[Arm-netbook] laptop 15in pcb3

[Luke Kenneth Casson Leighton]

i'm on to assembly of pcb3, now, which is the power / charger board.
pcb assembly whilst listening to ozric tentacles is a thoroughly
recommended experience btw :)

this one is slightly fiddly because it's not a "prototype" PCB, so is
not covered with as much solder (on the pads).  things aren't properly
sticking unless i "pre-tin" them.  the LTC4155 QFN i wicked its pads
across a soldering iron and that has gone down fine: 0402 resistors
however are _really_ acting up.  next time i will go round every
single pad with a soldering iron, blobbing them before even
considering putting components on.


regarding PCB2: the SPI interface to the LCD, i've given up on the
current approach, because of the two "unknowns" - unknown hardware and
unknown software - and have asked the sponsor to obtain an adafruit
HX8357D LCD and an arduino.  i will then be able to work from two
"known-goods", as a way to triage which (or if both) of the two
"unknowns" is "not working".

there are slight differences between the yunlea LCD and the adafruid
LCD, which i will be able to compensate for by: (a) getting the
adafruit LCD working with the STM32F072 and (b) getting the arduino to
talk to the yunlea LCD.  having these successfully cross-talk i will
then be in a position to finally put the yunlea LCD onto the
STM32F072.  that's the plan, anyway.

l.