There are total of 24 inputs (slots) multiplexed to the Main ADC (Figure 8-1). All inputs are measured in round robin fashion (Figure 8-2). Each input takes 8 μs (nominal) to measure and a single round robin cycle completes in 192 μs (nominal). The inputs to the Main ADC are:

• Die temperature 1
• TSREF
• VS1 to VS16 voltages through differential VS_n–1 to VS_n, where n = 1 to 16
• CSADC_AUX input through differential SRP–SRN pins
• Multiplexed GPIO1 through 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. First, convert the hexadecimal results to decimal values. Follow the equations in Table 8-1 to translate the result to μV or °C.

When the Main ADC is enabled, all Main ADC-related result registers shown in Table 8-1 are reset to the default value 0x8000. The measured result is populated to the result registers as the main 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 8-1 Main ADC Measurement Path

Figure 8-2 Main ADC Round Robin Measurements