
UM10800
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User manual
Rev. 1.2 — 5 October 2016
176 of 487
NXP Semiconductors
UM10800
Chapter 12: LPC82x DMA controller
12.6.11 Interrupt A register
The IntA0 register contains the interrupt A status for each DMA channel. The status will be
set when the SETINTA bit is 1 in the transfer configuration for a channel, when the
descriptor becomes exhausted. Writing a 1 to a bit in these registers clears the related
INTA flag. Writing 0 has no effect. Any interrupt pending status in this register will be
reflected on the DMA interrupt output if it is enabled in the related INTENSET register.
Remark:
The error status is not included in this register. The error status is reported in the
ERRINT0 status register.
12.6.12 Interrupt B register
The INTB0 register contains the interrupt B status for each DMA channel. The status will
be set when the SETINTB bit is 1 in the transfer configuration for a channel, when the
descriptor becomes exhausted. Writing a 1 to a bit in the register clears the related INTB
flag. Writing 0 has no effect. Any interrupt pending status in this register will be reflected
on the DMA interrupt output if it is enabled in the INTENSET register.
Remark:
The error status is not included in this register. The error status is reported in the
ERRINT0 status register.
12.6.13 Set Valid register
The SETVALID0 register allows setting the Valid bit in the CTRLSTAT register for one or
more DMA channels. See
for a description of the VALID bit.
The CFGVALID and SV (set valid) bits allow more direct DMA block timing control by
software. Each Channel Descriptor, in a sequence of descriptors, can be validated by
either the setting of the CFGVALID bit or by setting the channel's SETVALID flag.
Normally, the CFGVALID bit is set. This tells the DMA that the Channel Descriptor is
active and can be executed. The DMA will continue sequencing through descriptor blocks
whose CFGVALID bit are set without further software intervention. Leaving a CFGVALID
bit set to 0 allows the DMA sequence to pause at the Descriptor until software triggers the
continuation. If, during DMA transmission, a Channel Descriptor is found with CFGVALID
Table 165. Interrupt A register 0 (INTA0, address 0x5000 8058) bit description
Bit
Symbol
Description
Reset value
17:0
IA
Interrupt A status for DMA channel n. Bit n corresponds to DMA
channel n.
0 = the DMA channel interrupt A is not active.
1 = the DMA channel interrupt A is active.
0
31:18 -
Reserved.
-
Table 166. Interrupt B register 0 (INTB0, address 0x5000 8060) bit description
Bit
Symbol
Description
Reset value
17:0
IB
Interrupt B status for DMA channel n. Bit n corresponds to DMA
channel n.
0 = the DMA channel interrupt B is not active.
1 = the DMA channel interrupt B is active.
0
31:18 -
Reserved.
-