h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 210

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

Figure 7.6 shows an example of the timing in burst mode.
7.4.5
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.
Normal Transfer Mode: In normal transfer mode, transfer of one transfer unit is processed in
response to one transfer request. DMTCR functions as a 24-bit transfer counter.
The TEND signal is output only for the last DMA transfer. The DRAK signal is output each time a
transfer request is accepted and transfer processing is started. Figure 7.7 shows examples of DMA
transfer timing in normal transfer mode.
Rev. 2.00, 03/04, page 178 of 534
Bus cycle
Bus cycle
Bus cycle
Transfer Modes (Normal Transfer Mode/Block Transfer Mode)
Figure 7.7 Examples of Timing in Normal Transfer Mode
CPU
Figure 7.6 Examples of Timing in Burst Mode
(1) Dual address mode, auto request mode
(2) Single address mode, external request mode
Read
transfer cycle
CPU
DMA
Write
Auto request mode
DMAC
DMA
CPU cycle not generated
DMAC
Read
transfer cycle
Last DMA
Write
DMA
DMAC
CPU
CPU