SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
In ring mode, the Index (RINGACC_INDX_j) register follows the software control of the ring through the doorbell registers, while the hardware index (RINGACC_HWINDX_j) register follows the hardware access of the ring through bus transactions. It works for a ring in either direction as the doorbell register update indicates whether elements were produced or consumed. But in the other queue modes, there is no simple manner to determine which index is for software or hardware since they both use bus transactions which the module cannot differentiate. So for these other queue modes, the index register is always the read index, and the hardware index register is the write index.