Jun 102017
 

So, I haven’t yet tried out the MOSFET outputs, but nearly all the GPIO inputs work. I say nearly… there is one that doesn’t on channel 4.

I can test by shorting out the 0V and GPIO pins with a multimeter probe. Not sure why one channel isn’t working yet, that I’ll have to debug tomorrow.

It is worth noting that the MC14066s here are older than I am if I am reading the date codes correctly. Still, they’ve been kept in a tube all these years, so no reason why they’d suddenly pop. More probable, I’ve goofed somewhere in the wiring of this.

At worst, I should be able to de-solder the faulty chip (if that is the case) and put another one in its place… I have plenty lying around. The fact that its mate on the other side is working fine, is promising.

The up side is this board doesn’t look like a big mess of wires like the last prototype. Once I get the faulty channel sorted, I should be able to make the I/O modules that will provide the MOSFET outputs, ESD protection and switch debouncing.

One thing I’ll probably do in future: use bigger vias for my jumper wires, and actually mark on the silk screen component values and the jumper wire routes.


Did some probing… turns out my jumper wire wasn’t making good contact with the via … a dry joint. Definitely I’ll make the vias bigger next time!