SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
By default, reads are as issued as fast as possible. In some cases, the reads issued by the EDMA_TPTC could fill the available command buffering for a slave, delaying other (potentially higher priority) masters from successfully submitting commands to that slave. The rate at which read commands are issued by the EDMA_TPTC is controlled by the EDMA_TPTCn_RDRATE register. The EDMA_TPTCn_RDRATE register defines the number of cycles that the EDMA_TPTC read controller waits before issuing subsequent commands for a given TR, thus minimizing the chance of the EDMA_TPTC consuming all available slave resources. The EDMA_TPTCn_RDRATE[2:0] RDRATE value must be set to a relatively small value if the transfer controller is targeted for high priority transfers and to a higher value if the transfer controller is targeted for low priority transfers.
In contrast, the Write Interface does not have any performance turning knobs because writes always have an interval between commands as write commands are submitted along with the associated write data.