CHAPTER 6 DMA FUNCTIONS (DMA CONTROLLER)
225
User’s Manual U14359EJ4V0UM
Figure 6-4 is an example of single transfer where a DMA transfer request with the lower priority is issued one clock
after single transfer has been completed. DMA channels 0 and 3 are used for single transfer. If two DMA transfer
request signals are asserted active at the same time, two DMA transfer operations are alternately executed.
Figure 6-4. Single Transfer Example 3
CPU CPU
CPU
DMA0
DMA0
CPU DMA0
CPU DMA0 CPU DMA0 CPU
CPU CPU
DMA0
CPU DMA3
CPU DMA3
DMA channel 3
terminal count
DMA channel 0
terminal count
DMARQ3
(input)
DMARQ0
(input)
Note
Note
Note
Note
Note
Note
Note
Note
The bus is always released.
Figure 6-5 is an example of single transfer where two or more DMA transfer requests with the lower priority are
issued one clock after single transfer has been completed. DMA channels 0, 2, and 3 are used for single transfer. If
three or more DMA transfer request signals are asserted active at the same time, two DMA transfer operations are
alternately executed, always starting from the one with the highest priority.
Figure 6-5. Single Transfer Example 4
CPU DMA3 CPU DMA3 CPU DMA2
CPU DMA2
CPU DMA2
CPU DMA2
CPU DMA3
CPU
CPU CPU
DMA3
CPU DMA0
CPU DMA0
DMA channel 0
terminal count
DMA channel 2
terminal count
DMA channel 3
terminal count
DMARQ2
(input)
DMARQ3
(input)
DMARQ0
(input)
Note
Note
Note
Note
Note
Note
Note
Note
Note
Note
The bus is always released.