MK20DX256, Cortex M4, 72MHz
256K flash memory
64 K x 8 RAM
jack with through hole mounting case. It's robust.
3.3V regulator dedicated for VDDA.
ground return for VSSA
Resettable fuse and reverse polarity protection
diode installed to protect your laptop
- Buffered D13 LED indicator
- 32KHz crystal for RTC
- Easy-to-read pin labels include native
signal names for professionals.
- Reset can be available on the physical
pin 25 if the extra 6 pins are snapped off.
The reset signal is useful as a warm start for external peripherals, such as a TFT display.
- An on-board user button, D27 (PTC9),
available for DIY. Users only needs to solder a
interface header installed for debugging
SWD debugger and
programmer made by EVBplus LLC, part# BDM-SWD, for
- 13.2V max., 300mA LDO.
- Size 1.7" x 0.7", breakable to
1.4" x 0.7" for the Teensy 3.2 form factor.
source, license free if you make and sell it commercially.
- No warranty, either
express or implied, is given for the PCB. Agree
our terms before buying the PCB. No alteration on
silkscreens . We shall not be liable
for any claims, expenses, damages, and loss of profits,
opportunities or information arising from the use of
1) Large memory size
and supported by Freescale KDS
2) SWD interface
programming and debugging
3) Low cost SWD
programmer made by EVBplus LLC
4) Dual 3.3V
regulators and separate ground returns
If your circuits draw a large amount of current, it will
pull down the 3.3V voltage level and make ADC readings inaccurate. With
a separate 3.3V regulator, the VCCA and AREF will not be affected by
5) Lipo Charger can be added by DIY
just solder 3 components on the top layer in the
6-1. MCP73831 (SOT23-5)
6-2. JST connector (DigiKey #455-1749-1-ND)
6-3. 0805 LED
All other components of the Lipo charger circuit are already installed on the bottom
7) A user
button (D27, PTC9) can be added by DIY users on the top layer, just solder 2
It's open source,
you can make you own board license free.
Gerber files are available now.
The above bare PCB is available at OSHpark:
The PCB minimum specs for traces,
spacing, drill size and annular rings are 5mil/5mil/12 mil/6mil,
respectively. It exceeded Oshpark's specifications.
They still may be able to make it for you, otherwise you have to download the Gerber zip
file and find another low cost PCB vender on the web.