SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
When operating in normal mode, lower priority frames are dropped before higher priority frames. The intention is to give preference to higher priority frames. Priority 3 is the highest priority and is allowed to fill the FIFO. Priority 2 will drop packets if the packet is going to take space in the last 2k available. Priority 1 will drop packets if the packet is going to take space in the last 4k available. Priority 0 will drop packets if the packet is going to take space in the last 6k available. If fewer than 4 priorities are to be implemented then the priorities should be mapped such that the highest priorities are used. For example, if two priorities are going to be used then all packets should be mapped to priorities 3 and 2 and priorities 1 and 0 should be unused. Priority escalation may be used in normal priority mode if desired. Normal priority mode is configured as described below: