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DMAC
9
9-38
32185/32186 Group Hardware Manual
Rev.1.10 REJ09B0235-0110 May 15, 07
9.3 Functional Description of DMAC
9.3.1 DMA Transfer Request Sources
For each DMA channel (channels 0–9), DMA transfer can be requested from two or more sources. There
are various causes or sources of DMA transfer request, so that DMA transfer can be started by a request
from some internal peripheral I/O, in software by a program, or upon completion of one transfer or all
transfers on another DMA channel (cascade mode).
The causes or sources of DMA transfer requests are selected using the transfer request source select bits
REQSLn on each channel (DMAn Channel Control Register 0 bits 2–3) or the extended transfer request
source select bits REQESELn (DMAn Channel Control Register 1 bits 12–15). The tables below list the
causes or sources of DMA transfer requests on each channel.
Table 9.3.1 DMA Transfer Request Sources and Generation Timings on DMA0
REQSL0
DMA Transfer Request Source
DMA Transfer Request Generation Timing
0
Software start or one DMA2
When any data is written to the DMA0 Software Request Generation
transfer completed
Register (software start) or when one DMA2 transfer is completed
(cascade mode)
0
1
A/D0 conversion completed
When A/D0 conversion is completed
1
0
MJT (TIO8_udf)
When MJT TIO8 underflows
1
Extended DMA0 transfer request
The source selected by the DMA0 Channel Control Register 1
source selected
(DM0CNT1) REQESEL0 bits (see below)
REQESEL0 DMA Transfer Request Source
DMA Transfer Request Generation Timing
0000
MJT (input event bus 2)
When MJT input event bus 2 signal is generated
0001
MJT (TID0_udf/ovf)
When MJT TID0 underflow/overflow occurs
0010
CAN (CAN0_S0/S31)
When CAN0 slot 0 transmission failed or slot 31 transmission/reception
finished
0011
Common 1) MJT (input event bus 1)
When MJT input event bus 1 signal is generated
0100
Common 2) MJT (input event bus 3)
When MJT input event bus 3 signal is generated
0101
Common 3) MJT (output event bus 2)
When MJT output event bus 2 signal is generated
0110
Common 4) MJT (output event bus 3)
When MJT output event bus 3 signal is generated
0111
Common 5) A/D0 conversion completed
When A/D0 conversion is completed
1000
Common 6) MJT (TIN0S)
When MJT TIN0 input signal is generated
1001
Common 7) MJT (TIO8_udf)
When MJT TIO8 underflow occurs
1010
Common 8) MJT (TIN30S)
When MJT TIN30 input signal is generated
1011
Common 9) MJT (TIO9_udf)
When MJT TIO9 underflow occurs
1100
Common 10) Settings inhibited
–
1101
MJT (TOU1_0irq)
When MJT TOU1_0 interrupt request is generated
1110
DRI (DIN0)
When DRI DIN0 event detection interrupt is generated
1111
SIO4_TXD (transmit buffer empty)
When SIO4 transmit buffer empty interrupt is generated
9.3 Functional Description of DMAC