r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 505

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 9 Data Transfer Controller (DTC)
9.5
Operation
The DTC stores register information in the on-chip RAM. When activated, the DTC reads register
information that is already stored in the on-chip RAM and transfers data on the basis of that
register information. After the data transfer, it writes updated register information back to the on-
chip RAM. Pre-storage of register information in the on-chip RAM makes it possible to transfer
data over any required number of channels. There are three transfer modes: normal mode, repeat
mode, and block transfer mode. Setting the CHNE bit to 1 makes it possible to perform a number
of transfers with a single activation (chain transfer). A setting can also be made to have chain
transfer performed only when the transfer counter value is 0. This enables DTC re-setting to be
performed by the DTC itself.
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.
Figure 9.5 shows a flowchart of DTC operation, and table 9.3 summarizes the chain transfer
conditions (combinations for performing the second and third transfers are omitted).
Rev. 1.00 Sep. 19, 2008 Page 475 of 1342
REJ09B0467-0100