Rainbow Electronics NUC120 - Manual (Page 49)

NUC120 Series DATA SHEET
Publication Release Date: May 31, 2010
- 49 - Revision V1.02
5.15 Analog-to-Digital Converter (ADC)
5.15.1 Functional Description
NUC1XX series contain one 12-bit successive approximation analog-to-digital converters (SAR A/D
converter) with 8 input channels. The A/D converter supports three operation modes: single, single-
cycle scan and continuous scan mode. There are two kinds of scan mode: continuous mode and
single cycle mode. The A/D converters can be started by software and external STADC/PB.8 pin.
Note that the analog input port pins must be configured as input type before ADC function is enabled.
5.15.2 Features
y Analog input voltage range: 0~Vref (Max to 5.0V).
y 12-bits resolution and 10-bits accuracy is guaranteed.
y Up to 8 single-end analog input channels or 4 differential analog input channels.
y Maximum ADC clock frequency is 16MHz.
y Up to 800kHz SPS conversion rate, conversion time is less than 1.25us.
y Three operating modes
- Single mode: A/D conversion is performed one time on a specified channel.
- Single-cycle scan mode: A/D conversion is performed one cycle on all specified channels
with the sequence from the lowest numbered channel to the highest numbered channel.
- Continuous scan mode: A/D converter continuously performs Single-cycle scan mode until
software stops A/D conversion.
y An A/D conversion can be started by
- Software write 1 to ADST bit
- External
pin STADC
y Conversion results are held in data registers for each channel with valid and overrun indicators.
y Conversion result can be compared with specify value and user can select whether to generate
an interrupt when conversion result is equal to the compare register setting.
y Channel 7 supports 4 input sources: external analog voltage, internal fixed bandgap voltage,
internal temperature sensor output and analog ground.
y Support Self-calibration to minimum conversion error.