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 It has been replaced by the Leapster Explorer.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