Light Controller PCB Assembly

Received the PCB and started building it up.  Here is the blank PCB.

My usual bring up of a new design is to install the power section and the USB connector, then test the power for shorts and opens.  Once I see all of the power rails up and running I will move on to components.  This is to prevent any component waste..

Here I have installed the PIC18F25K50 and its supporting parts.

Just to the left of the processor is a pattern for a TAG-Connect programmer connection.  In these tight spaces, I find this is the best.  Since I usually use the HID Bootloader methodology, I use this connection once to load the bootloader and then use the USB interface for all loading and debugging (traditional printf statements).

Now it needs to be mounted so I can use it for programming.  This device was designed to sit on a 6x8 plate.  So I drill out the four corners with a #43 drill bit (2-56 body clearance).  I use the partial holes on the back side underneath the studs as guides.

 

This puts the holes in the center of the studs as this picture shows.

Next step is to assemble the PCB to the plate.  I use 1/8" ceramic spacers for minimal clearance and 1/2" long 2-56 flat head screws.   This can be problematic trying to keep the screws in place while trying to assemble the spacers, PCB and then the nuts, as this picture shows.  Two of the screws have popped out of their holes.

So once the 4 screws are in place, I place a another 6x8 plate on the bottom as shown here.  This forces the screws to be seated all the way and makes it a lot easier to mount the spacers and PCB.

This picture shows the mounting plate with screws and spacers ready for the PCB to be attached.  The other 6x8 plate is holding the screws in place.

And finally the PCB is attached.

Now it is on to programming.