Synchronization: Triggering DMA Transfers
5-21
Direct Memory Access (DMA) Controller
Another feature of this is that if the synchronization event stays active through-
out a burst, then it will be latched again following the burst. This, too, was done
for a more robust FIFO interface. This is due to the fact that the transition from
active to inactive of the FLAG can only occur during a burst. For example, if
the ‘C6202 is the reader from a FIFO, the only way for the FIFO to go from half-
full (/HF active) to less than half-full (/HF inactive) is by reading from the FIFO.
If the flag were to stay active throughout the burst, then it is known that the data
source was able to provide another set of data to the FIFO before the ‘C6202
was able to read the frame.
These new features are only used by the DMA when WSPOL, RSPOL, or
FSIG are properly configured. If all fields are left as 0 (default) the ‘C6202 DMA
functions identically to the ‘C6201 DMA.