SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
The RINGACC keeps a transaction command scoreboard for reads and writes. Each scoreboard tracks which command indexes are currently outstanding from the RINGACC and which are free to use. When a read or write is requested by the Main State Machine, the scoreboard corresponding to 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) for the outgoing transaction on the destination interface. 15 is the maximum index value 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.