SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The overlay mechanism consists of displaying more than one layer (GFX, VID1, VID2, and VID3 layers) using:
Each pipeline (GFX, VID1, VID2, and VID3) is assigned to a single overlay and, as a consequence, to a single display controller output, LCD1, LCD2, LCD3, TV, or WB pipeline. An overlay manager can be connected to all four pipelines outputs simultaneously. The pipeline output is directed using the DISPC_GFX_ATTRIBUTES[8] CHANNELOUT bit and the DISPC_VIDp_ATTRIBUTES[31:30] CHANNELOUT2 bit field. Table 13-82 summarizes the bit field settings to direct a pipeline to an LCD/TV or WB output. The default value directs all pipelines to LCD1.
DISPC_GFX_ATTRIBUTES/DISPC_VIDp_ATTRIBUTES | ||
---|---|---|
Overlay Manager/Output | CHANNELOUT Bit | CHANNELOUT2 Bit Field |
LCD1 | 0x0 | 0x0 |
LCD2 | 0x0 | 0x1 |
LCD3 | 0x0 | 0x2 |
WB | 0x0 | 0x3 |
TV | 0x1 | 0x0 (See the following note) |
When CHANNELOUT = 0x1, the settings CHANNELOUT2 = 0x0, 0x1, 0x2, and 0x3 are reserved.
The output of each LCD overlay manager is connected to CPR block through the gamma table unit in the case of gamma correction.
When the pixel format is ARGB or RGBA, the color key match logic uses only the RGB value defined by ARGB or RGBA. The alpha blending factor is ignored.