[sdiy] Ever have one of those days?

[Tim Ressel]

I have. 

First failure: my glorious attempt to make a board that would take an octave of TOG square waves and create an octave of sine waves. It turns out you can't cascade CD4018s without an inverter between them.

And then I find out I missed a rather important bit of info on the CPLD datasheet: the parts are 1.8V, not 3.3V. This means the latest TOG boards are scrap. A rather expensive mistake. 

However it is important to look for the good in the bad. The 4018's are pricey enough that if you put 26 of them on a board it gets so costly that a CPLD makes more sense ($1 less, 25 less parts to place). That design will probably go in that direction. The TOG board needed one more spin anyway, so I add a regulator and all is well. Also someone suggested the clock divider can go inside the CPLD. Saves real estate and a 4024. 

The sun is out. Perhaps today will be better.

--TimR