The ADC on ATtiny861 has an external reference of 2.5V, and with 10-bit ADC, this gives a resolution of 2.44mV. The voltage input to the ADC is scaled down 8x, so max voltage possible to measure is 19.98V, and resolution is 19.5mV. The current input uses the differential input with 20x gain over a shunt resistor of 0.5Ω. This is also scaled down 8x, thus giving a resolution of 1.95mA, so max current possible to measure is 2A. The PWM output to the buck converter has 512 values, which means a resolution of "Input Voltage" divided by 512, e.g. at 10V input the resolution will be approximately 19.5mV.

Note: The battery cell voltage reported in the SB200 PC application may vary during
charging. This is because the Charger is continually adjusting the voltage
to match the voltage and current limits set.