Grand Central on-board ADC resolution?
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- melinajefferson12
- Posts: 4
- Joined: Tue Feb 28, 2023 5:34 pm
Grand Central on-board ADC resolution?
Hi, maybe I'm missing something obvious but what's the on-board ADC resolution for the Grand Central's 15 analog pins? It's not explicitly stated but some code in the learning page (https://learn.adafruit.com/adafruit-gra ... -analog-in) uses 2^16 as a divider but then other pages that say the SAMD51 only have 12-bit resolution (https://learn.sparkfun.com/tutorials/sa ... and-output). The onboard DAC is explicitly stated to be 10-bit so I thought it was kind of odd that the ADC wasn't also explicit. Thanks in advance!
- melinajefferson12
- Posts: 4
- Joined: Tue Feb 28, 2023 5:34 pm
Re: Grand Central on-board ADC resolution?
For some more context to the above: I am hoping to use this board to read in several 4-20 mA sensors which I'll convert to likely 0.6-3 V with a high-accuracy 150 ohm resistor. I have accuracy specs on my sensor and I would like to confirm that the resolution I can achieve from the ADC on the board will be greater than or equal to the resolution I can get from the sensor directly. From my calculations, I need at least 12-bit resolution from the ADC to ensure this, without having to go to external ADC boards (which I'm trying to avoid just to keep the system as simple as possible)
- adafruit_support_bill
- Posts: 88039
- Joined: Sat Feb 07, 2009 10:11 am
Re: Grand Central on-board ADC resolution?
It has 12-bit analog inputs and 10 bit analog outputs. But CircuitPython 'normalizes' everything to 16 bit resolution for portability between processors.
- melinajefferson12
- Posts: 4
- Joined: Tue Feb 28, 2023 5:34 pm
Re: Grand Central on-board ADC resolution?
Ah ok that makes more sense with the documentation I was seeing. So just to confirm, using circuit python, pin.value would return integers from 0 to 65536 in steps of 16 then?
- adafruit_support_bill
- Posts: 88039
- Joined: Sat Feb 07, 2009 10:11 am
Re: Grand Central on-board ADC resolution?
That is correct.
- melinajefferson12
- Posts: 4
- Joined: Tue Feb 28, 2023 5:34 pm
Re: Grand Central on-board ADC resolution?
Great thanks so much!
Please be positive and constructive with your questions and comments.