HD6432621 Hitachi, HD6432621 Datasheet - Page 235

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

8.3.2
The DTC operates when activated by an interrupt or by a write to DTVECR by software. An
interrupt request can be directed to the CPU or DTC, as designated by the corresponding DTCER
bit. An interrupt becomes a DTC activation source when the corresponding bit is set to 1, and a
CPU interrupt source when the bit is cleared to 0.
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 8-3 shows activation source and
DTCER clearance. The activation source flag, in the case of RXI0, for example, is the RDRF flag
of SCI0.
Table 8-3
Activation Source
Software activation The SWDTE bit is cleared to 0
Interrupt activation
Figure 8-3 shows a block diagram of activation source control. For details see section 5, Interrupt
Controller.
Activation Sources
Source flag cleared
IRQ interrupt
Activation Source and DTCER Clearance
supporting
DTVECR
On-chip
module
Figure 8-3 Block Diagram of DTC Activation Source Control
When the DISEL Bit Is 0 and
the Specified Number of
Transfers Have Not Ended
The corresponding DTCER bit
remains set to 1
The activation source flag is
cleared to 0
Interrupt
request
DTCER
Select
Clear
Interrupt controller
controller
Clear
DTC
When the DISEL Bit Is 1, or when
the Specified Number of Transfers
Have Ended
The SWDTE bit remains set to 1
An interrupt is issued to the CPU
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
Clear request
Interrupt mask
CPU
191