HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 240

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

Figure 8-14 shows the timing when the DMAC is activated by low input at a DREQ pin. This
example shows a word-size transfer from a 16-bit two-state access area to another 16-bit two-state
access area. The DMAC continues the transfer while the DREQ pin is held low.
ø
DREQ
Address
bus
RD
HWR
TEND
,
LWR
Figure 8-14 Bus Timing of DMA Transfer Requested by Low
T
1
CPU cycle
T
2
T
3
T
d
T
1
DMAC cycle
Source
address
T
2
T
Destination
address
1
226
T
2
T
CPU cycle
1
T
2
T
d
DMAC cycle
(last transfer cycle)
T
1
Source
address
T
2
DREQ Input
T
Destination
address
1
T
2
T
CPU cycle
1
T
2