Peripherals—IP2022 User’s Manual 294 www.ubicom.com configured as either an input or an output depending which device
is slower and has a need to stall incoming data. 4.7 Analog to Digital Converter (ADC) The on-chip A/D converter has the following features: • 10-bit ADC, ½ LSB accuracy • 8 input channels • 48 kHz maximum sampling rate • One-shot conversion. • Optional external reference voltage • Vmax = AVdd (max 2.7V) • Result returned in the ADCH and ADCL registers Figure 4-13 shows the A/D converter circuitry. The ADC input pins
use alternate functions of the Port G pins. The result of an ADC
sample  is  the  analog  value  measured  on  the  selected  pin.  To
correctly read an external voltage, the pin being sampled must be
configured as an input in the port direction register (i.e. the RGDIR
register). If the pin is configured as an output, then the result will
indicate the voltage level being driven by the output buffer.