Fujitsu FR60 Hardware Manual page 542

CHAPTER 16 DMA CONTROLLER (DMAC)
■ Operation Flowchart for Demand Transfer
DENB=>0
Reload enable
Demand transfer
- Only requests (level detection) from the external pin (DREQ) are accepted.
Activation by other sources is disabled.
- Access to an external area is required (since access to an external area
becomes the next activation source).
- The number of blocks is always "1", regardless of the settings.
- Interrupt clear and the DMA interrupt are issued when transfer for the
number of times specified is completed.
524
Figure 16.4-3 Demand Transfer
DMA stop
DENB=1
None
Activation request
wait
Activation request
Load the initial address,
transfer count, and
number of blocks
Calculate the address for
transfer source address access
Calculate the address for transfer
destination address access
Transfer count - 1
Write back the address,
transfer count, and number
of blocks
DTC=0
Interrupt clear
DMA transfer end
One-time access for fly-by
Only when the peripheral interrupt
activation source is selected
Interrupt cleared
DMA interrupted