Stella port for the Chumby One

+bcombee · May 14, 2012

(I originally posted this on the Chumby forums at http://forum.chumby....id=42697#p42697)

Yesterday, at the Austin Mini Maker Faire, I was demoing recent developments in the homebrew Atari 2600 world. One of the things I was showing was my Chumby One turned into a Stella box, running the Atari 2600 emulator with a ROM selection menu.

I hooked the emulator into the Chumby boot process by creating a script in /psp/rfs/userhook2 that looks like

#!/bin/sh
# userhook2 - start stella if joystick is attached at boot

# if ( dmesg | grep X-Box > /dev/null) ; then
if [ -e /dev/input/js0 ]; then
echo userhook2: joystick detected >> /tmp/userhook.log
exec /mnt/storage/atari2600/stella -romdir /mnt/storage/atari2600 > /tmp/stella.log
else
echo userhook2: no joystick found >> /tmp/userhook.log
fi

This script looks for a joystick device on boot. If it sees one, it starts the emulator, otherwise it just goes ahead and boots the Chumby as normal.

I've got the stella binary in /mnt/storage/atari2600 along with a collection of ROM images. The stella binary I have is based on the latest 3.6.1 version from http://stella.sourceforge.net/. It's a basic port using a version of the SDL library built from https://github.com/x...-sdl/downloads. All builds were done with the falconwing toolchain downloaded from the Chumby site.

To install, untar the "stella-chumby.tgz" file into /mnt/storage the move /mnt/storage/atari2600/userhook2 into /psp/rfs. A copy of the SDL dynamic library will be in /mnt/storage/lib. The source I used is

This version of stella has a code change to let it better accomodate a wired USB XBox 360 controller. It's setup to let you use all the controller buttons to run the 2600 functions:

Left joystick + d-pad: left joystick
LT/LB - left difficult
RT/RB - right difficulty
X/Y - color/BW
back - select
start - reset
XBox button - return to ROM selector

I tried to also get this working on the Chumby 8 which has a faster processor and better screen, but the kernel on the C8 doesn't have joystick support compiled in by default, and I didn't have time before the event to try to compile up the needed kernel modules.

If you want to play with this, you can download the emulator binaries and my source trees at http://dl.dropbox.co...lla-chumby.tgz. I'm not including any game ROMs, but you can find a lot of hombrew ROMs in the Atari programming forums at http://www.atariage.com/