We use the built-in CircuitPython library called analogio for analog output (as well as input). There are two pins on the SAMD51 capable of digital-to-analog conversion (DAC), one of which is convenient to access from the GPIO header below the microcontroller.

PyCubed's most accessible digital-to-analog converter pin.

⚙ Hardware Needed

• [ ] PyCubed mainboard

📚 External Libraries Needed

None

📑 Code

import board
import analogio

dac = analogio.AnalogOut(board.DAC0)

# DAC output is 16-bit value scaled from 0V to 3.3V
dac.value = 32768 # output 1.65V

How to scale a number into a range:

Our DAC output a voltage from 0V to 3.3V, but we need to scale that value into the appropriate 16-bit range:

def scale_vout(target_voltage):
    return int((target_voltage/3.3) * 0xFFFF)

print(scale_vout(1.65)) # would print 32767
print(scale_vout(1)) # would print 19859
print(scale_vout(2)) # would print 39718

Using our scale_vout helper function with the above analogio example:

import board
import analogio

def scale_vout(target_voltage):
    return int((target_voltage/3.3) * 0xFFFF)

dac = analogio.AnalogOut(board.DAC0)

dac.value = scale_vout(1.65) # output 1.65V

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