Let's get physical...

It didn't take too long to come up with a schematic...

The PCB took a lot longer.  Designing when tight for area is always tricky, but imposing restrictions like 2 layer does not help... I eventually ended up with a design I was reasonably happy with and sent it off to Beta Layout to be produced via. their PCB Pool service.  Beta offer great turnaround times (if there are no issues), but their boards are 1oz and really don't enjoy hand soldering much, in my experience... the tracks lift quite easily, so require considerable care.

The best solution to this is take advantage of the fact you get a certain minimum area of board, so can have some spares.  A few days wait, and then rev00 showed up in physical form...

... for your protection... less kaboom...

Out of the packet...

Beta give you a "free" stencil with your prototyping designs, which is very nice when you have the tools... particularly when dealing with pain in the backside packages like the LT3494 and the ADXL335.

I quickly started assembling the boards... it went well at first, only to realise I'd put entirely the wrong footprint on for the LT3494.  Arghhhh!

 

Target had a footprint for DFN, which I'd used, but the orientation of the pins was at 90 degrees to what the LT3494 used.  Okay... so at this point I knew there would almost certainly need to be a rev01... and was reminded of an important lesson from Dave Jones... always check your footprints, or better, design your own.

No matter, I can still get it up and running.  My first attempt didn't go so well... the tiny tracks were damaged beyond repair on the first attempt, trying to find a way to wire all the pins on that would keep the footprint flat to the board.

Another go, and I found it was best to just give up on mounting it flush and instead put the part at a right angle to the board, wiring the long ground pad to ground with a short wire, which could also offer some structural support.

Okay... so now we're getting somewhere... let's populate the rest of the board...

  

Great... the power seems to be working fine (after a slight mod to route it correctly, see if you can spot it in the pic)... and all the rails seem okay.  Let's try attaching the screen and programming it...

It works! (please excuse the blurriness)... great news... but the ADC test is producing funny results for the accelerometer.  Looks like there may may some other issues to fix... roll on rev01...