56
XMEGA B [DATASHEET]
8291B–AVR–01/2013
Bit 1:0 – BURSTLEN[1:0]: Burst Mode
These bits decide the DMA channel burst mode according to
. These bits cannot be changed if the
channel is busy.
Table 5-2.
DMA channel burst mode
Table 5-3.
Summary of triggers, transaction complete flag and channel disable according to DMA channel
configuration.
5.14.2 CTRLB – Control register B
Bit 7 – CHBUSY: Channel Busy
When the DMA channel starts a DMA transaction, the CHBUSY flag will be read as one. This flag is automatically
cleared when the DMA channel is disabled, when the channel transaction complete interrupt flag is set or when the
channel error interrupt flag is set.
BURSTLEN[1:0]
Group Configuration
Description
00
1BYTE
1 byte burst mode
01
2BYTE
2 bytes burst mode
10
4BYTE
4 bytes burst mode
11
8BYTE
8 bytes burst mode
REPEAT
SINGLE
REPCNT
Trigger
Flag Set After
Channel Disabled After
0
0
0
Block
1 block
1 block
0
0
1
Block
1 block
1 block
0
0
n > 1
Block
1 block
1 block
0
1
0
BURSTLEN
1 block
1 block
0
1
1
BURSTLEN
1 block
1 block
0
1
n > 1
BURSTLEN
1 block
1 block
1
0
0
Block
Each block
Each block
1
0
1
Transaction
1 block
1 block
1
0
n > 1
Transaction
n blocks
n blocks
1
1
0
BURSTLEN
Each block
Never
1
1
1
BURSTLEN
1 block
1 block
1
1
n > 1
BURSTLEN
n blocks
n blocks
Bit
7
6
5
4
3
2
1
0
CHBUSY
CHPEND
ERRIF
TRNIF
ERRINTLVL[1:0]
TRNINTLVL[1:0]
Read/Write
R
R
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Содержание XMEGA B
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