3.3.1 ADC Input Selection

Vbg (VREF) can be selected as the ADC input per the table below from the MUXPOS registers of the ADC at ATtiny817.

Table 3-3. ADC Input Selected
ValueDescription
0x0AIN0
0x1AIN1
0x2AIN2
0x3AIN3
0x4AIN4
0x5AIN5
0x6AIN6
0x7AIN7
0x8AIN8
0x9AIN9
0x10AIN10
0x11AIN11
0x1CDAC0
0x1DInternal reference (from VREF peripheral)
0x1ETemperature sensor
0x1F0V (GND)
OtherReserved

The value of the Vbg (VREF) can be selected per the table below from CTRLA register of the VREF at ATtiny817.

Table 3-4. Vbg Reference Value selected
ValueDescription
0x00.55V
0x11.1V
0x22.5V
0x34.3V
0x41.5V
otherReserved

In this design, Vbg (1.1V) is selected as the input of the ADC for easier calculation.