HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 329

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

If transfer requests are issued simultaneously for more than one channel, or if a transfer request for
another channel is issued during a transfer, when the bus is released the DMAC selects the
highest-priority channel from among those issuing a request according to the priority order shown
in table 7.13.
During burst transfer, or when one block is being transferred in block transfer, the channel will not
be changed until the end of the transfer.
Figure 7.35 shows a transfer example in which transfer requests are issued simultaneously for
channels 0A, 0B, and 1.
Address bus
DMA control
Channel 0A
Channel 0B
Channel 1
HWR
LWR
RD
φ
release
Idle
Bus
Request clear
Read
DMA read
Request
hold
Request
hold
Figure 7.35 Example of Multi-Channel Transfer
Write
Channel 0A
transfer
Selection
DMA write
selection
Non-
Idle
Section 7 DMA Controller (Not Supported in the H8S/2321)
release
Request clear
Bus
Read
DMA read
Request
hold
Write
Channel 0B
transfer
Rev.6.00 Sep. 27, 2007 Page 299 of 1268
Selection
DMA write
Idle
release
Request clear
Bus
Read
DMA read
Channel 1 transfer
Write
REJ09B0220-0600
DMA write
Read
DMA
read