I just purchased an ARPI600 expansion board for my raspberry pi 3b. I wanted this board because it acts as an i/o expansion and allows the rpi to control arduino shields. I have seen this card recommended by many people which is why I was incredibly surprised to see that the documentation for it is ridiculously underwhelming.
It gives information about how to setup the serial debugging function without telling you what it is pretty why you would want it. It tells you how to control the ARPI600 with the pi but does not give you any direction as to what or why. There is little to no documentation on the various pins and jumpers implemented. Most of all I am confused about how to provide power to the ARPI600. I am under the impression it receives a 5v current from another source as the pi can only provide a 3v. But as usual there is no documentation to suggest otherwise or confirm my suspicion. So now I have it all hooked up to the rpi but I am afraid to turn it on for fear of shorting it out or something.
I know that based on the popularity of the product someone has an idea of what their doing but no one with the knowledge has posted anything online. If there is anyone with experience configuring the ARPI600 please let me know. If you just search ARPI600 on Google and you will find the operators manual and see what I mean about the documentation.