R01UH0822EJ0100 Rev.1.00
Page 266 of 1041
Jul 31, 2019
RX13T Group
16. Data Transfer Controller (DTCb)
16.4.2
Transfer Information Write-Back Skip Function
16.4.2.1
Write-Back Skip by Fixing Addresses
When the MRA.SM[1:0] bits or the MRB.DM[1:0] bits are set to “address is fixed” (00b or 01b), a part of transfer
information is not written back. This function is performed independently of the setting of short-address mode or full-
address mode.
lists transfer information write-back skip conditions and applicable registers. The CRA and CRB registers
are written back independently of the setting of short-address mode or full-address mode.
Furthermore, in full-address mode, write-back of registers MRA, MRB, and MRC is skipped.
16.4.2.2
Write-Back Skip by the MRA.WBDIS Bit
When the MRA.WBDIS bit is 1, the transfer information (SAR, DAR, CRA, and CRB) is not written back regardless of
the settings of the transfer information.
The transfer information on the memory is not updated, data can be transferred by the DTC without copying the transfer
information from ROM to RAM. Skipping a write-back reduces time for post-processing of the data transfer.
Table 16.5
Transfer Information Write-Back Skip Conditions and Applicable Registers
SAR Register
DAR Register
b3
b2
b3
b2
0
0
0
0
Skip
Skip
0
0
0
1
0
1
0
0
0
1
0
1
0
0
1
0
Skip
Write-back
0
0
1
1
0
1
1
0
0
1
1
1
1
0
0
0
Write-back
Skip
1
0
0
1
1
1
0
0
1
1
0
1
1
0
1
0
Write-back
Write-back
1
0
1
1
1
1
1
0
1
1
1
1