r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 466

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

Section 8 EXDMA Controller (EXDMAC)
After one byte or word has been transferred in response to one transfer request, the bus is released.
While the bus is released, one or more CPU, DMAC, or DTC bus cycles are initiated.
(2)
Figure 8.24 shows an example of transfer when ETEND output is enabled, and byte-size, single
address mode transfer (write) is performed from an external device to external 8-bit, 2-state access
space.
Rev. 1.00 Sep. 19, 2008 Page 436 of 1342
REJ09B0467-0100
φ
Address bus
RD
EDACK
ETEND
Single Address Mode (Write)
φ
Address bus
HWR
LWR
EDACK
ETEND
Bus release
Figure 8.23 Example of Single Address Mode (Word Read) Transfer
Figure 8.24 Example of Single Address Mode (Byte Write) Transfer
Bus release
DMA read
DMA write
Bus release
Bus release
DMA write
Bus release
DMA read
DMA write
Bus release
Bus release
DMA write
Last transfer cycle
transfer
cycle
Last
DMA read
Bus release
Bus
releas e