Unix Toolchain Quickstart

This is a tutorial for using the Maple with a standard Unix toolchain (make, gcc, etc.). It’s not necessary to do this in order to program the Maple; you can always install the Maple IDE instead. This document is intended for users who are comfortable using C or C++ and would like to use libmaple directly.

We currently have instructions for 32- and 64-bit Linux and OS X Snow Leopard. If you’re on another Unix platform, Windows, or an earlier version of OS X, we imagine you can translate/port these directions on your own. You might want to begin with these stripped down distributions of the CodeSourcery GCC compiler tools (including Win32 versions). If you do have success on other platforms, please post in the forums, so we can fold your tips into this document!

Requirements

You’ll need a Maple board, a Mini-B USB cable, a functional computer, and root (or Administrator) access to that computer. This guide assumes you’ve had success with the IDE on your machine and that you are fairly comfortable with the Unix command line. Some previous experience with editing your shell startup script (.bashrc, .tcshrc, etc.) and using GCC and make is recommended.

Setup

Linux

These instructions are oriented towards Linux users using a contemporary Debian-based distribution.

1. Collect and Install Tools

First, you’ll need some tools:

$ sudo aptitude install build-essential git-core wget screen dfu-util \
                        openocd python python-serial

You’ll want to install a bunch of developer “basics” like make, tar, etc. A good catch-all for these tools is the build-essential meta-package on most Debian platforms: installing this fake package will pull in dozens of useful tools without bogging your system down too much.

Git is a distributed code versioning system we use to track changes in our source code; git-core is the corresponding package.

wget is a simple tool to download files over http from the command line; installing it is optional (you could pull in the required downloads using a browser).

screen is a screen manager; in the context of Maple, we use it to connect to serial port devices.

dfu-util is a tool from the OpenMoko project that we use to upload programs to the Maple over USB.

openocd is a JTAG control program used in conjunction with an ARM JTAG device to do in circuit debugging (pause/resume program execution, upload and download code, read out register status, etc). It’s also optional.

Lastly, our reset script (which sends control signals over the USB-serial connection to restart and enter the bootloader) is written in Python, and requires the PySerial library available in the python-serial package. This can also be installed with easy_install.

2. Fetch libmaple and Compiler Toolchain

$ cd ~
$ git clone git://github.com/leaflabs/libmaple.git libmaple
$ cd libmaple
$ wget http://static.leaflabs.com/pub/codesourcery/gcc-arm-none-eabi-latest-linux32.tar.gz
$ tar xvzf gcc-arm-none-eabi-latest-linux32.tar.gz
$ export PATH=$PATH:~/libmaple/arm/bin # or wherever these tools ended up

This step is fairly straightforward: do a git clone of the libmaple repository to some directory, then download and extract the ARM compiler toolchain.

The arm/bin/ directory will need to be added to PATH; you can check that this worked by entering arm-none- and hitting tab to auto-complete (your shell should show a bunch of results). Regardless of where you put the toolchain, make sure to preserve its internal directory layout, as the binaries make relative path calls and references.

After you’re done, you’ll probably want to update your shell startup script so ~/libmaple/arm/bin stays in your PATH.

3. Install udev Rules

From the libmaple directory,

$ groups # make sure it includes plugdev; if not, add yourself to it
$ sudo cp support/scripts/45-maple.rules /etc/udev/rules.d/45-maple.rules
$ sudo restart udev

As a security precaution on Linux, unknown USB devices can only be accessed by root. This udev script identifies the Maple based on its vendor and product IDs, mounts it to /dev/maple, and grants read/write permissions to the plugdev group. After restarting udev you’ll need to fully unplug or power cycle any Maples connected to the computer.

So far, so good?

Great! Test your setup by compiling a sample program.

OS X

These instructions have been tested successfully on OS X 10.6.4. As stated previously, this document assumes a general level of Unix aptitude on the part of the reader; if you’re uncomfortable using Terminal (or if you don’t know what that means), then you should probably stick with using the Maple IDE to write programs.

1. Collect and Install Tools

You will need the following tools[1] to get started:

1. XCode: If you’re reading this, you’ve probably already got this. Provides compilers and other basic tools of the trade. While XCode was once free of charge, Apple has since begun charging for it; if you’d rather not pay, you can probably get by with just a make binary.

2. Git: All of our code is tracked by a distributed versioning system called Git. A Mac installer is available.

3. dfu-util: A tool from OpenMoko that we use to upload programs to the Maple over USB. If you prefer to compile from source, OpenMoko provides instructions for building dfu-util.

If you’re in a hurry, you can steal a dfu-util binary from a program called OpenMoko Flasher. To do this, first download OpenMoko Flasher, then copy the OpenMoko application into your /Applications folder (or wherever you like). Let’s pretend you saved the .app to the directory

/Applications/OpenMoko Flasher.app

Then the dfu-util binary resides in

/Applications/OpenMoko Flasher.app/Contents/Mac OS/dfu-util

To get access to it from the command line, just make a symbolic link to the binary from some place on your PATH:

$ ln -s /Applications/OpenMoko\ Flasher.app/Contents/Mac\ OS/dfu-util \
        /somewhere/on/your/PATH/dfu-util

Note

Just copying the binary somewhere doesn’t work, as it relies on dynamically linked libraries found elsewhere in the .app bundle. It’s possible to pull just the relevant pieces out of the .app, but you’re on your own.

To make sure this worked, try plugging in your Maple, making sure it’s in perpetual bootloader mode (do this by pressing RESET, then quickly pressing BUT and holding it for several seconds), then running

$ dfu-util -l

If you see some lines that look like

Found DFU: [0x1eaf:0x0003] devnum=0, cfg=0, intf=0, alt=0, name="DFU Program RAM 0x20000C00"
Found DFU: [0x1eaf:0x0003] devnum=0, cfg=0, intf=0, alt=1, name="DFU Program FLASH 0x08005000"

then you’re all set.

4. PySerial: our reset script (which sends control signals over the USB-serial connection to restart and enter the bootloader) is written in Python and requires the PySerial library. Download the latest version. After you download and untar, install it with

$ cd /path/to/pyserial-x.y
$ python setup.py build
$ sudo python setup.py install

The package is also available via easy_install, so if you’re comfortable using that, you could also install it with

$ easy_install pyserial

2. Fetch libmaple and Compiler Toolchain

You first need to clone libmaple:

$ cd ~
$ git clone git://github.com/leaflabs/libmaple.git libmaple

Then you need to get the cross-compilers we use to build a project. These are just modified versions of GCC; you can download them for OS X here. Let’s say you saved this file to

~/Downloads/gcc-blah-blah-osx32.tar.gz

You can then unpack the archive and let OS X know where the compilers live with

$ cd ~/Downloads
$ tar -xvzf gcc-blah-blah-osx32.tar.gz
$ mv arm ~/libmaple/arm
$ export PATH=$PATH:~/libmaple/arm/bin

After that’s done, you’ll probably want to update your shell startup script so ~/libmaple/arm/bin stays in your PATH.

So far, so good?

Great! Go on to the next section, where you test everything out.

Test compilation

Get back into the libmaple directory (this tutorial assumes you put it in ~/libmaple) and test that you’ve installed all the compilation tools correctly:

$ cd ~/libmaple
$ cp main.cpp.example main.cpp
$ make clean
$ make

If it all works out, you should end up seeing something like this:

find build -iname *.o | xargs arm-none-eabi-size -t
   text    data     bss     dec     hex filename
    482       4      24     510     1fe build/wirish/comm/HardwareSerial.o
    260       0       0     260     104 build/wirish/comm/HardwareSPI.o
     60       0       0      60      3c build/wirish/wirish.o

[...]

   2196       0       1    2197     895 build/libmaple/usb/usb_lib/usb_core.o
   1904       0       0    1904     770 build/libmaple/usb/usb_lib/usb_regs.o
     56       0       0      56      38 build/libmaple/usb/usb_lib/usb_init.o
    344       0       0     344     158 build/libmaple/usb/usb_hardware.o
   6637       0      58    6695    1a27 build/main.o
  21499     201     391   22091    564b (TOTALS)

Final Size:
arm-none-eabi-size build/maple.out
   text    data     bss     dec     hex filename
  21824     200     552   22576    5830 build/maple.out
Flash build

The dec field at the end gives the total program size in bytes. The long listing of object files above the Final Size helps to identify bloated code. As you write larger projects, you may find that they use too much space. If that happens, the file-by-file listing will help you track down the culprits.

Upload a program

Let’s blow away the little example program and upload the interactive test session to your Maple. This will let you interact with the Maple over a USB serial port. If you’re on Linux, then before executing make install, you’ll want to have the udev rules setup as described above.

Plug in your Maple using the Mini-B USB cable; then run

$ cd ~/libmaple
$ cp examples/test-session.cpp main.cpp
$ make clean
$ make
$ make install

A number of things can go wrong at this stage. Simple debugging steps include using perpetual bootloader mode, restarting the Maple a couple times, make clean, etc. If nothing works, the forum is your friend.

Communicate over USB-Serial interface

Now let’s try out the interactive test session. The serial port device file should look something like /dev/ttyACMXXX on Linux or /dev/tty.usbmodemXXX on OS X, but XXX will vary depending on your system. Try using one of these to find out which it is:

# Linux
$ ls /dev/ttyACM*

# OS X
$ ls /dev/tty.usbmodem*

To open up a session, run

$ screen /dev/ttyXXX

If the interactive test program built and uploaded correctly, screen won’t report any errors, and will present you an empty terminal. Your board is now waiting for you to send it a command. Type h to print a list of commands which demonstrate various features; type any command’s letter to run it.

To exit the screen session, type C-a C-\ (control-a, followed by control-backslash) on Mac, or C-a k (control-a k) on Linux, and type y when prompted if you’re sure.

Note

Using screen sometimes messes up your terminal session on OS X. If your shell starts acting funny after you exit screen, you should be able to fix it with

$ reset && clear

If that doesn’t work, just close the Terminal window and open up a new one.

Starting your own projects

So everything worked, and you want to start your own project? Great! There are two ways to go about it.

If your project is small, all you have to do is replace ~/libmaple/main.cpp with your own code, and you’re free to use make and make install in the same way you did when you first uploaded a program.

If you have a more complicated project, with its own Makefile and multiple source files, or if you’re using an IDE that creates its own Makefile, you’ll probably want to load libmaple from an archive (a build-time library, not a DLL).

To create an archive, use the library Makefile target:

$ cd ~/libmaple
$ make library

This will produce a build-time library in the file ~/libmaple/build/libmaple.a. To use it, make sure that you link against that library, and that the libmaple sources are in your include path.

At a minimum, your include path should contain the directories ~/libmaple/libmaple and ~/libmaple/wirish/. If you want to use one of the officially supported libraries, those live under ~/libmaple/libraries/. The main include file for the Wirish library is ~/libmaple/wirish/wirish.h.

Getting Updates

We update libmaple fairly frequently with bugfixes and other improvements. In order get access to these in your local copy of the repository, you should periodically update it with:

$ cd ~/libmaple
$ git pull

We keep releases of libmaple and the Maple IDE in lockstep, so any IDE updates will have corresponding library updates. Our blog is the place to watch for major releases; an RSS feed is available.

You can sign up for a free GitHub account and watch libmaple to receive notifications about bleeding-edge development.

Debug with OpenOCD

TODO. For now see this great guide from fun-tech.se, and the jtag Makefile target. There is also a JTAG How-To page on our wiki which you may find useful.

Go forth exuberantly!

Let us know what you come up with! Use #leaflabs on Twitter, post in the forum, join the the #leafblowers IRC channel on freenode, whatever. We love projects!

Footnotes

[1]	Some of these software packages might be available on MacPorts or Homebrew. The author had some bad experiences with MacPorts a few years ago, though, and hasn’t touched a package manager on OS X since. Of course, your mileage may vary.