I added a 0.1uf cap to the mini54 VDD (as its on a extra pcb just to be nice) Same with MK20 reset_b does not seem to be pulled high or low any where? (internal pullup?) The mini54lan has a reset line that just seems to be floating (pin 3) does this need to be pulled up or down? Paul and every one else just leave it floating.

I have a 0.1uf decoupling cap per VDD pin on the MK20 does the VDDA need a 0.1uf cap as well? (I am not using analog) VBAT (what is its actual purpose?) I have just tied it to VDD. I have just tied VDDA to VDD and VSSA to GND, I have tied VREFH to VDD and VREFL to GND and finally VREF_OUT to GND through a 0.1uf cap is this all ok? I have removed the i2c lines between the mini54 and mk20 because I read some where paul wrote they are not needed. Do I need extra decoupling? or is the 2.2uf cap ok? We usually assume usb 5v will be pretty stable? But the 5v source for this project could be any psu which may not be that stable? Should I be adding extra smoothing to my 5v in? My design will be powered from a external 5v psu NOT usb. My question is do I need the x2 20pf caps? Or can you get 16mhz through hole crystals that will work correctly with the teensy by them self? I have gone for using a older through hole crystal as I do plan of this being a production board and prices on smd crystals seem to be very expensive. I have seen a few people have made custom boards and would really appreciate it if you could have a quick look at my schematic and check to see if I have made any mistakes or if you have any concerns? second set of eyes is always better then one! If it all looks good i will start creating the pcb and get a prototype made.

But I will ask them again just to confirm I understood the answers correctly. I have done quite a lot of research on this forum hunting down answers for different questions I had when designing this and i did find most of them.

Circuitmaker pcb