SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
Packet transmission is accomplished within the PDMA by unpacking and moving data from the Tx per-channel FIFOs which were filled via the transmit PSI-L interface to specified memory mapped address ranges via the VBUSP controller interfaces. On the Tx side of the PDMA, these transfers are always writes. Each write transfer which is performed by the Tx DMA unit is to a destination address that is hardcoded in the channel at design time and of a size as specified in the static transfer request.
The sequences of logical transactions that are performed by the PDMA on the memory interface during transmit is dependent on the channel type. The following sections describe what will happen for the two different channel types.