From: eLinux.org

Didj

This device is part of the LeapFrog Pollux
Platform, it’s
recommended to start there for general information.

The LeapFrog Didj

Contents

• 1 Summary
• 2 Platform
• 3 Boot Loader
• 4 Sources and Toolchains
• 5 Tutorials/How To’s
• 6 Development Scripts and
  Programs
• 7 Technical Information
• 8 Images
• 9 External Links

Summary

The Didj was a toy produced by Leapfrog marketed for educational games
for children aged 5-10.

Didj was end-of-lifed by Leapfrog in mid-2010. It has been replaced by
the Leapster Explorer.

Although Didj has a proprietary graphical front end, it runs a generic
Linux distribution on an Arm based processor. Soon after the Didj’s
release, it was discovered that the cartridge port contained pins that
allowed for serial console access with root privileges. After this
discovery, work began to modify the Didj into an accessible emulation
device.

Since development began, much has been accomplished, including:

• Discovered that the Arm chip is the same as on the GP2X
  Wiz, only at a lower clock speed.
• Created cartridges that support SD cards
• Accessed the UART features in the cartridge slot

Platform

LeapFrog Pollux
Platform

The Didj is part of 3 different devices that all share a common hardware
platform, based around the Pollux SoC. The platform
page contains information generic across these devices, and it is
recommended that you refer to that page as it is a good starting point
to understanding the Didj, and contains some basic How To’s and
Tutorials to get you started.

Boot Loader

• Lightning Boot
• U-Boot
• Compile and Install
  Emerald-Boot

Sources and Toolchains

• Sources and
  Toolchains

Tutorials/How To’s

General

• Common Commands
  Reference
• Console
  Access
• Cartridges
  • Cartridge
    Settings
• Extract lfp/lf2
  Archives

Networking

• Enable Networking via USB
  Gadget
• Install Dropbear
  SSH
• Playing MP3 network streams and
  files
• Networking
  Setup
• Networking
  Applications
• Internet Access from
  Device
• Mount NFS
  Directory

USB Storage

• USB Mounting Under Windows, Linux, and OS
  X
• SCSI Commands

Cartridge

• Make an ATAP NAND Cartridge

Flash NAND

• Flash Data to
  NAND
• Updating
  Bootloader/Firmware

Firmware Image

• Mount JFFS2 Image on
  Linux

  • Relevant Settings
  • Correct endianess

• Create JFFS2
  image

  • Relevant Settings
  • -e 128
  • -p

Kernel/RootFS/Firmware

• Building
  libSDL
• Building SDL_ttf font
  library
• Building SDL_image library with jpg and png
  support
• Building SDL_mixer audio
  library
• Building
  tslib
• SDL
  Resources
• Didj Kernel 2.6.31
  Upgrade
• 2.6.31 Kernel for
  Didj
• Boot Kernel and Rootfs from SD
  w/Framebuffer
• Linux Framebuffer
  Driver
• Enable SD Card
  Module
• Building The Explorer Root File
  System
• Changing the fb driver to display the boot logo
  correctly
• TV
  Out
• Generic Buildroot Rootfs and Kernel
  build

Games and Emulators

• Emulators and
  Games

Brio Development

• Replacing the default App Menu from the default App
  Menu

JTAG

• JTAG
  Pinouts
• Pollux FTDI JTAG How
  To
• Pollux JTAG Wiggler
  Config
• JTAG Kernel
  Boot

Compiling Source Code

• Set up the Build
  Environment
• Kernel
  Configuration

Development Scripts and Programs

• LF1000 UART Bootstrap
  Utility
  written in Python
• LF1000 UART Bootstrap
  Utilities
  based on the OMAP boot utilities from TI

Technical Information

• Initial Memory Map Dump
• Map of Didj GPIO Pins
• Device
  Comparison

File System Info

• rootfs / rootfs rw
• /dev/root / jffs2 ro
• none /proc proc rw
• sysfs /sys sysfs rw
• /dev/ram0 /tmp tmpfs rw
• /dev/mtdblock1 /flags jffs2 rw,sync,noatime
• /dev/mtdblock2 /mfgdata jffs2 ro,sync,noatime
• /dev/mtdblock10 /Didj vfat
  rw,noatime,fmask=0022,dmask=0022,codepage=cp437,iocha rset=iso8859-1
• /dev/mtdblock11 /Cart vfat
  ro,noatime,fmask=0022,dmask=0022,codepage=cp437,iocha rset=iso8859-1

Filesystem                Size       Mounted on
/dev/mtdblock6           14.0M     /
/dev/mtdblock1          896.0k    /flags
/dev/mtdblock2            1.0M    /mfgdata
/dev/mtdblock9          215.8M    /Didj

Active Kernel/Rootfs

Near the begging of the boot message you should see one of two root
options:

root=31:04

You are using mtd4: 00e00000 00020000 “Linux_RFS0” or

root=31:06

You are using mtd6: 00e00000 00020000 “Linux_RFS1”

Partitions

Battery Compartments

The Didj has two identical battery compartments, the combined collection
of batteries are wired in series.

• Battery Compartment Terminals:
  • Term 1 - Battery +
  • Term 2 - Temp Sensor + Wired to Pollux pins K20 / GPIOA 28 and
    K21 / GPIOA 29
  • Term 3 - Temp Sensor -
  • Term 4 - Battery -

Rechargeable Batteries

In addition to the terminals facing the Didj’s contacts, there are
another set of contacts facing away from the Didj. These contacts are
duplicates used by the charging station. The batteries themselves are
NIMH cells, producing around 2.5v per pack when fully charged.

Recharging Station

The recharger station contains a battery charge circuit with temperature
monitoring. The station also has a pair of contacts that duplicate the
9V dc barrel jack.

SSP / SPI Controller Didj SPI
Info

Images

• PCB Images

• Error creating thumbnail: Invalid thumbnail parameters

  Front side mainboard, with LF1000 CPU and SDRAM de-soldered.

• 

  Close up of the LF1000 CPU ball-grid.

• Error creating thumbnail: Invalid thumbnail parameters

  Back side mainboard, with cartridge socket and NAND de-soldered.

• 

  Front side mainboard

• 

  Back side mainboard

External Links

• Cozybit boasts of their involvment in integrating Linux with the
  Didj
• Hacking around with the Leapfrog
  Didj
• Claude’s Didj Hacking
  Page
• Hackaday Posts
  • Didj
    Hacking
  • Didj Hacking
    Followup

Categories:

• Didj
• LeapFrog Pollux
  Platform