BeagleBone Black ADC
The BeagleBone® Black hardware has six analog input pins (AIN0
to
AIN5
). Each analog input pin has a 12-bit analog-to-digital
converter (ADC) that converts the analog input voltage to a digital voltage
reading.
In addition to the six input pins, the BeagleBone Black hardware has power rail and ground pins (VDD_ADC
and GND_ADC
).
The function readVoltage
measures the voltage applied to an analog
input pin relative to the ADC ground pin (GND_ADC
). The ADC-driver
built into the Linux® kernel returns the voltage measurement converted to a double. The values
range from 0
V (GND_ADC
) - 1.8
V (VDD_ADC
).
Caution
Never connect a voltage greater than
1.8 V
across the ADC pins. Voltages greater than1.8 V
can damage the board.Always connect the negative (ground) side of a voltage source to
GND_ADC
. The ADC measures positive voltages only. A reversed connection can damage the board.