HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 255

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

Table 8-14 Address Ranges Specifiable in MAR and IOAR
MAR
IOAR
MAR bits 23 to 20 are ignored in 1-Mbyte mode.
8.6.8 Bus Cycle when Transfer is Aborted
When a transfer is aborted by clearing the DTE bit or suspended by an NMI that clears the DTME
bit, if this halts a channel for which the DMAC has a transfer request pending internally, a dead
cycle may occur. This dead cycle does not update the halted channel’s address register or counter
value. Figure 8-27 shows an example in which an auto-requested transfer in cycle-steal mode on
channel 0 is aborted by clearing the DTE bit in channel 0.
ø
Address bus
RD
HWR, LWR
Figure 8-27 Bus Timing at Abort of DMA Transfer in Cycle-Steal Mode
1-Mbyte Mode
H'00000 to H'FFFFF
(0 to 1048575)
H'FFF00 to H'FFFFF
(1048320 to 1048575)
CPU cycle
T
1
T
2
T
d
T
1
DMAC cycle
T
2
16-Mbyte Mode
H'000000 to H'FFFFFF
(0 to 16777215)
H'FFFF00 to H'FFFFFF
(16776960 to 16777215)
T
1
241
T
2
T
1
CPU cycle
DTE bit is
cleared
T
2
T
3
T
d
DMAC
cycle
T
d
T
1
CPU cycle
T
2