SPRUIL1D May 2019 – December 2024 DRA829J , DRA829J-Q1 , DRA829V , DRA829V-Q1 , TDA4VM , TDA4VM-Q1
The AFIFO may be configured to delay making a transmit DMA request to the host until the Write FIFO has enough space for a specified number of words. In this situation, the number of transmit DMA requests to the host or DMA controller is reduced. If the Write FIFO has space to accept WNUMEVT 32-bit words, it generates a transmit DMA request to the host and then waits for a response. Once WNUMEVT words have been written to the FIFO, it checks again to see if there is space for WNUMEVT 32-bit words. If there is space, it generates another transmit DMA request to the host, and so on. In this fashion, the Write FIFO will attempt to stay filled. Note that if transmit DMA event pacing is desired, MCASP_WFIFOCTL[15-8] WNUMEVT bit field should be set to a non-zero integer multiple of the value in MCASP_WFIFOCTL[7-0] WNUMDMA bit field. If transmit DMA event pacing is not desired, then the value in MCASP_WFIFOCTL[15-8] WNUMEVT bit field should be set equal to the value in MCASP_WFIFOCTL[7-0] WNUMDMA bit field.