Teensy LC, 3.0, 3.1, 3.2 support

These ARM Teensies are now supported through chibios.

You’ll need to install an ARM toolchain, for instance from gcc ARM embedded website, or using your favourite package manager. After installing, you should be able to run arm-none-eabi-gcc -v in the command prompt and get sensible output. This toolchain is used instead of avr-gcc, which is only for AVR chips. Naturally you’ll also need the usual development tools (e.g. make), just as in the AVR setting.

Next, you’ll need ChibiOS. The current release (3.0.2) does not have sufficient Kinetis support, so you’ll need to get a patched version from my fork: you can download a current tree zipped from here. Unpack the zip, rename the newly created ChibiOS-kinetis to chibios, and move it to tmk/tool/chibios/ (so that the ChibiOS files reside in tmk/tool/chibios/chibios).

This should be it. Running make in keyboard/teensy_lc_onekey should create a working firmware in build/, called ch.hex.

For more notes about the ChibiOS backend in TMK, see tmk_core/protocol/chibios/README.md.

About this onekey example

It’s set up for Teensy LC. To use 3.x, you’ll need to edit the Makefile (and comment out one line in mcuconf.h). A sample makefile for Teensy 3.0 is provided as Makefile.3.0, can be used without renaming with make -f Makefile.3.0.

Credits

The USB support for Kinetis MCUs is due to RedoX. His ChibiOS fork is also on github; but it doesn’t include Teensy LC definitions.

Features that are not implemented yet

Currently only the more fancy suspend features are not there (i.e. “breathing” LED during suspend, power saving during suspend, sending a wakeup packet). The rest should work fine (reports either way are welcome).

Matrix programming notes

The notes below explain what commands can be used to examine and set the status of Teensy pins.

ChibiOS pin manipulation basics

Pins

Each pin sits on a “port”, each of which comprises at most 32 individual pins. So for instance “PTC5” from Kinetis manual/datasheet refers to port C (or GPIOA), pin 5. Most functions dealing with pins take 2 parameters which specify the pin -- the first being the port, the second being the pin number.

Within ChibiOS, there are definitions which simplify this a bit for the Teensies. TEENSY_PINn_IOPORT represents the port of the MCU’s pin connected Teensy’s PIN n, and TEENSY_PINn represents its MCU’s pin number.

Mode

A MCU pin can be in several modes. The basic command to set a pin mode is

    palSetPadMode(TEENSY_PINn_IOPORT, TEENSY_PINn, PAL_MODE_INPUT_PULLUP);

The last parameter is the mode. For keyboards, the usual ones that are used are PAL_MODE_INPUT_PULLUP (input with a pullup), PAL_MODE_INPUT_PULLDOWN (input with a pulldown), PAL_MODE_INPUT (input floating, a.k.a. Hi-Z), PAL_MODE_OUTPUT_PUSHPULL (output in the Arduino sense -- can be then set HIGH or LOW).

Setting

Pins are set HIGH (after they’ve been put into OUTPUT_PUSHPULL mode) by

    palSetPad(TEENSY_PINn_IOPORT, TEENSY_PINn);

or set LOW by

    palClearPad(TEENSY_PINn_IOPORT, TEENSY_PINn);

Reading

Reading pin status is done with

    palReadPad(TEENSY_PINn_IOPORT, TEENSY_PINn);

The function returns either PAL_HIGH (actually 1) or PAL_LOW (actually 0).