
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
174 of 487
NXP Semiconductors
UM10800
Chapter 12: LPC82x DMA controller
12.6.5 Enable Clear register
The ENABLECLR0 register is used to clear the channel enable bits in ENABLESET0.
This register is write-only.
12.6.6 Active status register
The ACTIVE0 register indicates which DMA channels are active at the point when the
read occurs. The register is read-only.
A DMA channel is considered active when a DMA operation has been started but not yet
fully completed. The Active status will persist from a DMA operation being started, until
the pipeline is empty after end of the last descriptor (when there is no reload). An active
channel may be aborted by software by setting the appropriate bit in one of the Abort
register (see
).
12.6.7 Busy status register
The BUSY0 register indicates which DMA channels is busy at the point when the read
occurs. This registers is read-only.
A DMA channel is considered busy when there is any operation related to that channel in
the DMA controller’s internal pipeline. This information can be used after a DMA channel
is disabled by software (but still active), allowing confirmation that there are no remaining
operations in progress for that channel.
Table 159. Enable Clear register 0 (ENABLECLR0, address 0x5000 8028) bit description
Bit
Symbol
Description
Reset value
17:0
CLR
Writing ones to this register clears the corresponding bits in
ENABLESET0. Bit n clears the channel enable bit n.
NA
31:18 -
Reserved.
-
Table 160. Active status register 0 (ACTIVE0, address 0x5000 8030) bit description
Bit
Symbol
Description
Reset
value
17:0
ACT
Active flag for DMA channel n. Bit n corresponds to DMA channel
n.
0 = not active.
1 = active.
0
31:18 -
Reserved.
-
Table 161. Busy status register 0 (BUSY0, address 0x5000 8038) bit description
Bit
Symbol
Description
Reset
value
17:0
BSY
Busy flag for DMA channel n. Bit n corresponds to DMA channel n.
0 = not busy.
1 = busy.
0
31:18 -
Reserved.
-