r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 460

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 8 EXDMA Controller (EXDMAC)
(3)
Figure 8.17 shows an example of transfer when ETEND output is enabled, and word-size, block
transfer mode (cycle steal mode) is performed from external 16-bit, 2-state access space to
external 16-bit, 2-state access space.
One block is transferred in response to one transfer request, and after the transfer, the bus is
released. While the bus is released, one or more CPU, DMAC, or DTC bus cycles are initiated.
Rev. 1.00 Sep. 19, 2008 Page 430 of 1342
REJ09B0467-0100
φ
Address bus
RD
HWR
LWR
ETEND
Block Transfer Mode (Cycle Steal Mode)
Figure 8.17 Example of Block Transfer Mode (Cycle Steal Mode) Transfer
Bus
release
DMA
read
DMA
write
Block transfer
DMA
read
DMA
write
release
Bus
DMA
read
Last block transfer
DMA
write
DMA
read
DMA
write
Bus
release