SAMD21G MCU Internal ADC vs External ADC

[jaishankarm]

Internal ADC vs External ADC

General topics to discuss with everyone.

Right now I build a DC power datalogger using SAMD21G Microcontroller.
Measuring

• Voltage range 0-40V with 0.01V step.
• Current range -5A to 5A with 0.001A step.

For measuring I used both Internal ADC external 15bit ADC(MCP3426A0).

External ADC 15bit gave accurate results with every first try with the help existing Arduino library.

Internel ADC with oversampling i set resolution of ADC to 15bit & i faced other issues but it is resolved now help of

Noisy ADC data from Xiao SAMD21

Hi @jaishankarm If you don't require a super high sample rate, you could try accumulating the result over a number of samples then averaging, to reduce noise. The code example below sets-up the ADC just like analogRead() on A0, however it's also configured to accumulate over 256 samples. This generates a 20-bit value which the ADC auto shifts to the right by 4 (divide by 16), giving a 16-bit result. Setting the AVGCTRL.ADJRES to 0x4, shifts the 16-bit value to the right by a further 4 bits, gi…

Both ADC producing same accurate results. (I don't concern about sampling time)

Now my final thoughts of this experiment below,
Even though the External ADC produce accurate very easily, with little extra effort we can MCU's ADC to equivalently performance as External ADC. So can use SAMD21G internal ADC and save cost of external ADC

SAMD21G Internal ADC will be good choice*

please provide your thoughts on this topics