75 lines
2.0 KiB
Plaintext
75 lines
2.0 KiB
Plaintext
README.txt
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==========
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STM32F429I-DISCO LTDC Framebuffer demo example
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Configure and build
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-------------------
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cd tools
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./configure -a <appdir> stm32f429i-disco/fb
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cd ..
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make
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Note!
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In the current implementation the DMA2D driver only supports clut pixel format
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if the LTDC driver it does. Otherwise it will not be compatible with the NX
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framework. If CONFIG_FB_CMAP is configured, NX expects that any pixel format
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supports color lookup tables. This is also the case for non CLUT formats e.g.
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FB_FMT_RGB16_565. This may result in wrong color representation by NX if the
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pixel format is unequal to FB_FMT_RGB8.
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On the other hand layers with CLUT pixel format are not supported by the DMA2D
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controller, in the case they will be used as destination layer for the following
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operations:
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- blit
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- blend
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- fillarea
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To enable clut support in both LTDC and DMA2D driver the following
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configurations are valid:
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1.
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- Enable LTDC_INTERFACE and LAYER1/LAYER2
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- Layer1 FB_FMT_RGB8
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- Layer2 any non clut format
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But Layer2 can only be used as destination layer for dma2d operations above.
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This configuration is not compatibly to NX because LAYER2 will be referenced
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by up_fbgetvplane and is an invalid CLUT pixel format.
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2.
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- Enable LTDC_INTERFACE and LAYER1/LAYER2
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- Layer2 FB_FMT_RGB8
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- Layer1 any non clut format
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But Layer1 can only be used as destination layer for dma2d operations above.
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This configuration should be compatibly to NX because LAYER2 will be referenced
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by up_fbgetvplane and is an valid CLUT pixel format.
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All other non clut configuration work fine.
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If using the DMA2D controller without the LTDC controller e.g. camera interface
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than enable CONFIG_FB_CMAP and optional CONFIG_FB_TRANSPARENCY in your board
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specific configuration.
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Loading
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-------
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st-flash write nuttx.bin 0x8000000
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Executing
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---------
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The ltdc is initialized during boot up. Interaction with NSH is via the serial
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console at 115200 8N1 baud. From the nsh comandline execute the fb example:
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nsh> fb
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The test will put a pattern of concentric squares in the framebuffer and terminate.
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