TC1796
System Units (Vol. 1 of 2)
Direct Memory Access Controller
User’s Manual 12-8 V2.0, 2007-07
DMA, V2.0
Figure 12-4 Source Address Update
The transfer count of a DMA transaction, stored in bit field CHCRmn.TREL, can also be
programmed if the DMA transaction is running. At the start of a DMA transaction, TREL
is transferred to bit field CHSRmn.TCOUNT, which is then updated during the DMA
transaction.
No reload of address or counter will be done if TCOUNT is not equal to 0.
The reprogramming of channel specific values (except for the selected address shadow
register) should be avoided while a DMA channel is active.
MCA05683
Write new source
address to (address of)
SADRmn
yes
New transaction started ?
&
(ADRCRmn.SHCT = 01
B
)
no
no
Content of SHADRmn is
transferred into
SADRmn and
SHADRmn := 00000000
H
yes
No transaction running ?
(CHSRmn.TCOUNT = 0 &
TRSR.CHmn = 0)
New source address is
directly transferred into
SADRmn
Store new source address
intermediately in
SHADRmn
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