HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 237

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

8.4.7 DMAC Activation
The DMAC can be activated by an internal interrupt, external request, or auto-request. The
available activation sources differ depending on the transfer mode and channel as indicated in
table 8-11.
Table 8-11 DMAC Activation Sources
Activation Source
Internal
interrupts
External
requests
Auto-request
Activation by Internal Interrupts: When an interrupt request is selected as a DMAC activation
source and the DTE bit is set to 1, that interrupt request is not sent to the CPU. It is not possible
for an interrupt request to activate the DMAC and simultaneously generate a CPU interrupt.
When the DMAC is activated by an interrupt request, the interrupt request flag is cleared
automatically. If the same interrupt is selected to activate two or more channels, the interrupt
request flag is cleared when the highest-priority channel is activated, but the transfer request is
held pending on the other channels in the DMAC, which are activated in their priority order.
IMIA0
IMIA1
IMIA2
IMIA3
TXI0
RXI0
Falling edge
of DREQ
Low input at
DREQ
Channels
0A and 1A
Short Address Mode
223
Channels
0B and 1B
Normal
Full Address Mode
Block