SPRUIV7B May 2022 – September 2023 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
This section describes the setup procedure for Tx channels within the PKTDMA. After a reset or a previous teardown operation but before queuing packets to a channel the host must initialize the channel’s Tx Port DMA State. The host initializes the channel Tx Port DMA State by configuring all of the Tx flow entries for the channel and then writing to the Tx Channel Configuration Register A (TCHAN[a]_TCFG). The Host may choose to write the enable bit in the Tx Channel Configuration Register A (TCHAN[a]_TCFG) at the same time or after it has written all of the channel parameters but note that every write to the Tx Channel Configuration Registers will overwrite the channel state for all bytes that are enabled for the write transaction.
After a Transmit channel has been set up, packets can be added to the Queues for the channel to begin the transmit operation. The following sections describe how the transmit operations are performed for the various descriptor types.