UM10429
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© NXP B.V. 2010. All rights reserved.
User manual
Rev. 1 — 20 October 2010
140 of 258
16.1 How to read this chapter
The ADC is uses channels 0 to 4 on the LPC1102. Channels 5 to 6 are not pinned out.
16.2 Basic configuration
The ADC is configured using the following registers:
1. Pins: The ADC pin functions are configured in the IOCONFIG register block
(
).
2. Power and peripheral clock: In the SYSAHBCLKCTRL register, set bit 13 (
).
Power to the ADC at run-time is controlled through the PDRUNCFG register
(
).
16.3 Features
•
10-bit successive approximation Analog-to-Digital Converter (ADC).
•
Input multiplexing among 5 pins.
•
Power-down mode.
•
Measurement range 0 to 3.6 V. Do not exceed the V
DD
voltage level.
•
10-bit conversion time
≥
2.44
μ
s.
•
Burst conversion mode for single or multiple inputs.
•
Optional conversion on transition on input pin or Timer Match signal.
•
Individual result registers for each A/D channel to reduce interrupt overhead.
16.4 Pin description
gives a brief summary of the ADC related pins.
The ADC function must be selected via the IOCON registers in order to get accurate
voltage readings on the monitored pin. For a pin hosting an ADC input, it is not possible to
have a have a digital function selected and yet get valid ADC readings. An inside circuit
disconnects ADC hardware from the associated pin whenever a digital function is selected
on that pin.
UM10429
Chapter 16: LPC1102 Analog-to-Digital Converter (ADC)
Rev. 1 — 20 October 2010
User manual
Table 139. ADC pin description
Pin
Type
Description
AD[7:0]
Input
Analog Inputs.
The A/D converter cell can measure the voltage on any
of these input signals.
Remark:
While the pins are 5 V tolerant in digital mode, the maximum
input voltage must not exceed V
DD
when the pins are configured as
analog inputs.
V
DD
Input
V
REF
; Reference voltage.
