The main features are:
1. DMA2D interface
Supports the nuttx pixel formats:
- FB_FMT_RGB8
- FB_FMT_RGB24
- FB_FMT_RGB16_565
Dynamic layer allocation during runtime for the supported formats
- The number of allocatable layer can be configured.
Supported dma2d operation:
- blit (Copy content from source to destination layer) also works with
selectable area.
- blend (Blend two layer and copy the result to a destination layer wich can
be a third layer or one of the source layer) also works with selectable
area.
- fillarea (Fill a defined area of the whole layer with a specific color)
As a result of that the dma2d controller can't transfer data from the core coupled memory, CCM is disabled but usable by the ccm allocator. Currently the ccm allocator is used for allocating the layer structurei only. For the dma memory (layers frame buffer) memory is allocated from heap 2 and 3.
2. LTDC interface
I have changed the api for the currently non implemented operations:
- blit (Copy content from a dma2d layer to an ltdc layer) also works with
selectable area.
- blend (Blend two dma2d layer and copy the result to a destination ltdc
layer) also works with selectable area.
Note! ltdc layer is a layer referenced by the ltdc interface. dma2d layer
is a layer referenced by the dma2d interface.
One of the most important questions for me was, How can i flexible use an
ltdc layer with the dma2d interface, e.g. as source layer for dma2d
operations?
Get the layer id of the related dma2d layer by a special flag when using
getlid() function of the ltdc interface and use the layer id to reference
the specific dma2d layer by the dma2d interface.
The ltdc coupled dma2d layers are predefined and can't be dynamically
allocated of freed. They use the same frame buffer memory and the same
color lookup table.
Changes:
- layer internal format of the clut table
- interrupt handling for register reload (vertical vblank) instead using
waiting loop
- small fixes and refactoring
From Marco Krahl.
Gregory Nutt