UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
401 of 1269
NXP Semiconductors
UM10503
Chapter 19: LPC43xx General Purpose DMA (GPDMA) controller
19.6.20.1 Lock control
The lock control may set the lock bit by writing a 1 to bit 16 of the CONFIG Register. When
a burst occurs, the AHB arbiter will not de-grant the master during the burst until the lock
is deasserted. The DMA Controller can be locked for a a single burst such as a long
source fetch burst or a long destination drain burst. The DMA Controller does not usually
assert the lock continuously for a source fetch burst followed by a destination drain burst.
There are situations when the DMA Controller asserts the lock for source transfers
followed by destination transfers. This is possible when internal conditions in the DMA
Controller permit it to perform a source fetch followed by a destination drain back-to-back.
19.6.20.2 Flow control and transfer type
lists the bit values of the three flow control and transfer type bits identified in
Table
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.
RO
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.
R/W
0
Enable DMA requests.
1
Ignore further source DMA requests.
31:19 -
Reserved, do not modify, masked on read.
-
Table 290. DMA Channel Configuration registers (CONFIG[0:7], 0x4000 2110 (CONFIG0) to 0x4000 21F0 (CONFIG7))
bit description
…continued
Bit
Symbol
Value
Description
Reset
value
Access
Table 291. Flow control and transfer type bits
Bit value
Transfer type
Controller
000
Memory to memory
DMA
001
Memory to peripheral
DMA
010
Peripheral to memory
DMA
011
Source peripheral to destination peripheral
DMA
100
Source peripheral to destination peripheral
Destination peripheral
101
Memory to peripheral
Peripheral
110
Peripheral to memory
Peripheral
111
Source peripheral to destination peripheral
Source peripheral