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UM10850
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 2.4 — 13 September 2016
150 of 464
NXP Semiconductors
UM10850
Chapter 12: LPC5410x DMA controller
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If channel x is configured to auto reload the descriptor on exhausting of the
descriptor (bit RELOAD in the transfer configuration of the descriptor is set), then
enable ‘clear trigger on descriptor exhausted’ by setting bit CLRTRIG in the
channel’s transfer configuration in the descriptor.
•
For channel y:
–
Configure the input trigger input mux register (DMA_ITRIG_PINMUX[0:17]) for
channel y to use any of the available DMA trigger muxes (DMA trigger mux 0/1).
–
Configure the chosen DMA trigger mux to select DMA channel x.
–
Enable hardware triggering by setting bit HWTRIGEN in the channel configuration
register.
–
Set the trigger type to edge sensitive by clearing bit TRIGTYPE in the channel
configuration register.
–
Configure the trigger edge to falling edge by clearing bit TRIGPOL in the channel
configuration register.
After completion of channel x, the descriptor may be reloaded (if configured so), but
remains untriggered. To configure the chain to auto-trigger itself, setup channels x
and y for channel chaining as described above. In addition:
•
A ping-pong configuration for both channel x and y is recommended, so that data
currently moved by channel y is not altered by channel x.
•
For channel x:
–
Configure the input trigger input multiplexer register (DMA_ITRIG_PINMUX[0:17])
for channel y to use the same DMA trigger mux that is chosen for channel y.
–
Enable hardware triggering by setting bit HWTRIGEN in the channel configuration
register.
–
Set the trigger type to edge sensitive by clearing bit TRIGTYPE in the channel
configuration register.
–
Configure the trigger edge to falling edge by clearing bit TRIGPOL in the channel
configuration register.