--------- ask-1w-001 ---------

- hardware feature overview -

* provides software bitbanged 1-wire master
* 2n7000 level shifted from 3.3v to 5v
* downstream port is 3.5mm trs audio
* +5v power supply, current limited to
  50ma by ptc fuse
* green power led, on = normal operation,
  off = output is shorted out


--- expansion port i/o usage ---

ground
+5v
+3.3v
io (h3 gpio pa01)


--- 1-wire downstream port ---

tip    +5v vcc
ring   1-wire data
shield ground