SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
The UDMA keeps a transaction command scoreboard for each specific direction for the Packet Mode VBUSM Master interface. The scoreboard tracks which command indexes are currently outstanding from the DMA on that interface. When a read or write is requested by one of the internal master agents in the UDMA, the scoreboard corresponding to the specified interface and for the specified direction (read/write) is queried starting at index 0 and extending up to the maximum index for that scoreboard. The lowest index that is found and which is not currently allocated is selected and is directly used as the command ID (cid). The index values for each scoreboard. Entries are freed for re-use in a write scoreboard when write status responses are received which account for all of the outstanding write data. Entries are freed for re-use in the read scoreboard only when all data has been returned for the read.