7.3.5 Oscillator and Timing Control

The device uses one of the two internal oscillators (Low Power Oscillator or High Speed Oscillator) for converting the analog input voltage into a digital output code.

The steps for selecting the oscillator and setting the sampling speed are listed below:

1. Select the Low Power Oscillator (OSC_SEL = 1b) to monitor slow moving signals(< 300 Hz) at extremely low power consumption and sampling speeds (< 600 SPS). Select the High Speed Oscillator (OSC_SEL = 0b) to scan the sensor signals with faster sampling speed (> 50 kHz).
2. Set sampling speed by programming the nCLK register:

Equation 2.

where

• f_s = Sampling Speed
• Oscillator Frequency = 1/t_HSO or 1/t_LPO depending on the OSC_SEL bit, refer the Specifications for 1/t_HSO or 1/t_LPO.
• nCLK is number of clocks in one conversion cycle (nCLK register)