
R8C/3GM Group
15. DTC
R01UH0284EJ0100 Rev.1.00
Aug 09, 2011
15. DTC
The DTC (data transfer controller) is a function that transfers data between the SFR and on-chip memory without using
the CPU. This chip incorporates one DTC channel. The DTC is activated by a peripheral function interrupt to perform
data transfers. The DTC and CPU use the same bus, and the DTC takes priority over the CPU in using the bus.
To control DTC data transfers, control data comprised of a transfer source address, a transfer destination address, and
operating modes are allocated in the DTC control data area. Each time the DTC is activated, the DTC reads control
data to perform data transfers.
15.1
Overview
i = 0 to 3, 5 to 6, j = 0 to 23
Table 15.1
DTC Specifications
Item
Specification
Activation sources
23 sources
Allocatable control data
24 sets
Address space which can be transferred
64 Kbytes (00000h to 0FFFFh)
Maximum number of transfer
times
Normal mode
256 times
Repeat mode
255 times
Maximum size of block to be
transferred
Normal mode
256 bytes
Repeat mode
255 bytes
Unit of transfers
Byte
Transfer mode
Normal mode
Transfers end on completion of the transfer causing the DTCCTj
register value to change from 1 to 0.
Repeat mode
On completion of the transfer causing the DTCCTj register value to
change from 1 to 0, the repeat area address is initialized and the
DTRLDj register value is reloaded to the DTCCTj register to continue
transfers.
Address control
Normal mode
Fixed or incremented
Repeat mode
Addresses of the area not selected as the repeat area are fixed or
incremented.
Priority of activation sources
Interrupt request
Normal mode
When the data transfer causing the DTCCTj register value to change
from 1 to 0 is performed, the activation source interrupt request is
generated for the CPU, and interrupt handling is performed on
completion of the data transfer.
Repeat mode
When the data transfer causing the DTCCTj register value to change
from 1 to 0 is performed while the RPTINT bit in the DTCCRj register
is 1 (interrupt generation enabled), the activation source interrupt
request is generated for the CPU, and interrupt handling is performed
on completion of the transfer.
Transfer start
When bits DTCENi0 to DTCENi7 in the DTCENi registers are 1
(activation enabled), data transfer is started each time the
corresponding DTC activation sources are generated.
Transfer stop
Normal mode
When bits DTCENi0 to DTCENi7 are set to 0 (activation disabled).
When the data transfer causing the DTCCTj register value to
change from 1 to 0 is completed.
Repeat mode
When bits DTCENi0 to DTCENi7 are set to 0 (activation disabled).
When the data transfer causing the DTCCTj register value to
change from 1 to 0 is completed while the RPTINT bit is 1 (interrupt
generation enabled).