
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
331 of 487
NXP Semiconductors
UM10800
Chapter 21: 12-bit Analog-to-Digital Converter (ADC)
27
BURST
Writing a 1 to this bit will cause this conversion sequence to be continuously
cycled through. Other sequence A triggers will be ignored while this bit is set.
Repeated conversions can be halted by clearing this bit. The sequence
currently in progress will be completed before conversions are terminated.
0
28
SINGLESTEP
When this bit is set, a hardware trigger or a write to the START bit will launch
a single conversion on the next channel in the sequence instead of the
default response of launching an entire sequence of conversions. Once all of
the channels comprising a sequence have been converted, a subsequent
trigger will repeat the sequence beginning with the first enabled channel.
Interrupt generation will still occur either after each individual conversion or
at the end of the entire sequence, depending on the state of the MODE bit.
0
29
LOWPRIO
Set priority for sequence A.
0
0
Low priority. Any B trigger which occurs while an A conversion sequence is
active will be ignored and lost.
1
High priority.
Setting this bit to a 1 will permit any enabled B sequence trigger (including a
B sequence software start) to immediately interrupt this sequence and
launch a B sequence in it’s place. The conversion currently in progress will
be terminated.
The A sequence that was interrupted will automatically resume after the B
sequence completes. The channel whose conversion was terminated will be
re-sampled and the conversion sequence will resume from that point.
30
MODE
Indicates whether the primary method for retrieving conversion results for
this sequence will be accomplished via reading the global data register
(SEQA_GDAT) at the end of each conversion, or the individual channel
result registers at the end of the entire sequence.
Impacts when conversion-complete interrupt/DMA triggers for sequence-A
will be generated and which overrun conditions contribute to an overrun
interrupt as described below:
0
0
End of conversion. The sequence A interrupt/DMA flag will be set at the end
of each individual A/D conversion performed under sequence A. This flag will
mirror the DATAVALID bit in the SEQA_GDAT register.
The OVERRUN bit in the SEQA_GDAT register will contribute to generation
of an overrun interrupt if enabled.
1
End of sequence. The sequence A interrupt/DMA flag will be set when the
entire set of sequence-A conversions completes. This flag will need to be
explicitly cleared by software or by the DMA-clear signal in this mode.
The OVERRUN bit in the SEQA_GDAT register will NOT contribute to
generation of an overrun interrupt/DMA trigger since it is assumed this
register may not be utilized in this mode.
Table 281. A/D Conversion Sequence A Control Register (SEQA_CTRL, address 0x4001 C008) bit description
Bit
Symbol
Value
Description
Reset
value