HD64F3028F25 Datasheet, PDF (259/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

7.4.7 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 7.11.
Table 7.11 DMAC Activation Sources
Short Address Mode
Activation Source
Internal
interrupts
IMIA0
IMIA1
IMIA2
ADI
TXI0
RXI0
External
requests
Falling edge
of DREQ
Low input at
DREQ
Auto-request
Channels
0A and 1A
×
×
×
Channels
0B and 1B
×
Full Address Mode
Normal
Block
×
×
×
×
×
×
×
×
×
×
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.
Rev. 2.00, 09/03, page 227 of 890