Open source hardware PDA with Linux preinstalled.
- Educational applications (e-books, CS lessons, etc)
- People need quick access to news, weather, Web, or digital books
- People need peer-to-peer voice or data connectivity, especially in infrastructure-poor places
Design Goals Edit
- Small, cheap
- Long battery life
- Peer to peer ad-hoc wireless TCP/IP networking
- Free software, open hardware
- Complete software development environment on board
- Reusable design for embedded computing (to enable TTT!)
Hardware Detail Edit
- Open hardware and software (no big SW license fees!)
- Simplified backplane bus using 1Mbps SPI for low cost
- On-board power management for long battery life (50mW while decoding MP3s)
- 128x64 pixel onboard LCD, possibly VGA or NTSC output in next version
- Projected system cost in volume O($50), easy to integrate into a cheaper few-chip solution
Built-In Networking Edit
- Standards-based (TCP/IP)
- Everything peer-to-peer:
- Wireless LAN: 900MHz, 1mW, 200Kbps peering or hub-and-spoke internet gateways
- RS-485 wired LAN: 1Mbps multidrop. Ethernet consumes too much power, Cat-5 cable is too expensive
- Easy transition between connected? or detached modes
Software Applications Edit
- Software Footprint: < 1MB!!!!
- Web browser, full TCP/IP software suite, NFS, web server, etc.
- Native or cross-compile -- either way a full software development environment: vi, emacs, C and Scheme
- MP3 audio and IP telephony support in hardware
- Browse or navigate with onboard buttons and wheel; write code with external keyboard/mouse
Hardware Reuse Edit
- Cheap embedded controller for tasks bigger than a PIC can handle
- Embedded routers, wireless gateways, data loggers, process controls, info displays, toasters, thermostats, robotic pets, ?
- Everybody owns all software IP through GNU Public License (hardware is ML licensed)
- Design is scalable through Motorola ColdFire 50MIPS solutions or Verilog 68K models
PDA System Architecture Edit
Four reusable main modulesEdit
- Processor core containing Motorola Dragonball, 8MB flash, 8MB DRAM, running Linux
- Mothercard containing audio DSP, 200Kbit/sec TDMA/FDMA data radio, backplane bus controller, and up to 64MB removable flash
- Removable user interface board
- Docking station containing battery charger, serial port, keyboard port, RS-485 multidrop network
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