Hi,
I remember someone saying here that the analog input pins of the N+ are unreliable if there's an ethernet cable plugged in - to what extend does that happen and what are the symptoms (loss of a few bits of precision, or mostly right readings and some completely bogus ones, or ...) and is that valid for all the analog pins? Is it also valid if the pins are not used in analog mode (but for e.g. I2C)?
Also, is the 3.3V limit on the analog ports valid if they are in analog mode or also when they are used for other purposes (e.g. I2C), as is my guess?
Regards,
Stefan
Analog inputs on the N+
Started by Stefan W., Sep 16 2011 07:51 PM
5 replies to this topic
#1
Posted 16 September 2011 - 07:51 PM
I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.
-- H.L. Mencken, "What I Believe"
-- H.L. Mencken, "What I Believe"
#2
Posted 17 September 2011 - 02:27 AM
Also, is the 3.3V limit on the analog ports valid if they are in analog mode or also when they are used for other purposes (e.g. I2C), as is my guess?
Can't speak to your first question (analog accuracy with/without Ethernet connected). As for the second question, I'm pretty sure I've read that the 3.3v limit applies when pins are in analog mode but NOT when they're in digital mode. I.e. any pin in digital mode is 5v tolerant. I think this means that it's the ADC that can't handle more than 3.3v but that the ADC is "out of the loop" when the pin is in digital mode. Hopefully somebody will verify my assertion.
#3
Posted 17 September 2011 - 02:58 AM
The analog pins are 5V tolerant when used in digital mode (including during boot). When used in analog mode, they can accept voltages of ~0V to ~3.3V.
Chris
#4
Posted 16 October 2011 - 06:50 PM
I finally posted a series of results about the ADC noise and how to attenuate it.
Hope it helps.
Cheers
Hope it helps.
Cheers
Biggest fault of Netduino? It runs by electricity.
#5
Posted 17 October 2011 - 05:34 AM
How do you switch the analog inputs from digital to analog?
#6
Posted 17 October 2011 - 05:38 AM
It's a matter of what you declare first:How do you switch the analog inputs from digital to analog?
// Declares pin A0 as analog input AnalogInput Input = new AnalogInput(Pins.GPIO_PIN_A0); // Declares pin A0 as digital input InputPort Input = new InputPort(Pins.GPIO_PIN_A0, false, Port.ResistorMode.Disabled);
"Fact that I'm a moderator doesn't make me an expert in things." Stefan, the eternal newb!
My .NETMF projects: .NETMF Toolbox / Gadgeteer Light / Some PCB designs
My .NETMF projects: .NETMF Toolbox / Gadgeteer Light / Some PCB designs
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