BLINDINGLY FAST ADC FOR YOUR BEAGLEBONE

PRUDAQ by Jason Holt

Dual-channel simultaneously-sampled 10-bit ADC
Up to 20MSPS per channel (40MSPS total)

The BeagleBone's programmable real-time units (PRUs) make it possible to capture the 400Mbit/s sample stream into the BeagleBone's 512MB of main memory.

round robin on 4 channel is also possible, for example.

http://hackaday.com/2016/07/31/blindingly-fast-adc-for-your-beaglebone/

https://github.com/google/prudaq/wiki