v0.2 bringup

I’ve started soldering the v0.2 board, testing and porting the v0.1 software as I go along.  The LED, button, and ADC channels all moved, which required adjustment of a couple of header files.  Two minor wire mods were required, but so far everything tested is working.  There is a tiny bit of coupling between the PWM signal and the ADC feedback signal, but I suspect a well placed capacitor will clean the line up.

From here, I have to do the following:

1. Populate the auxiliary transformer and generate a sane voltage rail for the opamps on the secondary side.
2. Populate the feedback circuitry.
3. Adjust the ADC driver to use the new configuration.
4. Calibrate.

And then I can test my primary side current monitoring.

Current monitor

My boards arrived from PCBtrain a few weeks ago, so you’d expect enthusiastic assembly to ensue. However,  most of my time is going into finding a job, so I’ve made relatively little progress. I started with the current monitor, to see what it feels like when assembled – so far I’m very happy.  It’s just like a slightly heavier memory stick.

The ATtiny does what it should, the LCD can display what I tell it to, and the switch works fine too.  Currently I’m recalculating the resistor values for current measurement, as I seem to have made the gain optimistically small. A similar measurement circuit is used in the power supply, so this provides a clean space to make sure it words exactly as designed.