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9
9-2
Rev.1.0
9.1 Outline of DMAC
The microcomputer has 10-channel DMA (Direct Memory Access) Controller allowing data to be
transferred at high speed between internal peripheral I/Os, between internal RAM and internal
peripheral I/O, and between internal RAMs when triggered in software or by request from internal
peripheral I/O.
Table 9.1.1 Outline of DMAC
Item
Content
Number of channels
10 channels
Transfer request
Software trigger
Request from internal peripheral I/O: A-D converter, input/output timer,
serial I/O (reception complete, transmit buffer empty), or PD controller
Cascaded operation between DMA channels (Note)
Maximum transfer count
256 times
Transferable address space
64 Kbytes (address space in H'0080 0000 through H'0080 FFFF)
Supports transfers between internal peripheral I/Os, between internal
RAM and internal peripheral I/O, and between internal RAMs
Transfer data size
16 or 8 bits
Transfer method
Single-transfer method DMA (control of internal bus released for each
transfer performed), dual-address transfer
Transfer mode
Single transfer mode
Direction of transfer
Selectable among three modes for the source and destination
Address fixed
Address increment
Ring buffer
Channel priority
Channel 0 > channel 1 > channel 2 > channel 3 > channel 4 > channel 5 >
channel 6 > channel 7 > channel 8 > channel 9 >
(fixed priority)
Maximum transfer rate
13.3 Mbytes per second (when internal peripheral clock = 20 MHz)
Interrupt request
Group interrupt request can be generated when any transfer count register underflows
Transfer area
64 Kbytes in H'0080 0000 through H'0080 FFFF
(transferable in the entire internal RAM and SFR area)
DMAC
9.1 Outline of DMAC
Note: The DMA channels can be cascaded in the manner shown below.
Completion of one DMA transfer on channel 0 starts a DMA transfer on channel 1.
Completion of one DMA transfer on channel 1 starts a DMA transfer on channel 2.
Completion of one DMA transfer on channel 2 starts a DMA transfer on channel 0.
Completion of one DMA transfer on channel 3 starts a DMA transfer on channel 4.
Completion of one DMA transfer on channel 5 starts a DMA transfer on channel 6.
Completion of one DMA transfer on channel 6 starts a DMA transfer on channel 7.
Completion of one DMA transfer on channel 7 starts a DMA transfer on channel 5.
Completion of one DMA transfer on channel 8 starts a DMA transfer on channel 9.
Completion of one DMA transfer on channel 9 starts a DMA transfer on channel 1-9.
Completion of all DMA transfers on channel 0 (i.e., the transfer count register underflows) starts a DMA transfer on channel 5.
Completion of all DMA transfers on channel 1 (i.e., the transfer count register underflows) starts DMA transfers on channels 0-9.
Completion of all DMA transfers on channel 3 (i.e., the transfer count register underflows) starts DMA transfers on channel 8.