SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
To avoid fully occupying the FIFO with a high-priority transfer while low-priority channels wait in the arbitration queue, two separate FIFO budgets are specified: one for high-priority channels and one for low-priority channels. This is defined in the DMA4_GCR register, allowing the user to share the FIFO budget between the low- and high-priority channels. The amount of the FIFO allocated by the low- and high-priority channels is fixed by the value set in the DMA4_GCR[15:14] HI_LO_FIFO_BUDGET field. The maximum channel FIFO depth is limited by the HI_LO_FIFO_BUDGET field as follows:
If the channel is low priority:
If channel is high priority
The user must perform the following equation:
Ensure that Number of High Channel means Number of Active High-Priority Channel and that Number of Low Channel means Number of Active Low-Priority Channel.