User's Manual

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 399 of 1852
Nov 30, 2020
RX23W Group 19. Data Transfer Controller (DTCa)
19.4 Operation
The DTC transfers data in accordance with the transfer information. Storage of the transfer information in the RAM area
is required before DTC operation.
When the DTC accepts a transfer request, it reads the DTC vector corresponding to the vector number. Next, the DTC
reads transfer information from the address pointed by the DTC vector, transfers data, and then writes back the transfer
information after the data transfer. Allocating transfer information in the RAM area allows data transfer of arbitrary
number of channels.
There are three transfer modes: normal transfer mode, repeat transfer mode, and block transfer mode.
Set a transfer source address in the SAR register and a transfer destination address in the DAR register. The SAR and
DAR registers are updated after the transfer according to the respective settings (increment, decrement, or fixed).
Table 19.2 lists transfer modes of the DTC.
Note 1. Set transfer source or transfer destination in the repeat area.
Note 2. Set transfer source or transfer destination in the block area.
Note 3. After data transfer of the specified count, the initial state is restored and the operation is continued (repeated).
Setting the MRB.CHNE bit to 1 allows multiple transfers (chain transfer) on a single transfer request. The setting in
combination with the MRB.CHNS bit enables a chain transfer when the specified number of data transfers is completed.
Figure 19.4 shows the operation flowchart of the DTC. Table 19.3 lists chain transfer conditions.
Table 19.2 Transfer Modes of the DTC
Transfer Mode
Data Size Transferred on Single Transfer
Request
Increment/Decrement of
Memory Address
Settable Transfer
Count
Normal transfer mode 1 byte/1 word/1 longword Incremented/decremented by
1, 2, or 4 or address fixed
1 to 65536
Repeat transfer mode*
1
1 byte/1 word/1 longword Incremented/decremented by
1, 2, or 4 or address fixed
1 to 256*
3
Block transfer mode*
2
Block size specified in CRAH
(1 to 256 bytes/1 to 256 words/1 to 256
longwords)
Incremented/decremented by
1, 2, or 4 or address fixed
1 to 65536