[Open_electroporator] pyflex_f401 v0.5 --> v0.6 testing

[John Griessen]

On 04/25/2018 12:16 PM, John Griessen wrote:
> So, after losing that last assumption I checked USB_VBUS while plugging my  laptop port in and saw the current change
> on my lab supply since the laptop was starting to supply more when plugged in.  The voltage at that port was just 0.05V
> when plugged in!  So some of my switching circuitry needs taking apart with a hot air gun and tweezers and get USB working, then 
> fix some way to send it for testing in a square plastic box.  This step could be in 3 more days now.

The low volts for USB_VBUS was caused by a connector leg not soldered all the way.  Fixed the problem on the prototype and
extended the solder lands longer on the connector footprint and fitted that into the layout for next time, v 0.6.

Some mentions of USB_VBUS detecting, and also losing my assumptions, got me to looking at the input to the USB_VBUS detecting
pin and it was at 2.1V while the MCU was powered by 2.98V, which might have worked, and might not....so I undid a resistor 7.5k
and put a 1.8k and penciled it on the v0.5-->v0.6 paper schematic and turned it on and the USB port "enumerated" as they say about 
USB in USB-land.

So now all the usual features of a G30TH are working and with power converters and switches that will be very useful soon.
I'm going to make a testing issue of 2 units as-is with "wire mods" to connect things one way -- putting off the switching of 
power sources for later.

Could be ready to send one out in 2 days.  Yay!  Frustration about over.