SPRUGR9H November 2010 – April 2015 66AK2E05 , 66AK2H06 , 66AK2H12 , 66AK2H14 , 66AK2L06 , AM5K2E02 , AM5K2E04 , SM320C6678-HIREL , TMS320C6652 , TMS320C6654 , TMS320C6655 , TMS320C6657 , TMS320C6670 , TMS320C6671 , TMS320C6672 , TMS320C6674 , TMS320C6678
After an RX DMA channel has been initialized, it can begin to be used to receive packets. Packet reception involves the following steps.
When packet reception begins on a given channel, the port will begin by fetching the first descriptor (or for host packets, descriptor + buffer) from the queue manager using a free descriptor queue that was programmed into the RX flow being used by the packet. If the SOP buffer offset in the RX flow is nonzero, then the port will begin writing data after the offset number of bytes in the SOP buffer. The port will then continue filling that buffer:
The PKTDMA performs the following operations when the entire packet has been received:
The queue manager is responsible for indicating the status of the receive queues to other ports / embedded processors using out-of-band level sensitive status lines. These status lines are set anytime a queue is non-empty.
Figure 2-3 shows a diagram of the overall receive operation.