RX610 Group
12. DMA Controller (DMAC)
R01UH0032EJ0120 Rev.1.20
Page 312 of 1006
Feb 20, 2013
12.2.5
DMA Control Register D (DMCRD)
b7
b6
b5
b4
b3
b2
b1
b0
Value after reset:
0
0
0
0
0
0
0
0
—
—
—
—
—
—
—
DREQ
Addresses: DMAC0.DMCRD 0008 2406h, DMAC1.DMCRD 0008 240Eh
DMAC2.DMCRD 0008 2416h, DMAC3.DMCRD 0008 241Eh
Bit
Symbol
Bit Name
Description
R/W
b0
DREQ
DMA Transfer Request
0: No DMA transfer request is generated
1: A DMA transfer request is generated
R/W
b7 to b1
Reserved
These bits are always read as 0. The write value should
always be 0.
R/W
DMCRD is used to control DMA transfer.
DREQ Bit (DMA Transfer Request)
The DREQ bit indicates whether a DMA transfer request is present or not.
The value of the DREQ bit varies according to the presence or absence of a DMA transfer request even when the DMAC
is stopped or DMA transfer is disabled.
If software triggering is specified as a source of DMA transfer requests, the program generates a DMA transfer request
by writing 1 to this bit.
If software triggering is not specified as a source of DMA transfer requests, the program should not write 1 to this bit.
Write 0 to the DREQ bit while data transfer is not in progress, i.e. while the DMAC is stopped or DMA transfer is
disabled. Writing of 1 can proceed regardless of the state of DMA transfer.
The DREQ bit is set to 1 or cleared to 0 according to the source of DMA transfer requests as described below.
(1) When the source of DMA transfer requests is a software trigger
[Setting condition]
•
The program writing 1 to the bit
[Clearing conditions]
•
The program writing 0 to the bit
•
The start of data transfer following acceptance of a DMA transfer request
(2) When the source of DMA transfer requests is other than a software trigger
[Setting condition]
•
Detection of a source of DMA transfer requests that has been selected in the corresponding
DMACm.DMCRA.DCTG[5:0] bits
[Clearing conditions]
•
The program writing 0 to the bit
•
The start of data transfer following acceptance of a DMA transfer request
Summary of Contents for RX600 Series
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