There are 7 analog inputs on the BeagleBone.
- 12 bits (Output values in the range 0-4095)
- 125ns sample time
- 0-1.8V range (do not exceed!)
- 2 uA current flows into the ADC pin in this range
- If using a voltage divider, the lower leg (the one connected to ground) should be <= 1k Ohm
- Since we are measuring millivolts, resistors with 0.1% error tolerance should be used in a voltage divider.
- There is a 1.8V reference voltage VDD_ADC at Port 9 Pin 32.
- There is a GNDA_ADC that should be grounded on Port9 Pin 34.
The ADC values can be read very easily:
Original BeagleBone, later builds:
beaglebone:~# cat /sys/devices/platform/omap/tsc/ain1
Original BeagleBone, older builds:
beaglebone:~# cat /sys/devices/platform/tsc/ain1
FIrst enable the ADC ports, then find out where they are and finall read them: