TC1796
System Units (Vol. 1 of 2)
Direct Memory Access Controller
User’s Manual
12-12
V2.0, 2007-07
DMA, V2.0
The software-controlled mode that initiates a single DMA transfer to be executed is
selected for DMA channel mn by the following write operations:
•
CHCRmn.RROAT = 0
•
STREQ.SCHmn = 1, repeated for each DMA transfer
When CHCRmn.RROAT = 0, TRSR.CHmn becomes cleared after each DMA transfer of
the DMA transaction and a new software request (writing STREQ.SCHmn = 1) must be
generated for starting the next DMA transfer.
Figure 12-7 Software-controlled Mode Operation
TR0
TR1
TRn
tc-1
tc = initial transfer count
TR0
TR1
0
tc
1
0
tc
tc-1
MCT05686
TR0
TR1
TRn
tc = initial transfer count
0
tc
0
CHCRmn.RROAT = 1
CHCRmn.RROAT = 0
1
tc-1
CHSRmn.TCOUNT
DMA Transfer mn
TRSR.CHmn
INTmn
(triggered by
TCOUNT = 0)
Writing
STREQ.SCHmn = 1
CHSRmn.TCOUNT
DMA Transfer mn
TRSR.CHmn
INTmn
(triggered by
TCOUNT = 0)
Writing
STREQ.SCHmn = 1