HD6412332 RENESAS [Renesas Technology Corp], HD6412332 Datasheet - Page 314

• Manufacturer Part Number: HD6412332
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

7.5.14
There can be no break between a DMA cycle read and a DMA cycle write. This means that a
refresh cycle, external bus release cycle, or DTC cycle is not generated between the external read
and external write in a DMA cycle.
In the case of successive read and write cycles, such as in burst transfer or block transfer, a refresh
or external bus released state may be inserted after a write cycle. Since the DTC has a lower
priority than the DMAC, the DTC does not operate until the DMAC releases the bus.
When DMA cycle reads or writes are accesses to on-chip memory or internal I/O registers, these
DMA cycles can be executed at the same time as refresh cycles or external bus release. However,
simultaneous operation may not be possible when a write buffer is used.
Rev.4.00 Sep. 07, 2007 Page 284 of 1210
REJ09B0245-0400
Relation Between the DMAC and External Bus Requests, Refresh Cycles, and the
DTC