CHAPTER 6 DMA FUNCTIONS (DMA CONTROLLER)
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User’s Manual U15195EJ5V0UD
Figure 6-3 shows a single transfer mode example in which a lower priority DMA transfer request is generated
within one clock after the end of a single transfer. DMA channels 0 and 3 are used for a single transfer. When two
DMA transfer request signals are activated at the same time, the two DMA transfers are performed alternately.
Figure 6-3. Single Transfer Example 3
CPU
CPU
DMA3
DMA0
CPU
DMA0
CPU
CPU
CPU
CPU
DMA0
CPU
DMA0
DMA3
CPU
CPU
DMA0
DMARQ3
CPU
DMA0
DMA channel 0
terminal count
Note
Note
Note
Note
DMARQ0
DMA channel 3
terminal count
Note
Note
Note
(Internal signal)
(Internal signal)
Note
The bus is always released.
Figure 6-4 shows a single transfer mode example in which two or more lower priority DMA transfer requests are
generated within one clock after the end of a single transfer. DMA channels 0, 2, and 3 are used for a single transfer.
When three or more DMA transfer request signals are activated at the same time, the two highest priority DMA
transfers are performed alternately.
Figure 6-4. Single Transfer Example 4
DMA2
CPU
DMA3
CPU
CPU
DMA3
CPU
CPU
DMA2
DMA0
CPU
DMARQ3
DMA0
Note
Note
Note
DMARQ2
Note
Note
DMARQ0
DMA2
CPU
DMA channel 0
terminal count
Note
DMA3
CPU
DMA2
CPU
CPU
DMA3
DMA channel 3
terminal count
Note
CPU
CPU
Note
DMA channel 2
terminal count
Note
(Internal signal)
(Internal signal)
(Internal signal)
Note
The bus is always released.