Didj

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The LeapFrog Didj

Project Summary

The Didj is a toy produced by Leapfrog marketed for educational games for 5-10 year olds. Although it 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

Project Goals

Here is a place to list all the the goals or wants that we have for this project.

  • GP2x / GP2x Wiz
    • Port Libraries
    • Flash Player
    • Emulation (Wiz Emulators)
      • NES
      • SNES
      • Gameboy BW/Color/Advanced
      • Gamegear
      • MAME
      • Atari 2600
      • Colecovision
      • Others
  • GUI
    • Custom or Modified
      • Customizable Themes
  • Homebrew Games
  • Overclock Processor

Tutorials/How To's

Technical Information

2008 version

2009 version

Discussion

Graphics Hardware

  • Resolution: 320x240
  • Display Modes: RGBA 565
  • MLC: Multi-layer controller provides HW compositing for up to three graphics layers
    • One 24-bit 2D layers (no HW accel)
    • One 16-bit 3D layer
    • One YUV video layer (no HW accel)
  • Graphics API OpenGL ES 1.1: A reduced instruction set version of OpenGL for embedded systems. OpenGL is a 3D graphics programming interface. Proprietary interface to Multi- Layer Display controller for 2D RGB and YUV video buffer support. FreeType Font renderer. Theora video codec plays OGG-Theora files.

Chip List

A picture of the front of the Didj mainboard
A picture of the back of the Didj mainboard

Processor

Memory

  • 1 QImonda HYB25DC25616OCE-5 - 32megabyte sdram Datasheet
  • 1 Micron MT29F2G08AAC - 256megabyte nand flash 8-bit Datasheet

Audio

Display Driver

Power

  • 1 Intersil ISL7665SACBAZ - Programmable Over/Under Voltage Detector Datasheet
  • 3 TI TPS62050 - Adjustable Step-Down Converter Datasheet

Crystals

  • Oscillators
    • 12MHz xtal
      • For usb
    • 27MHz xtal
      • For the Processor*
    • Barrel xtal
      • For the RTC 32.768KHz*

Test Pads

  • Possible JTAG on pads

or touch screen interface?

    • TP8 - Vcc
    • TP9
    • TP10
    • TP11
    • TP12
    • TP13
    • TP14 - Vss

Ethernet?

There is info of a CS9800 Ethernet controller used on the development board

* See the processor datasheet page 20.

Cartridges

Original Cartridge

Manufactured by Sandisk

  • s740878-1
  • 4620329
  • 0621
  • 151-10043-07-a

Custom Cartridges

Home Etched Didj Breakout Board

  • Easy to make at home (can be made with a radioshack kit and a dremel)
  • The board layout was designed in eagle.
    • The Eagle Board file Download
    • The Didj Edgecard connector library file Download
      • You can use this to make any board you want.
    • Edited Didj Cartridge library Download
      • (including outlines and keepout regions according to Awesomnesser's diagrams)
  • This cartridge locks in just like the real thing.
    • It is easy to do just superglue a small piece of FR4 in the corner and dremel a notch out. (see dimensions below)
    • You will also need a spacer on the top and bottom and those dimensions are also included.

Hack an Original Cart

  • Modify an original cart to have a uart output

Claudes Cartridge

SD and USB Serial Cart

  • Features
    • Fits (mostly) within the Didj
    • Includes an FTDI FT232RL USB-Serial adaptor for Bootloader and Serial Console
    • Includes SD card slot
    • Includes solder jumpers for custom bootloader
    • Open Eagle source files (CC Attribution, Non-Commercial, Share Alike)
  • Front and Back PDF
  • Eagle files
  • BatchPCB public design
  • Comments welcome!
    • Gerbers haven't been made yet. Please post comments here, or as a message to me.
    • I think the design is correct based on Claude's schematic and Awesomenesser's diagrams, but I can't be sure.
    • Later, I'll have this produced by BatchPCB, I'll post a link to the public design on that site, if others want boards made.

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

Important File Locations