This Makefile compiles C/C++ code for a Teensy-LC USB development board without the Arduino IDE.

Setup

The simplest way to get the latest Teensy compiler and core libraries is to install Arduino IDE and the Teensyduino plugin. You will not be using the IDE, just the plugin.

Next, fix the three symlinks in ./Compiler. They should point to:

1. arm-bin -> /path/to/your/arduino-ide/hardware/tools/arm/bin/
2. teensy3 -> /path/to/your/arduino-ide/hardware/teensy/avr/cores/teensy3
3. teensy-tools -> /path/to/your/arduino-ide/hardware/tools

Usage

To compile program.hex:

make

Note: the first time this is run, it also compiles all the core teensy sources into teensy3.a

Or, to compile and automatically launch the Teensy Loader:

make load

To clean all compiled files:

make clean

Background

Finding the magical combination of programs and flags to create a working hex file was a very frustrating process. The Makefile provided by PJRC (arduino/hardware/teensy/avr/cores/teensy3/Makefile) did not work for me because the linkage step silently ignored any undefined references. The linker worked as it should when compiling from Arduino IDE. So I set build.verbose=true in ~/.arduino15/preferences.txt and was able to observe the exact compiling commands and create this Makefile.