‫Welcome to the potentiometer interface demonstration but the base is three board for this demonstration.
‫We have a potentiometer connected to an external breadboard with three 2.2 K ohm resistors and with
‫these resistors we are creating a voltage divider where we are taking the three point three bolts and
‫dividing it by three.
‫So we get down to approximately one volt and that is because the X A.D.C. on the core in the Artic seven
‫chip on the basis your board can only read voltages from 0 to 1 volt.
‫And with that being said we're putting 3.3 volts into the X ADC PMA port.
‫So we have to create a voltage divider so that when we're at 3.3 volts We're actually only output 1
‫volt.
‫And so what we'll do as I turn the potentiometer the ADC reading inside the Artic seven chip on base
‫3 board is being displayed in a BCT format on the 7 segment display.
‫And the ADC core on the Artic 7 is a 12 bit 8 of the converter.
‫So the maximum output it can have is four thousand ninety six.
‫And so right now we're at like 8 8 or 0 and that's just because you can't get exactly zero.
‫We're sampling so fast we're currently sampling at 200 thousand samples per second.
‫So it's happening so quickly.
‫They appear to all be lit up as I start to turn the potentiometer.
‫You can see the values start to change.
‫Now we're at like a 4 5 7 1 1 8 8.
‫And the last two values are sincerely significant values change so fast that it appears there are a
‫constantly.
‫And so if I keep turning up that showing the voltage is getting higher and higher and you can see the
‫corresponding ADC reading goes up as well.
‫And if I turn the other way it goes down and if I go all the way over we get up to approximately 3 9
‫8 8 and that's just because we do have some losses from the three point supply we are currently using
‫some across these resistors we're having here to do a voltage divider boom we turn all the way over
‫we'll get up pretty close and end and each board is going to be slightly different just due to the 3.3
‫regulations supply they have.
‫But you should see somewhere close to 4000 as your maximum on the potential on the ATC reading.
‫And that is the potentiometer interface running on the bases three all board.