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Diffstat (limited to 'nuttx/configs/stm32f429i-disco/ltdc/README.txt')
| -rw-r--r-- | nuttx/configs/stm32f429i-disco/ltdc/README.txt | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/nuttx/configs/stm32f429i-disco/ltdc/README.txt b/nuttx/configs/stm32f429i-disco/ltdc/README.txt index d8d81d45a..4e07cea39 100644 --- a/nuttx/configs/stm32f429i-disco/ltdc/README.txt +++ b/nuttx/configs/stm32f429i-disco/ltdc/README.txt @@ -10,6 +10,49 @@ cd tools cd .. make +Note! +In the current implementation the DMA2D driver only supports clut pixel format +if the LTDC driver it does. Otherwise it will not be compatible with the nx +framework. If CONFIG_FB_CMAP is configured, nx expects that any pixel format +supports color lookup tables. This is also the case for non CLUT formats e.g. +FB_FMT_RGB16_565. This may result in wrong color representation by nx if the +pixel format is unequal to FB_FMT_RGB8. + +On the other hand layers with CLUT pixel format are not supported by the DMA2D +controller, in the case they will be used as destination layer for the following +operations: +- blit +- blend +- fillarea + +To enable clut support in both LTDC and DMA2D driver the following +configurations are valid: + +1. +- Enable LTDC_INTERFACE and LAYER1/LAYER2 +- Layer1 FB_FMT_RGB8 +- Layer2 any non clut format + +But Layer2 can only be used as destination layer for dma2d operations above. +This configuration is not compatibly to nx because LAYER2 will be referenced +by up_fbgetvplane and is an invalid CLUT pixel format. + +2. +- Enable LTDC_INTERFACE and LAYER1/LAYER2 +- Layer2 FB_FMT_RGB8 +- Layer1 any non clut format + +But Layer1 can only be used as destination layer for dma2d operations above. +This configuration should be compatibly to nx because LAYER2 will be referenced +by up_fbgetvplane and is an valid CLUT pixel format. + +All other non clut configuration work fine. + +If using the DMA2D controller without the LTDC controller e.g. camera interface +than enable CONFIG_FB_CMAP and optional CONFIG_FB_TRANSPARENCY in your board +specific configuration. + + Loading ----------------------------------------------- st-flash write nuttx.bin 0x8000000 @@ -21,3 +64,7 @@ Interaction with NSH is via the serial console at 115200 8N1 baud. From the nsh comandline execute one (or both) of the examples: - nx (default nx example) - ltdc (trivial ltdc interface test) + +Note! The ltdc example ends in an infinite loop. To get control of the nsh +start this example in the background with 'ltdc &'. + |