DMA Channel Condition Determination
5-34
5.10.1 Definition of Channel Conditions
Table 5–10 describes each of the condition flags in the DMA channel second-
ary control register.
Depending on the system application, these conditions can represent errors.
The last frame condition can be used to change the reload register values for
autoinitialization. The frame index and element count reload are used every
frame. Thus, you must wait to change these values until all but the last frame
transfer in a block transfer finishes. Otherwise, the current block transfer is af-
fected.
Table 5–10. DMA Channel Condition Descriptions
COND Cleared By
Bitfield
Event
Occurs if
…
If IE Enabled
Otherwise
SX
Split transmit overrun
receive
The split operation is enabled
and transmit element transfers
get seven or more element
transfers ahead of receive ele-
ment transfers
A user write of 0 to COND
FRAME
Frame complete
After the last write transfer in
each frame is written to
memory
A user write of 0
to COND
Two CPU clocks
later
LAST
Last frame
After all counter adjustments
for the next-to-last frame in a
block transfer finish
A user write of 0
to COND
Two CPU clocks
later
WDROP
RDROP
Dropped read/write
synchronization
A subsequent synchronization
event occurs before the last
one is cleared
A user write of 0 to COND
BLOCK
Block transfer
finished
After the last write transfer in
a block transfer is written to
memory
A user write of 0
to COND
Two CPU clocks
later