The boards came in yesterday...

I put one together hooked it up and poked it a little, and it looked like it was in the static sense working. I programmed the uC with the same code as I had on the previous board, and after a short while, I got "the smell". So I flipped the power switch (the hand is never far from it during early development) and started to think about it...

So I figured out my PWM issue...

The PWM control registers have a feature that requires them to be "unlocked" before writing to them. There is a config bit that turns the feature on and off. Needless to say, I flipped the configuration bit and it started working.

At the moment I am configured for 9 bit resolution, from the scope, that gives me 76kHz, if that isn't fast enough then I will go to 8 bit, and double the frequency, but that's something to look at once I understand how the regulator section responds.

After a long break during which time I designed a buck-boost section for the circuit board, and took a vacation. I am back onto the project.

So once i realized the necessity of the buck boost I went about drawing the circuit and laying out the board, with the help of various websites I got the circuit mostly done. Then came the need to calculate the necessary capacitors and inductors... The numbers I came up with were HUGE! I means really big! and big things usually come with a big price tag. I really needed to get them under control.

With the prospect of implementing a "2-switch" non-inverting buck boost DC-DC converter, I started to redesign the board, which involves choosing the n channel FETs, and a high/low side driver for them, the Schottky diodes and most importantly the energy storage elements (an inductor and a capacitor).

At the weekend I picked up the courage to plug the PWM filter connectors into the voltage control on the module, and it appeared to work, dialing the PWM output higher caused more voltage to come out, turning it down caused less. Yet there were problems...