All, I'm designing a Teensy 3.6 "Pro" to enable access to all of the Teensy 3.6 pins and provide better packaging for placement directly in a final product. This is a project that I'm doing, but I'd like to make it available for sale through my
startup as well. The goal is to have about a 30 x 30 mm board with the MK66FX1M0. I'm hoping that I can fit a micro USB connector on board and both the 16 MHz and 32.768 kHz crystals. My plan is to have castellations on the board edges and through holes available inboard for 1mm spaced pins. This would give the option to reflow the board to a daughter board or to hand solder pins for those that would rather hand solder. The programmer would be on the daughterboard along with any other sensors, connectors, or peripherals.
Attached is a preliminary schematic. A few things to note:
1. The circuit can be powered by either the onboard micro USB or an external input (VREG_IN1) - the MK66FX1M0 has a built in regulator up to 5.5V.
2. VBAT can be supplied externally, otherwise power is from VDD.
3. Right now, I'm at 29 connections per board side, which should fit...
Any feedback in terms of the design approach or schematic would be greatly appreciated!
Thanks,
Brian