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CHAPTER 15 DMAC
Required pin input mode: edge, descriptor address: external
Required pin input mode: edge, descriptor address: internal
<Note>
The section from when a DREQn is generated to when the DM AC operation starts sho ws the
case where the DMAC operation starts first.
The DMAC operation may be delayed because the CPU fetche s instructions and accesses
data, thereby creating bus contention.
(A)
CLK
DREQn
RDXD
WRnX
#2H
#2H
S
S
#1H
#1L#1H
#1L#0L#0H
#0L#0H #2L
#2L
Data pin
Addr pin
DACK
EOP
(A)
CLK
DREQn
RDXD
WRnX
DACK
EOP
S
S
Addr pin
Data pin