# Analog to Digital Conversion

## Analog vs. Digital

• Analog: infinite variations / states
• Digital: discrete (or finite) states
• How do we represent infinite variations in a system that has limited / finite values?

## Analog to Digital Conversion

• Argon is a digital system so we need to convert the infinite analog input to a discrete values
• The sampling frequency is how many times per second
• The resolution is how many bits are used to store the voltage
• Higher resolution means greater detail, but also more bits (more memory)

## Understanding Resolution  • Blue line is the digital sample value (just a number with no units)

## Argon ADC Resolution is 12-bits

• There 2^12=4096 possible values (think “buckets”)
• In Binary
• 0 = 000000000000
• 4095 = 111111111111

• The range of analog voltage is 0v to 3.3v
• The range of digital values is 0 to 4095
• Q: How many digital values per 1v?
• Q: How many volts per each digital value?
• Q: If there is 3.3v on an analog input, what is the value of `analogRead()`?
• Q: If there is 1.67v on an analog input, what is the value of `analogRead()`?

## Exercise • Connect potentiometer to analog pin A0
• Connect LED to digital pin D2 (do we a pin with PWM?)
• Control LED brightness with potentiometer

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