User manual

...the world's most energy friendly microcontrollers
2012-04-24 - Giant Gecko Family - d0053_Rev0.96 680
www.energymicro.com
28 ADC - Analog to Digital Converter
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ADC
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Quick Facts
What?
The ADC is used to convert analog signals
into a digital representation and features 8
external input channels
Why?
In many applications there is a need to
measure analog signals and record them in
a digital representation, without exhausting
your energy source.
How?
A low power Successive Approximation
Register ADC samples up to 8 input channels
in a programmable sequence. With the help
of PRS and DMA, the ADC can operate
without CPU intervention, minimizing the
number of powered up resources. The ADC
can further be duty-cycled to reduce the
energy consumption.
28.1 Introduction
The ADC is a Successive Approximation Register (SAR) architecture, with a resolution of up to 12 bits
at up to one million samples per second. The integrated input mux can select inputs from 8 external
pins and 6 internal signals.
28.2 Features
• Programmable resolution (6/8/12-bit)
• 13 prescaled clock (ADC_CLK) cycles per conversion
• Maximum 1 MSPS @ 12-bit
• Maximum 1.86 MSPS @ 6-bit
• Configurable acquisition time
• Integrated prescaler
• Selectable clock division factor from 1 to 128
• 13 MHz to 32 kHz allowed for ADC_CLK
• 18 input channels
• 8 external single ended channels
• 6 internal single ended channels
• Including temperature sensor
• 4 external differential channels
• Integrated input filter
• Low pass RC filter
• Decoupling capacitor
• Left or right adjusted results
• Results in 2’s complement representation
• Differential results sign extended to 32-bit results