The ADS124S0x provides a means for monitoring both the analog and digital power supply (AVDD and DVDD). The power-supply voltages are divided by a resistor network to reduce the voltages to within the ADC input range. The reduced power-supply voltage is routed to the ADC input multiplexer. The analog (VANLMON) and digital (VDIGMON) power-supply readings are scaled by Equation 9 and Equation 10, respectively:
Enable the supply voltage monitors using the SYS_MON[2:0] bits in the system control register (09h). Setting SYS_MON[2:0] to 011 measures VANLMON, and setting SYS_MON[2:0] to 100 measures VDIGMON.
When the supply voltage monitor is enabled, the analog inputs are disconnected from the ADC and the PGA gain is set to 1, regardless of the GAIN[2:0] bit values in the gain setting register (03h). Supply voltage monitor measurements can be done with either the PGA enabled or PGA disabled via the PGA_EN[1:0] register. To obtain valid power supply monitor readings, the reference voltage must be larger than the power-supply measurements shown in Equation 9 and Equation 10.