UM10850
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 2.4 — 13 September 2016
363 of 464
NXP Semiconductors
UM10850
Chapter 25: LPC5410x 12-bit ADC controller (ADC0)
25.5 General description
The ADC controller provides a great deal of flexibility in launching and controlling
sequences of ADC conversions using the associated 12-bit, successive approximation
ADC converter. ADC conversion sequences can be initiated under software control or in
response to a selected hardware trigger.
Once the triggers are set up (software and hardware triggers can be mixed), the ADC runs
through the pre-defined conversion sequences converting a sample whenever a trigger
signal arrives until the sequence is disabled.
The ADC controller uses the system clock as a bus clock. The system clock or the
asynchronous ADC clock (see
) can be used to create the ADC clock which
drives the successive approximation process:
•
In the synchronous operating mode, this ADC clock is derived from the system clock.
In this mode, a programmable divider is included to scale the system clock to the
maximum ADC clock rate of 80 MHz.
•
In the asynchronous mode, an independent clock source is used as the ADC clock
source without any further divider in the ADC. The maximum ADC clock rate is
80 MHz as well.
In this mode, the ADC clock frequency must not exceed ten
times the system clock.
A fully accurate conversion requires 15 ADC clocks.
Fig 57. ADC block diagram
1:0
3:2
15
CONVERSION
TRIGGER
DATA
REGISTERS
THRESHOLD
COMPARE
CHANNEL
and
SEQUENCE
CONTROL
ADC0_THCMP_IRQ
sequence A/B
complete IRQ
data overrun IRQ
ADC0_[0:11]
start
conversion
channel
select
ANALOG-to-
DIGITAL
CONVERTER
channel 1:11
11
ADCn
ADC
result
ADC0_PINTRIG1:0
SCT0_OUTm
ARM_TXEV
2
NVIC
NVIC
NVIC
SCT0_INMUX