KLtab - Kinetis L series Throw-Away Board

Werner Almesberger werner at almesberger.net
Tue Sep 30 05:09:01 UTC 2014

To experiment with the permission bits of the KL2x MCUs, I designed a
very simple and very cheap board. Since it's quite likely that some of
these experiments will end with locking up the chip for good, it's
important that these boards be as un-fancy as possible.

Here are the schematics:

And the layout:

The board is single-sided, but I had to cheat a little and cross
conflicting traces with two 0 Ohm resistors (R5 and R8).

The only things that are required are the MCU, all the capacitors but
C1, and a connection to some programmer on CON5. The following features
are optional:

- two LEDs going to GND (to they're lit when the CPU drives them high),
  connected to high-drive pads,
- two LEDs going to 3.3 V (to they're lit when the CPU drives them
  low), also connected to high-drive pads,
- a Micro USB AB (or B) connector with series resistors, to play with
  USB if SWD gets too boring.

Note that there's no crystal, so USB will have to content itself with
the internal RC oscillator. This should be good enough for device mode,
but may not quite cut it for host mode.

- Werner

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