Datasheet

Section 7 DMA Controller (Not Supported in the H8S/2321)
Rev.6.00 Sep. 27, 2007 Page 279 of 1268
REJ09B0220-0600
7.5.8 DMAC Activation Sources
DMAC activation sources consist of internal interrupts, external requests, and auto-requests. The
activation sources that can be specified depend on the transfer mode and the channel, as shown in
table 7.12.
Table 7.12 DMAC Activation Sources
Short Address Mode Full Address Mode
Activation Source
Channels
0A and 1A
Channels
0B and 1B
Normal
Mode
Block
Transfer
Mode
Internal ADI
X
Interrupts
TXI0
X
RXI0
X
TXI1
X
RXI1
X
TGI0A
X
TGI1A
X
TGI2A
X
TGI3A
X
TGI4A
X
TGI5A
X
External DREQ pin falling edge input X
Requests
DREQ pin low-level input X
Auto-request X X
X
Legend:
: Can be specified
X : Cannot be specified
Activation by Internal Interrupt: An interrupt request selected as a DMAC activation source
can be sent simultaneously to the CPU and DTC. For details, see section 5, Interrupt Controller.
With activation by an internal interrupt, the DMAC accepts the request independently of the
interrupt controller. Consequently, interrupt controller priority settings are irrelevant.
If the DMAC is activated by a CPU interrupt source or an interrupt source that is not used as a
DTC activation source (DTA = 1), the interrupt source flag is cleared automatically by the DMA
transfer. With ADI, TXI, and RXI interrupts, however, the interrupt source flag is not cleared