Datasheet

Table Of Contents
Section 8 Data Transfer Controller (DTC)
Page 216 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
8.5 Operation
Register information is stored in an on-chip RAM. When activated, the DTC reads register
information in an on-chip RAM and transfers data. After the data transfer, it writes updated
register information back to the memory. Pre-storage of register information in the memory makes
it possible to transfer data over any required number of channels. The transfer mode can be
specified as normal, repeat, and block transfer mode. Setting the CHNE bit to 1 makes it possible
to perform a number of transfers with a single activation source (chain transfer).
The 24-bit SAR designates the DTC transfer source address and the 24-bit DAR designates the
transfer destination address. After each transfer, SAR and DAR are independently incremented,
decremented, or left fixed depending on its register information.
Figure 8.5 shows a flowchart of DTC operation.
Start
End
Read DTC vector
Register information read
Data transfer
Write register information
Clear an active flag
Interrupt exception
handling
Clear DTCER
CHNE = 1
Next transfer
Yes
Yes
No
Transfer
counter = 0
or DISEL = 1
No
*1
*2
Note: *1 For details on the processing that takes place, refer to the chapter on the peripheral module in question.
*2 When IRQx is the DTC activation source and the IRQ sense control registers (ISCRH and ISCRL) are
set to level sensing, the activation source flag is not cleared while IRQx is low level and DTC transfers
are performed repeatedly.
Figure 8.5 Flowchart of DTC Operation