XC-1A mystery headers: H20, H21, H22

[Gravis]

i was checking out the bottom of my XC-1A and found there are some undocumented PTH holes where you can add some header pins.

H20 - 4 holes right by the USB port
H21 - 2 holes by "X1PortA"
H22 - 2 holes by "D36" (X0D36) and "D37" (X0D37) on the "Prototyping Area"

i'm very interested in them because i need all the 1 bit ports i can get. (no, i cannot solder to the LEDs as that can only be done by very skilled people with the proper equipment.)

[DrNO]

H22: Looks like a PLL lock indicator
H21: Crystal output
H20: Direct Connection to USB pins (square one is V+ and then pin 2, 3, and 5 of the USB port)

Check the XC-1A Schematic PDF and just search for those three keywords and you can see how they're conencted.