DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
529 of 571
NXP Semiconductors
UM10316
Chapter 30: LPC29xx General Purpose DMA (GPDMA) controller
Table 464. Channel Configuration registers (DMACCxConfig - 0xE014 01x0)
Bit
Name
Function
31:19
Reserved
Reserved, do not modify, masked on read.
18
H
Halt:
0 = enable DMA requests.
1 = ignore further source DMA requests.
The contents of the channel FIFO are drained.
This value can be used with the Active and Channel Enable bits to cleanly disable a
DMA channel.
17
A
Active:
0 = there is no data in the FIFO of the channel.
1 = the channel FIFO has data.
This value can be used with the Halt and Channel Enable bits to cleanly disable a
DMA channel. This is a read-only bit.
16
L
Lock. When set, this bit enables locked transfers.
15
ITC
Terminal count interrupt mask. When cleared, this bit masks out the terminal count
interrupt of the relevant channel.
14
IE
Interrupt error mask. When cleared, this bit masks out the error interrupt of the
relevant channel.
13:11
FlowCntrl
Flow control and transfer type. This value indicates the flow controller and transfer
type. The flow controller can be the DMA Controller, the source peripheral, or the
destination peripheral.
The transfer type can be memory-to-memory, memory-to-peripheral,
peripheral-to-memory, or peripheral-to-peripheral.
Refer to
for the encoding of this field.
10:6
DestPeripheral
Destination peripheral. This value selects the DMA destination request peripheral.
This field is ignored if the destination of the transfer is to memory. See
for peripheral identification.
5:1
SrcPeripheral
Source peripheral. This value selects the DMA source request peripheral. This field is
ignored if the source of the transfer is from memory. See
for peripheral
identification.
0
E
Channel enable. Reading this bit indicates whether a channel is currently enabled or
disabled:
0 = channel disabled.
1 = channel enabled.
The Channel Enable bit status can also be found by reading the DMACEnbldChns
Register.
A channel is enabled by setting this bit.
A channel can be disabled by clearing the Enable bit. This causes the current AHB
transfer (if one is in progress) to complete and the channel is then disabled. Any data
in the FIFO of the relevant channel is lost. Restarting the channel by setting the
Channel Enable bit has unpredictable effects, the channel must be fully re-initialized.
The channel is also disabled, and Channel Enable bit cleared, when the last LLI is
reached, the DMA transfer is completed, or if a channel error is encountered.
If a channel must be disabled without losing data in the FIFO, the Halt bit must be set
so that further DMA requests are ignored. The Active bit must then be polled until it
reaches 0, indicating that there is no data left in the FIFO. Finally, the Channel Enable
bit can be cleared.