SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Truncation logic is used to convert a pixel from ARGB 32-bit format into a lower color depth: 12- or 16-bit format based. Setting the DISPC_WB_ATTRIBUTES[10] TRUNCATIONENABLE bit to 0x1 enables the truncation to the pixel format defined by the DISPC_WB_ATTRIBUTES[4:1] FORMAT bit field. The truncation is done by removing the necessary LSB of each component to match the output format. Table 11-81 describes the truncation done on each component of the pixel.
A[7:0] | R[7:0] | G[7:0] | B[7:0] | |
---|---|---|---|---|
Output Formats | MSB LSB | MSB LSB | MSB LSB | MSB LSB |
xRGB12-4444 | Ignored | R[7:4] | G[7:4] | B[7:4] |
RGBx12-4444 | Ignored | R[7:4] | G[7:4] | B[7:4] |
RGB16-565 | Ignored | R[7:3] | G[7:2] | B[7:3] |
xRGB16-1555 | Ignored | R[7:3] | G[7:3] | B[7:3] |
ARGB16-4444 | A[7:4] | R[7:4] | G[7:4] | B[7:4] |
RGBA16-4444 | A[7:4] | R[7:4] | G[7:4] | B[7:4] |
ARGB16-1555 | A[7] | R[7:3] | G[7:3] | B[7:3] |
If there is no alpha field in the pixel format description, 0s or 1s must fill the container. 0s must be used for transparent and 1s for opaque. For example, in xRGB12 pixel format, the upper 4 bits are set to 0s because the RGB value is only 12 bits inside a 16-bit container.