Figure 8-18 shows the timing when the DMAC is activated by the falling edge of
DREQ
in block
transfer mode.
Figure 8-18 Timing of DMAC Activation by Falling Edge of
DREQ
in Block Transfer Mode
ø
DREQ
RD
HWR
TEND
T
1
T
2
T
1
T
2
T
1
T
2
T
1
T
2
T
1
T
2
T
1
T
2
T
d
T
1
T
2
DMAC cycle
DMAC cycle
CPU cycle
Next sampling
Minimum 4 states
End of 1 block transfer
LWR
,
Address
bus
230
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