UM11029
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© NXP Semiconductors N.V. 2017. All rights reserved.
User manual
Rev. 1.0 — 16 June 2017
278 of 515
NXP Semiconductors
UM11029
Chapter 16: LPC84x DMA controller
11:8
BURSTPOWER
Burst Power is used in two ways. It always selects the address wrap size
when SRCBURSTWRAP and/or DSTBURSTWRAP modes are selected
(see descriptions elsewhere in this register).
When the TRIGBURST field elsewhere in this register = 1, Burst Power
selects how many transfers are performed for each DMA trigger. This can be
used, for example, with peripherals that contain a FIFO that can initiate a
DMA operation when the FIFO reaches a certain level.
0000: Burst size = 1 (2
0
).
0001: Burst size = 2 (2
1
).
0010: Burst size = 4 (2
2
).
...
1010: Burst size = 1024 (2
10
). This corresponds to the maximum supported
transfer count.
others: not supported.
The total transfer length as defined in the XFERCOUNT bits in the
XFERCFG register must be an even multiple of the burst size.
0
13:12 -
Reserved. Read value is undefined, only zero should be written.
NA
14
SRCBURSTWRAP
Source Burst Wrap. When enabled, the source data address for the DMA is
“wrapped”, meaning that the source address range for each burst will be the
same. As an example, this could be used to read several sequential
registers from a peripheral for each DMA burst, reading the same registers
again for each burst.
0
0
Disabled. Source burst wrapping is not enabled for this DMA channel.
1
Enabled. Source burst wrapping is enabled for this DMA channel.
15
DSTBURSTWRAP
Destination Burst Wrap. When enabled, the destination data address for the
DMA is “wrapped”, meaning that the destination address range for each
burst will be the same. As an example, this could be used to write several
sequential registers to a peripheral for each DMA burst, writing the same
registers again for each burst.
0
0
Disabled. Destination burst wrapping is not enabled for this DMA channel.
1
Enabled. Destination burst wrapping is enabled for this DMA channel.
18:16 CHPRIORITY
Priority of this channel when multiple DMA requests are pending.
Eight priority levels are supported.
0x0 = highest priority.
0x7 = lowest priority.
0
31:19 -
Reserved. Read value is undefined, only zero should be written.
NA
Table 317. Configuration registers for channel 0 to 24 (CFG[0:24], addresses 0x5000 8400 (CFG0) to address 0x5000
8564 (CFG24)) bit description
Bit
Symbol
Value Description
Reset
value