r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 444

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 8 EXDMA Controller (EXDMAC)
8.4.5
There are two transfer modes: normal transfer mode and block transfer mode. When the activation
source is an external request, either normal transfer mode or block transfer mode can be selected.
When the activation source is an auto request, normal transfer mode is used.
(1)
In normal transfer mode, transfer of one transfer unit is processed in response to one transfer
request. EDTCR functions as a 24-bit transfer counter.
The ETEND signal is output only for the last DMA transfer. The EDRAK signal is output each
time a transfer request is accepted and transfer processing is started.
Figure 8.7 shows examples of DMA transfer timing in normal transfer mode.
Rev. 1.00 Sep. 19, 2008 Page 416 of 1270
REJ09B0466-0100
Transfer conditions:
Transfer conditions:
Bus cycle
ETEND
EDREQ
EDRAK
Bus cycle
EDACK
Dual address mode, auto request mode
Single address mode, external request mode
Normal Transfer Mode
Transfer Modes
Figure 8.7 Examples of Timing in Normal Transfer Mode
Read
transfer cycle
EXDMA
Write
EXDMA
Read
Last EXDMA
transfer cycle
EXDMA
Write