I want to make some precise measurements with Arduino Due. Although I'm using very good external voltage reference (LTC6655) measured data is still jumping around, especially significant when I'm trying to measure low voltages (0.1-0.05V). Can I improve ADC accuracy by changing it's settings?

The default Arduino Due ADC settings are:

```
// Initialize Analog Controller
pmc_enable_periph_clk(ID_ADC);
adc_init(ADC, SystemCoreClock, ADC_FREQ_MAX, ADC_STARTUP_FAST);
adc_configure_timing(ADC, 0, ADC_SETTLING_TIME_3, 1);
adc_configure_trigger(ADC, ADC_TRIG_SW, 0); // Disable hardware trigger.
adc_disable_interrupt(ADC, 0xFFFFFFFF); // Disable all ADC interrupts.
adc_disable_all_channel(ADC);

```

So, with `adc_init` we can configure frequency and startup time. And with `adc_configure_timing` we configure tracking time, settling time and transfer time. But how to select those values? Does increasing of that times improves precision?

Useful links:

[Datasheet](http://www.atmel.com/Images/Atmel-11057-32-bit-Cortex-M3-Microcontroller-SAM3X-SAM3A_Datasheet.pdf) - ADC description starts on page 1317.

[Atmel Software Framework](http://www.atmel.com/tools/avrsoftwareframework.aspx) - see adc.h and adc.c.