Analogue reference Voltage.

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Analogue reference Voltage.

Post by keithsloan52 » Tue Nov 08, 2016 12:59 pm

My understanding is that the Voltage references for Analogue ports are pin 2 and pin 3. If pin 2 is connected to LED1 does that not affect analogue voltage readings.

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Re: Analogue reference Voltage.

Post by EmbeddedMan » Tue Nov 08, 2016 3:10 pm

I believe, by default, we have the ADC voltage references set to 3.3V and GND (internally). This frees up as many analog inputs as possible for users to use.


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Re: Analogue reference Voltage.

Post by majenko » Tue Nov 08, 2016 3:23 pm

Yes, by default the analog references are set to VCC and GND internally. The Vref+ and Vref- pins of the ADC are sometimes available on a board's headers, and sometimes not. For boards with an Arduino-like footprint there is a dedicated AREF pin which is connected to the Vref+ pin. This is never connected to anything else. The Vref- pin may be available or it may not - check the manual for your chosen board, since they are all different.
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