SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The DMA engine:
Each pipeline has a dedicated buffer and a channel with independent settings. Table 13-61 lists the default size and allocation of the DMA buffer. Each DMA buffer is divided into two spaces, top and bottom. Depending on the application, a DMA buffer space can be associated to a pipeline or merged with other spaces. The total number of spaces for each pipeline is from 0 (pipeline inactive) to the number of pipelines × 2 (in that case, all the DMA buffers are associated to a single pipeline). The sum of the number of spaces allocated for each pipeline must not be greater than the maximum number of available spaces. The correct number of spaces must be allocated to ensure no underflow. The spaces allocated to each pipeline must be greater than or equal to the minimum number of spaces required to support the throughput and system latency. The space assignations are done in the DISPC_GLOBAL_BUFFER register.
Pipelines | DMA Buffer Size |
---|---|
GFX | 2 lines × 640 × 128 bits |
VID1 | 2 lines × 1024 × 128 bits |
VID2 | 2 lines × 1024 × 128 bits |
VID3 | 2 lines × 1024 × 128 bits |
WB | 2 lines × 1024 × 128 bits |
Figure 13-44 is an overview of the DMA engine.