HD6413007F20 Datasheet, PDF (256/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

7. DMA Controller
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
Activation Source
Internal
interrupts
IMIA0
IMIA1
IMIA2
ADI
TXI0
RXI0
External
requests
Falling edge
of DREQ
Low input at
DREQ
Auto-request
Short Address Mode
Channels
Channels
0A and 1A
0B and 1B
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
Yes
No
No
Full Address Mode
Normal
Block
No
Yes
No
Yes
No
Yes
No
Yes
No
No
No
No
Yes
Yes
Yes
No
Yes
No
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.
Activation by External Request: If an external request (DREQ pin) is selected as an activation
source, the DREQ pin becomes an input pin and the corresponding TEND pin becomes an output
pin, regardless of the port data direction register (DDR) settings. The DREQ input can be level-
sensitive or edge-sensitive.
Rev.5.00 Sep. 12, 2007 Page 226 of 764
REJ09B0396-0500