UM10850
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 2.4 — 13 September 2016
359 of 464
25.1 How to read this chapter
The ADC controller is available on all parts. The number of ADC channels available is
dependent on the package size.
25.2 Features
•
12-bit successive approximation analog to digital converter.
•
Input multiplexing among up to 12 pins.
•
Two configurable conversion sequences with independent triggers.
•
Optional automatic high/low threshold comparison and “zero crossing” detection.
•
Measurement range V
REFN
to V
REFP
(typically 3 V; not to exceed V
DDA
voltage level).
•
12-bit conversion rate of 5 MHz. Options for reduced resolution at higher conversion
rates.
•
Burst conversion mode for single or multiple inputs.
•
Synchronous or asynchronous operation. Asynchronous operation maximizes
flexibility in choosing the ADC clock frequency, Synchronous mode minimizes trigger
latency and can eliminate uncertainty and jitter in response to a trigger.
25.3 Basic configuration
The ADC may be utilized entirely via the ADC API (available from NXP), or by directly
controlling the registers of the ADC.
Configure the ADC as follows:
•
Clear the PDEN_ADC0 bit in the PDRUNCFG register (
) in order to enable
the analog portion of the ADC.
•
Set the ADC0 bit in the AHBCLKCTRL0 register (
) to enable the clock to the
ADC0 register interface and the ADC0 clock.
•
Clear the ADC0 peripheral reset using the PRESETCTRL0 register (
•
The ADC block creates four interrupts which are connected to slot #26
(ADC0_SEQA), slot #27 (ADC0_SEQB), slot #28 (ADC0_THCMP and ADC0_OVR)
in the NVIC. The sequence interrupts can also be configured as DMA triggers through
the INPUT MUX (see
) for each DMA channel and as inputs to the SCT.
•
Use IOCON (
) to connect and enable analog function on the ADC input
pins.
•
Calibration is required every time the ADC is powered off, unless offset error is not a
concern and the BYPASSCAL bit in the CTRL register is set. Calibration would be
done (at a minimum) after power-up or wake-up from a reduced power mode where
the ADC was turned off to save power. Re-calibration is also recommended if the
temperature or voltage operating conditions have changed (including if the chip has
UM10850
Chapter 25: LPC5410x 12-bit ADC controller (ADC0)
Rev. 2.4 — 13 September 2016
User manual