Texas Instruments TMS320C6201 Reference Manual page 116

Split-Channel Operation
5.8 Split-Channel Operation
5.8.1 Split DMA Operation
5-28
Split-channel operation allows a single DMA channel to service both the input
(receive) and output (transmit) streams from an external or internal peripheral
with a fixed address.
Split-channel operation consists of transmit element transfers and receive ele-
ment transfers. In turn, these transfers each consist of a read and a write trans-
fer:
Transmit element transfer
J
Transmit read transfer: Data is read from the DMA channel source ad-
dress. The source address is then adjusted as configured. The transfer
count is then decremented. This event is not synchronized.
J
Transmit write transfer: Data from the transmit read transfer is written to
the split destination address. This event is synchronized as indicated by
the WSYNC field. The DMA channel keeps track internally of the num-
ber of pending receive transfers.
Receive element transfer
J
Receive read transfer: Data is read from the split source address. This
event is synchronized as indicated by the RSYNC field.
J
Receive write transfer: Data from the receive read transfer is written to
the destination address. The destination address is then adjusted as
configured. This event is not synchronized.
Because only a single element count and frame count exists per channel, the
element count and the frame count are the same for both the received and the
transmitted data. For split-channel operation to work properly, both the
RSYNC and WSYNC fields must be set to non-zero synchronization events.
Also, frame synchronization must be disabled in split-channel operation.