SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The gamma correction unit works as described in Section 13.2.4.13.2, Gamma Correction Unit. The only difference is in the input pixel format RGB30. Each component of encoded pixel value is used as a pointer to index 1 out of 1024 × 30-bit gamma curve entries in the table. Each 10-bit component is replaced with the 10-bit table value corresponding to R, G, or B component. The table is loaded by software, through the DISPC_GAMMA_TABLE2 register, and enabled via DISPC_CONFIG1[9] GAMATABLEENABLE register bit. It is possible to load only part of the table. For each write access to the table, the 30-bit gamma value is associated with bit [31] INDEX to indicate that a new table is defined. Setting bit [31] INDEX to 0x1 for the first time, resets the internal index counter. All the following accesses are considered to be for incremented index addressing in the table (bit [31] INDEX is set to 0 for each subsequent access). Figure 13-94 shows the format of one of the gamma curve values in the memory.