Analog inputs on the N+

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

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.

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

I finally posted a series of results about the ADC noise and how to attenuate it.
Hope it helps.
Cheers

How do you switch the analog inputs from digital to analog?

How do you switch the analog inputs from digital to analog?

It's a matter of what you declare first:

// 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);