13 DMA CONTROLLER (DMAC)
13-16
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
DMAC Pause Status Register (DMAC_PAUSE_STAT)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
DMAC Pause
Status Register
(DMAC_
PAUSE_STAT)
0x30211c
(32 bits)
D31–8 –
reserved
–
–
–
0 when being read.
D7
PAUSE7
Ch.7 pause status
1 Paused
0 Not paused
0
R
D6
PAUSE6
Ch.6 pause status
1 Paused
0 Not paused
0
R
D5
PAUSE5
Ch.5 pause status
1 Paused
0 Not paused
0
R
D4
PAUSE4
Ch.4 pause status
1 Paused
0 Not paused
0
R
D3
PAUSE3
Ch.3 pause status
1 Paused
0 Not paused
0
R
D2
PAUSE2
Ch.2 pause status
1 Paused
0 Not paused
0
R
D1
PAUSE1
Ch.1 pause status
1 Paused
0 Not paused
0
R
D0
PAUSE0
Ch.0 pause status
1 Paused
0 Not paused
0
R
D[31:8] Reserved
D[7:0]
PAUSE
x
: Ch.
x
Paused Status Bit
Indicates whether the successive transfer operation is suspended due to a high-priority DMA transfer or
not.
1 (R):
Suspended
0 (R):
Status other than suspension (default)
When a DMA request is generated that has higher priority than that of the channel in operation, the
channel performing a transfer saves control information required for resuming transfers (such as the
current transfer count and the transfer source and destination addresses) as soon as the current data
transfer is completed and then suspends transfers. In this case, PAUSE
x
is also set to 1, indicating that
the channel has suspended a transfer. After that, the high-priority DMA transfer is executed. After the
transfer is completed, suspended DMA transfers are resumed. At this time, the DMAC checks PAUSE
x
and TRG
x
/DMAC_TRG_FLG register, and processes the channels with their bits set, starting with one
with the highest-priority (with the channel with the lowest number).
When the DMAC resumes DMA transfers that have been suspended, PAUSE
x
is cleared.