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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
526 of 571
NXP Semiconductors
UM10316
Chapter 30: LPC29xx General Purpose DMA (GPDMA) controller
enabled. When the DMA channel is enabled the register is updated as the destination
address is incremented and 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 that software has processed the value
read, the address may have progressed. It is intended to be read only when a channel has
stopped, in which case it shows the destination address of the last item read.
shows the bit assignments of the DMACCxDestAddr Register.
5.18 DMA Channel Linked List Item registers (DMACCxLLI - 0xE014 01x8)
The eight read/write DMACCxLLI Registers (DMACC0LLI to DMACC7LLI) contain a
word-aligned address of the next Linked List Item (LLI). If the LLI is 0, then the current LLI
is the last in the chain, and the DMA channel is disabled when all DMA transfers
associated with it are completed. Programming this register when the DMA channel is
enabled may have unpredictable side effects.
shows the bit assignments of
the DMACCxLLI Register.
5.19 DMA channel control registers (DMACCxControl - 0xE014 01xC)
The eight read/write DMACCxControl Registers (DMACC0Control to DMACC7Control)
contain DMA channel control information such as the transfer size, burst size, and transfer
width. Each register is programmed directly by software before the DMA channel is
enabled. When the channel is enabled the register is updated by following the linked list
when a complete packet of data has been transferred. Reading the register while the
channel is active does not give useful information. This is because by the time software
has processed the value read, the channel may have advanced. It is intended to be read
only when a channel has stopped.
shows the bit assignments of the
DMACCxControl Register.
5.19.1 Protection and access information
AHB access information is provided to the source and destination peripherals when a
transfer occurs. The transfer information is provided by programming the DMA channel
(the Prot bits of the DMACCxControl Register, and the Lock bit of the DMACCxConfig
Register). These bits are programmed by software.Peripherals can use this information if
necessary. Three bits of information are provided, and are used as shown in
Table 461. DMA Channel Destination Address registers (DMACCxDestAddr - 0xE014 01x4)
Bit
Name
Function
31:0
DestAddr
DMA Destination address. Reading this register will return the current destination
address.
Table 462. DMA Channel Linked List Item registers (DMACCxLLI - 0xE014 01x8)
Bit
Name
Function
31:2
LLI
Linked list item. Bits [31:2] of the address for the next LLI. Address bits [1:0] are 0.
1
R
Reserved, and must be written as 0, masked on read.
0
LM
AHB master select for loading the next LLI:
0 - AHB Master 0.
1 - AHB Master 1.