Datasheet

Table Of Contents
Section 8 Data Transfer Controller (DTC)
Page 212 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
8.3 Activation Sources
The DTC operates when activated by an interrupt or by a write to DTVECR by software. DTCER
is used to select the activation interrupt source. An interrupt request can be directed to the CPU or
DTC, as designated by the corresponding DTCER bit. At the end of a data transfer (or the last
consecutive transfer in the case of chain transfer), the activation source or corresponding DTCER
bit is cleared. Table 8.1 shows an activation source and DTCER clearance. The activation source
flag, in the case of RXI0, for example, is the RDRF flag of SCI channel 0.
When an interrupt has been designated a DTC activation source, existing CPU mask level and
interrupt controller priorities have no effect. If there is more than one activation source at the same
time, the DTC operates in accordance with the default priorities. Figure 8.2 shows a block diagram
of activation source control. For details see section 5, Interrupt Controller.
Table 8.1 Activation Source and DTCER Clearance
Activation Source
When the DISEL Bit Is 0 and the
Specified Number of Transfer
Have Not Ended
When the DISEL Bit Is 1, or when
the Specified Number of Transfers
Have Ended
Software activation The SWDTE bit is cleared to 0 The SWDTE bit remains set to 1
An interrupt is issued to the CPU
Interrupt activation The corresponding DTCER bit
remains set to 1
The activation source flag is cleared
to 0
The corresponding DTCER bit is
cleared to 0
The activation source flag remains
set to 1
A request is issued to the CPU for
the activation source interrupt