Main -> Hardware Overview

  1. Hardware Overview
    1. Specifications and Features
    2. Connectors & Ports
  2. Components Overview
    1. OSWALD CORE
    2. Interface System
  3. Schematic
    1. CORE.0
    2. CORE.1
    3. INTERFACE.0 & INTERFACE.1
  4. Miscellaneous Information
    1. Power Switch
    2. Boot Order Selection

Hardware Overview

The hardware for the CSPFL is designed to allow developers freedom in choosing how users interact with their applications. It was developed specifically with education in mind. The device is so flexible that every aspect of computer science can be explored using any number of approaches. One developer may be interested in applications for portable devices while another can explore desktop style applications or even drivers and microcontrollers.


Specifications and Features

  • Texas Instruments OMAP3530 applications processor
  • 128 Mbyte DDR-SDRAM (266 MHz)
  • 256 Mbyte NAND flash memory
  • 3.5" QVGA (320:240) 24bit Color LCD
  • Resistive touchscreen
  • DVI out at HD resolution (1024:768)
  • Texas Instruments TLV320AIC33 stereo audio codec
    • 24bit resolution
    • 96 kHz sampling rate
    • 3D/Bass/Treble/EQ/De-emphasis Effects
  • IEEE 802.15.4 wireless with IP over 802.15.4 support
  • Touchpad
  • 3 axis accelerometer
  • 5-way rocker switch (up, down, left, right, and center)
  • 6 general purpose buttons
  • A Speaker
  • Microphone
  • Built-in 1300mAh Polymer Li-ion battery

Connectors & Ports

Main article:Connectors

  • 3.5mm stereo headphone port
  • HDMI (not fully complaint, just as a small DVI port)
  • Secure Digital card slot
  • 2 USB full speed host ports (USB-A)
  • Power jack

Components Overview


OSWALD CORE

The first prototyped CORE system

1 Texas Instruments OMAP3530 applications processor
2 256 Mbyte NAND flash memory
3 128 Mbyte DDR-SDRAM (266 MHz)
4 Secure Digital card slot Unfortunately card not included
5 Texas Instruments TFP410 DVI Transmitter
6 DVI-D single link output In the form of an HDMI connector for size
7 TFT-LCD connector
8 Texas Instruments TLV320AIC33 stereo audio codec
9 3.5mm stereo audio jack
10, 11 Texas Instruments TUSB1106 USB Transciever
12 Texas Instruments TUSB2046B 4 port full speed USB hub
13, 14 USB Type A host receptacle
15 USB Mini-B device receptacle Currently can only be used to charge, future releases will actually support USB device
16 Texas Instruments BQ24032A battery charge manager
17 DC power input Fits 2.1mm ID, 5.5mm OD connectors
18 System power switch
19 Texas Instruments TPS65023 system power management Provides power for the OMAP, NAND, and DDR-SDRAM
20 Texas Instruments BQ27500-V100 battery fuel gauge
21 Polymer Li-ion battery
22 Real-time clock with alarm
23, 24 Expansion connector
25 Boot order select button

A few parts are occluded by the battery. They include the main 3.3V power supply, the 5V power supply and the LCD back light supply.

Interface System

Interface Board

1 Texas Instruments cc2431 wireless system
2 Atmel ATmega48 microcontroller reads the accelerometer and sends data to the CY8C24794
3 Board to board connector This connects to the back of the core board so it can talk to the system
4 Freescale MMA7340L Accelerometer
5 4 wire touchscreen connector
6 Texas Instruments TSC2046 4 Wire resistive touchscreen controller
7 Cypress CY8C24794 PSoC Device
8 Cypress programming interface
9 ATmega48 programming interface
10 CC2431 programming interface

Schematic

The full schematics can be found in the source tree. The schematics are provided as PDFs, PADS Logic binary, and PADS Logic 2005 ASCII. If there is any ambiguity or inadequate documentation, please make a ticket detailing the problem so we can improve it.

CORE.0

Schematics can be found at source:trunk/hardware/OSWALD_CORE.0/Schematic

CORE.1

Schematics can be found at source:trunk/hardware/OSWALD_CORE.1/Schematic

INTERFACE.0 & INTERFACE.1

Schematics can be found here source:trunk/hardware/OSWALD_INTERFACE/Schematic

Miscellaneous Information


Power Switch

The power switch provides the usual functions (system power on and off) but with a few differences. When switched on, the system power immediately switches on (as one might expect). Once the system is powered and the switch is moved to the "off" position, it flags the OMAP processor with an interrupt to request Linux to shutdown (or whatever you would like it to do) and about 10 seconds later actually cuts power from the system. This was implemented so that systems lacking any software to power-down the device - or is frozen - can be turned completely off.

Also implemented as part of the power switch (the circuitry just below the switch in the pictured above) is a lockout feature that prevents the system from starting if the battery is severely low on power (battery voltage of 2.7V or less). The lockout will disengage once the battery has been charged sufficiently (battery voltage 3.2V or more).

Boot Order Selection

The OMAP processor follows a predefined list of devices to check for the boot loader software (called X-Loader). It starts by checking the first few bytes in the NAND flash to determine if a valid boot loader exists there. If it does not (i.e. the NAND has been erased) then it will move on to checking the MMC/SD card (if one is inserted). This process is analogous to selecting boot order in a normal computer's BIOS (e.g setting the PC to boot from the hard drive first then the CD-ROM).

There are (and will be) times when the first few bytes of the NAND contain the correct information for the OMAP to think that there is a valid boot program but the program is actually broken. This can happen when trying new boot programs that don't work or for some reason the NAND become partally erased. When this happens the OMAP will begin running the broken program and never make it to the MMC/SD card thus turning your system into a brick. Fortunately there is a small button (#25 above) that when pressed, will reverse the device boot order (i.e. it will start at the MMC/SD then try the NAND). This allows a simple method to recover the system by using a normal flasher SD.

Attachments