Hardware specification 1.5

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The XO-1.5 laptop is a refresh of the XO-1 laptop. In our continued effort to maintain a low price point, OLPC refreshed the hardware in 2009 to take advantage of the latest component technologies. This refresh (Gen 1.5) is separate from other projects (XO-2, XO-3), and will continue using the same industrial design and batteries as XO-1. The design goal is to provide an overall update of the system within the same industrial design and external appearance.

Overall, the target was to match the Gen 1 XO-1 in power consumption and price, while improving components, making aggressive suspend easier and improving touchpad response. XO-1.5 machines shipped with a new software release, based on Fedora 11 and including both Sugar and GNOME software. Newer software releases for this laptop are now available.

Specifications

XO-1.5 Identifier

Dimensioned Drawing of XO, click to enlarge

The definitive XO-1.5 laptop specification is available at CL1B hardware specification ("CL1B" is the model identifier in the manufacturing data for the XO-1.5 hardware).

The specs below are not authoritative, please refer to the PDF version of the spec linked above.

Physical dimensions

Approximate dimensions: 245mm × 230mm × 30.5mm (see drawing to the right for detailed dimensions)
Approximate weight with LiFePO4 battery: 1.45KG (~3.20lbs);
Configuration: Convertible laptop with pivoting, reversible display; dirt and moisture-resistant system enclosure; no fan.
An XO-1.5 is externally differentiated from the XO-1 by three raised dots on the hinge cover.

Core electronics

A photo of the XO 1.5 Motherboard is available with annotations.
CPU: Via C7-M Ultra Low Voltage x86-compatible processor with 128KB L2 cache;
- No datasheet is publicly available.
CPU clock speed: 400 MHz (1.5 W) to 1GHz (5 W), variable. The clock may be throttled back automatically if necessary to meet thermal constraints; Clock speed changes happen very quickly, as does dropping the processor voltage (0.728V in C3/C4, as compared to 0.798V in C0).

The C0 voltage continued to drop through production, to be as low as 0.728V.

An Intel-compatible instruction set (including MMX, SSE, SSE2 & SSE3)
Companion chips: Via VX855 provides memory interface, a 3D graphics engine, an HD video decoder, USB, SDIO, and other system interface and management functions
- No datasheet is publicly available, but the VX855 is a minor incremental step from the 800/820. Here is the public manual for the VX800/820, and for the included Chrome9 core 2D graphics and 3D and video.
Embedded controller: ENE KB3700 or ENE KB3700B;
DRAM memory: 512 MB or 1 GiB DDR2 dynamic RAM;
Mass storage: 2 to 8 GiB NAND flash in an internal microSD card
- Not user-changeable without opening the unit with a screwdriver;
- One externally accessible full-size SD card slot.
- No rotating media.

XO-1.5 Motherboard

Display

Main article: Display

Liquid-crystal display: 7.5” dual-mode TFT display;
Viewing area: 152.4 mm × 114.3 mm;
Two "modes" depending on lighting conditions:

(1) Grayscale (B&W) reflective mode: for outdoor use—sunlight-readable; primarily lit from the front by ambient light; high-resolution (200 DPI), 1200(H) × 900(V) grayscale pixels; power consumption 0.1–0.2Watts;

(2) Color, backlight mode: for indoor use; primarily lit from behind by the LED backlight; built in sub-pixel sampling of the displayed color information results in a perceived resolution of approximately 984(H) × 738(V); power consumption 0.2–1.0Watts;

The display-controller chip (DCON) with memory that enables the display to remain live with the processor suspended. The DCON also formats data for the display.
This Liquid-crystal display is the basis of our extremely low power architecture. The XO is usable while the CPU and much of the motherboard is regularly turned off (and on) so quickly that it's imperceptible to the user. Huge power savings can perhaps be harvested in this way (e.g. by turning stuff on the motherboard off when it's not being used (if even for a few seconds), while keeping the display on).

Note: web browser images are currently scaled up so that an image of very roughly [800 × 600] fills up the browser window.

Integrated peripherals

Keyboard: 80+ keys, 1.0mm stroke; sealed rubber-membrane key-switch assembly;
- Keyboard Layouts
- Layout pictures: English, Arabic, Thai, West African (Nigeria), Portuguese, Spanish, Amharic, French, Urdu, Cyrillic, Turkish (not final), Nepali, Mongolian, Kazakh, Devanagari, Uzbek, Pashto, Dari, Pulaar (Fula), Italian
- The XO-1.5 HS ("High School") edition, identified as model CL1C in manufacturing data, has a non-membrane "clicky" keyboard.
Gamepad: Two sets of four-direction cursor-control keys;
Touchpad: Capacitance touchpad
Audio: HD Audio compatible audio subsystem; Internal stereo speakers and amplifier; internal monophonic microphone; jacks for stereo external headphones and microphones (schematic);
- Conexant CX20582 codec

Keyboard detail

Camera: integrated color video camera; 640 x 480 resolution at 30 FPS; independent (and undefeatable by software) display of microphone and camera recording status; the camera and device driver support disabling AGC and automatic color balancing, to enable its use as a photometric sensor for educational applications;
- Omnivision OV7670
Wireless Networking: Integrated 802.11b/g (2.4GHz) interface; dual adjustable, rotating antennas support diversity reception;
- Marvell 88w8686 WLAN module, with SDIO interface, on a removable module; remains powered while the laptop suspends, waking the laptop if a packet addressed to it arrives. Ad-hoc networking and 802.11s mesh support is available.

Status indicators: Power, battery, Wi-Fi, one software controlled (intended for onboard flash access), visible with lid open or closed; Microphone In-Use, and Camera In-Use, visible when lid is open.

External connectors

DC power: 6mm (1.65mm center pin) connector; 11 to 24 V input usable, –32 to +40V input tolerated; power draw limited to 25 W; - see power connector dimensions at Battery and power.
- Maximum Power Point Tracking alters voltage/current for maximum battery-charging power from solar panels
- Do not use an XO-1 power supply (which can fail if more than 17W is pulled from it); unfortunately the connector is the same.
Headphone output: standard 3.5mm 3-pin switched stereo audio jack;
Microphone input: standard 3.5mm 3-pin switched stereo microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled);
USB: Three Type-A USB 2.0 connectors; Up to 1A power supplied (total);
Flash Expansion: SD Card slot.

Connectors

Battery

Pack type: 2 cell LiFePO4; approx. 6V series configuration (subject to change);
Capacity: 22 Watt-hours;
Fully-enclosed “hard” case; user removable;
Electronics integrated with the pack provide:
- Identification;
- Battery charge and capacity monitoring chip (Maxim DS2756 data sheet);
- Thermal ad over-current sensors along with cutoff switch to protect battery;
Minimum 2,000 charge/discharge cycles (to 50% capacity of new).
Power Management will be critical
The Real-Time clock uses a separate Panasonic ML1220 rechargeable battery.

See Laptop Batteries or more information.

BIOS/loader

Open Firmware provides diagnostics, hardware initialization, and loading of the OS;
Stored in a separate 1 MiB SPI-interface flash ROM;

Environmental specifications

Temperature: 0 to 50 degrees Celsius (operating); -20 to 60 degrees Celsius (non-operating)
Humidity: UL certification planned to IP42 (perhaps higher) when closed, the unit should seal well enough that children walking to and from school need not fear rainstorms and dust;
Maximum altitude: –15m to 3048m (14.7 to 10.1 PSIA) (operating), –15m to 12192m (14.7 to 4.4 PSIA) (non-operating);
Shock 125g, 2ms, half-sine (operating) 200g, 2ms, half-sine (non-operating);
Random vibration: 0.75g zero-to-peak, 10Hz to 500Hz, 0.25 oct/min sweep rate (operating); 1.5g zero-to-peak, 10Hz to 500Hz, 0.5 oct/min sweep rate (nonoperating);
2-3mm plastic walls (1.3mm is typical for most systems).

Regulatory requirements

The usual US and EU EMI/EMC (electromagnetic-interference and electromagnetic-compatibility) requirements;
The laptop meets IEC 60950-1, EN 60950-1, and CSA/UL 60950-1 (safety) specifications. It also complies with UL 1310 and UL 498. In order to guarantee the safety of children using the laptop, it passes ASTM F 963 (Standard Consumer Safety Specification on Toy Safety, 2003 edition);
The external power adapter complies with IEC, EN, and CSA/UL 60950-1;
The removable battery pack complies with IEC, EN, and CSA/UL 60950-1 and UL 2054;
RoHS (Restriction of Hazardous Substances Directive – EU) compliant.

Serial Adapter

In order to conserve parts/space, while the motherboard does provide a serial port for debugging, it does not provide voltage translators to fully implement the RS-232 protocol. Thus a 3.3V TTL to RS-232 (or USB) Adapter is needed. The necessary adapter is a slight variant of the one used in the XO-1.

Hardware specification 1.5

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