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UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
394 of 1269
NXP Semiconductors
UM10503
Chapter 19: LPC43xx General Purpose DMA (GPDMA) controller
19.6.15 DMA Channel registers
The channel registers are used to program the eight DMA channels. These registers
consist of:
•
Eight SRCADDR Registers.
•
Eight DESTADDR Registers.
•
Eight LLI Registers.
•
Eight CONTROL Registers.
•
Eight CONFIG Registers.
When performing scatter/gather DMA, the first four of these are automatically updated.
19.6.16 DMA Channel Source Address Registers
The eight read/write SRCADDR Registers contain the current source address
(byte-aligned) of the data to be transferred. Each register is programmed directly by
software before the appropriate channel is enabled. When the DMA channel is enabled
this register is updated:
•
As the source address is incremented.
•
By following the linked list when a complete packet of data has been transferred.
Reading the register when the channel is active does not provide useful information. This
is because by the time software has processed the value read, the address may have
progressed. It is intended to be read only when the channel has stopped, in which case it
shows the source address of the last item read.
Note: The source and destination addresses must be aligned to the source and
destination widths.
Table 285. DMA Synchronization Register (SYNC, address 0x4000 2034) bit description
Bit
Symbol
Description
Reset
value
Access
15:0
DMACSYNC
Controls the synchronization logic for DMA request
signals. Each bit represents one set of DMA request
lines as described in the preceding text:
0 - synchronization logic for the corresponding DMA
request signals are disabled.
1 - synchronization logic for the corresponding
request line signals are enabled.
0x00
R/W
31:16
-
Reserved. Read undefined. Write reserved bits as
zero.
-
-
Table 286. DMA Channel Source Address Registers (SRCADDR[0:7], 0x4000 2100
(SRCADDR0) to 0x4000 21E0 (SRCADDR7)) bit description
Bit
Symbol
Description
Reset value
Access
31:0
SRCADDR
DMA source address. Reading this register will
return the current source address.
0x0000 0000 R/W