in line with the image size to be
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displayed.
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STM32 Discovery board's LED can be used to monitor the transfer status:
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- LED1 is ON when there is an error in Init process.
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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, LTDC, Display Controller, TFT, LCD, Graphic, RGB888, 1 Layer, BMP,
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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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- LTDC/LTDC_Display_1Layer/Inc/stm32f7xx_hal_conf.h HAL configuration file
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- LTDC/LTDC_Display_1Layer/Inc/stm32f7xx_it.h Interrupt handlers header file
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- LTDC/LTDC_Display_1Layer/Inc/main.h Main configuration file
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- LTDC/LTDC_Display_1Layer/Src/stm32f7xx_it.c Interrupt handlers
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- LTDC/LTDC_Display_1Layer/Src/main.c Main program
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- LTDC/LTDC_Display_1Layer/Src/stm32f7xx_hal_msp.c HAL MSP module
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- LTDC/LTDC_Display_1Layer/Src/system_stm32f7xx.c STM32F7xx system clock configuration file
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- LTDC/LTDC_Display_1Layer/Inc/RGB565_480x272.h Image of size 480x272 and format RGB565 to be displayed on LCD
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@par Hardware and Software environment
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- This application runs on STM32F750xx devices.
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- This application has been tested with STMicroelectronics STM32F7508-DISCO
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boards and can be easily tailored to any other supported device
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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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1. Select required configuration in memory.h in Templates\ExtMem_Boot\Inc.
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The default configuration is the right one:
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- DATA_AREA set to USE_INTERNAL_SRAM
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- CODE_AREA set to USE_QSPI
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2. Program the internal Flash with the ExtMem_Boot (see below).
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3. Program the external memory with this example "Examples\LTDC\LTDC_Display_1Layer" (see below).
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4. Start debugging user example 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 LTDC example to the external memory :
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- Open your preferred toolchain
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- Rebuild all files.
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- Run & debug the program:
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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 "N25Q128A_STM32F7508-DISCO"
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- From Erasing & Programming menu, browse and open the output binary file relative to this example
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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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* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
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*/
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