Datasheet

Table Of Contents
Section 7 DMA Controller (DMAC)
REJ09B0140-0900 Rev. 9.00 Page 189 of 846
Sep 16, 2010
H8S/2215 Group
7.4.7 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, as shown in table 7.8.
Table 7.8 DMAC Activation Sources
Full Address Mode
Activation
Source
Short Address
Mode
Normal Mode
Block Transfer
Mode
ADI × Internal
interrupt
TXI0
×
RXI0 ×
TXI1 ×
RXI1 ×
TGI0A ×
TGI1A ×
TGI2A ×
USB request Low level input of the DERQ
signal
× ×
Auto-request × ×
Legend:
: Can be specified
×: 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 not accepted.
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
unless the prescribed register is accessed in a DMA transfer. If the same interrupt is used as an
activation source for more than one channel, the interrupt request flag is cleared when the highest-
priority channel is activated first. Transfer requests for other channels are held pending in the
DMAC, and activation is carried out in order of priority.