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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
528 of 571
NXP Semiconductors
UM10316
Chapter 30: LPC29xx General Purpose DMA (GPDMA) controller
5.20 Channel Configuration registers (DMACCxConfig - 0xE014 01x0)
The eight DMACCxConfig Registers (DMACC0Config to DMACC7Config) are read/write
with the exception of bit[17] which is read-only. Used these to configure the DMA channel.
The registers are not updated when a new LLI is requested.
shows the bit
assignments of the DMACCxConfig Register.
17:15
DBSize
Destination burst size. Indicates the number of transfers that make up a destination
burst transfer request. This value must be set to the burst size of the destination
peripheral or, if the destination is memory, to the memory boundary size. The burst
size is the amount of data that is transferred when the DMACBREQ signal goes
active in the destination peripheral.
000 - 1
001 - 4
010 - 8
011 - 16
100 - 32
101 - 64
110 - 128
111 - 256
14:12
SBSize
Source burst size. Indicates the number of transfers that make up a source burst.
This value must be set to the burst size of the source peripheral, or if the source is
memory, to the memory boundary size. The burst size is the amount of data that is
transferred when the DMACBREQ signal goes active in the source peripheral.
000 - 1
001 - 4
010 - 8
011 - 16
100 - 32
101 - 64
110 - 128
111 - 256
11:0
TransferSize
Transfer size. A write to this field sets the size of the transfer when the DMA
Controller is the flow controller. The transfer size value must be set before the
channel is enabled. Transfer size is updated as data transfers are completed.
A read from this field indicates the number of transfers completed on the destination
bus. Reading the register when the channel is active does not give useful information
because by the time that the software has processed the value read, the channel
might have progressed. It is intended to be used only when a channel is enabled and
then disabled.
The transfer size value is not used if the DMA Controller is not the flow controller.
Table 463. DMA channel control registers (DMACCxControl - 0xE014 01xC)
…continued
Bit
Name
Function