RX610 Group
13. Data Transfer Controller (DTC)
R01UH0032EJ0120 Rev.1.20
Page 365 of 1006
Feb 20, 2013
13.6.3
Chain Transfer when Counter = 0
The second data transfer is performed only when the counter = 0. Repeat transfer of a transfer count of 256 or more is
enabled by the re-setting for the first data transfer.
The following shows an example of configuring a 128-kbyte input buffer, where the input buffer is set so that its lower
address starts with 0000h. Figure 13.15 shows a chain transfer when the counter = 0.
1. Set normal transfer mode for input data for the first data transfer. Set the following:
Transfer source address: Fixed, CRA = 0000h (65,536 times), CHNE bit = 1 (chain transfer enabled) in MRB, CHNS
bit = 1 (chain transfer is performed only when the transfer counter is 0) in MRB, and DISEL bit = 0 (an interrupt
request to the CPU is generated when specified data transfer is completed) in MRB.
2. Prepare the upper 8-bit address of the start address at every 65,536 times of the transfer destination address for the
first data transfer in another area (such as ROM). For example, when setting the input buffer to 200000h to 21FFFFh,
prepare 21h and 20h.
3. For the second data transfer, set repeat transfer mode (transfer source: repeat area) for re-setting the transfer
destination address of the first data transfer. Specify the upper 8 bits of DAR in the first transfer data area for the
transfer destination. At this time, set CHNE bit = 0 (chain transfer disabled) in MRB and DISEL bit = 0 (an interrupt
request to the CPU is generated when specified data transfer is completed) in MRB. When setting the input buffer
mentioned above to 200000h to 21FFFFh, set the transfer counter to 2.
4. The first data transfer is performed by an interrupt 65,536 times. When the transfer counter of the first data transfer
becomes 0, the second data transfer starts. Set the upper 8 bits of the transfer source address of the first data transfer
to 21h. The transfer counter (lower 16 bits) of the transfer destination address of the first data transfer is 0000h.
5. In succession, the first data transfer is performed by an interrupt 65,536 times specified for the first data transfer.
When the transfer counter of the first data transfer becomes 0, the second data transfer starts. Set the upper 8 bits of
the transfer source address of the first data transfer to 20h. The transfer counter (lower 16 bits) of the transfer
destination address of the first data transfer is 0000h.
6. Steps 4 and 5 above are repeated infinitely. Since the second data transfer is in repeat transfer mode, no interrupt
request to the CPU is generated