There are a total of 24 inputs (slots) multiplexed to the AUX ADC (Figure 8-5). All inputs are measured in round robin fashion (Figure 8-6). Each input takes 8 μs (nominal) to measure and a single round robin cycle completes in 192 μs (nominal). The inputs to AUX ADC are:

• Die temperature 2
• Multiplexed differential AUX_n–1 to AUX_n (AUX1 to AUX4), where n = 1 to 4
• MISC measurements:
  • PWR pin
  • REFL, internal reference
  • VBG2, internal bandgap
  • VCM1, coomon voltage on Main ADC
  • AVAO_REF, always-on block reference
  • AVDD_REF
  • OV DAC from OV protector
  • UV DAC from UV protector
• Multiplexed GPIO1 to GPIO8
• Spares (RSVD)

All measurements are reported in 16-bit hexadecimal in 2s complement. Results are reported to the corresponding *_HI (high-byte) and *_LO (low-byte) registers. It first converts the hexadecimal results to decimal values. Follow the equations in Table 8-4 to translate the result to μV or °C.

When the AUX ADC is enabled, all AUX ADC related result registers shown in Table 8-4 are reset to the default value 0x8000. The measured result is populated to the result registers as the AUX ADC makes its conversion along the round robin cycle. When MCU reads the *_HI register, the device will pause the data refresh to the associated *_LO register until that *_LO register is read.

Figure 8-5 AUX ADC Measurement Path

Figure 8-6 AUX ADC Round Robin Measurements