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.