Hardware specification 1.5

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The XO-1.5 hardware refresh

The XO-1.5 laptop was the central focus of One Laptop Per Child in 2009.

XO-1.5 is a refresh of the XO-1 laptop. As part of OLPC's continued effort to maintain a low price point, we refreshed the hardware to take advantage of the latest component technologies. This refresh (Gen 1.5) is separate from the Gen 2.0 project, and will continue using the same industrial design and batteries as Gen 1. The design goal is to provide an overall update of the system within the same ID and external appearance.

Overall, the target was to match the Gen 1 XO-1 in power consumption while making aggressive suspend easier, and in price (while changing to components which are more likely to decrease in price). These goals were met.

The Gen 1.5 machines shipped with a new software release, based on Fedora 11 and including both Sugar and GNOME, and are supported by OLPC's newer software releases.


The XO-1.5 laptops are identified by a set of three dots on both sides of the hinge cover.

XO-1.5 Hinge Cover


Dimensioned Drawing of XO, click to enlarge

The definitive XO-1.5 laptop specification is only available in PDF form ("CL1B" is the model identifier in the manufacturing data for the XO-1.75 hardware).

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

Physical dimensions

  • Approximate dimensions: 242mm × 228mm × 32mm (see drawing to the right for detailed dimensions)
  • Approximate weight:
    • XO laptop with LiFePO4 battery: 1.32KG (~3lbs);
  • Configuration: Convertible laptop with pivoting, reversible display; dirt- and moisture-resistant system enclosure; no fan.

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. All the chip data sheets should be publicly available when this laptop reaches production. At this time, they are still being written and reviewed for release.
  • 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).
  • 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
  • Embedded controller: ENE KB3700 or ENE KB3700B;
  • DRAM memory: 1 GiB dynamic RAM; data rate: DDR2 SDRAM;
  • BIOS: 1 MiB SPI-interface flash ROM;
  • Open Firmware used to load the operating system;
  • Mass storage: 4 GiB NAND flash in an internal microSD card (not user-changeable without opening the unit with a screwdriver). Also, one externally accessible SD card slot as in the original XO.
  • Drives: No rotating media.
Prototype Motherboard


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. ( DCON Datasheet )
  • 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.

Gen 1.5 will continue with the existing display, although OLPC is working with PixelQi to try to improve the brightness and efficiency of the screen.

Integrated peripherals

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;
  • Wireless Networking: Integrated 802.11b/g (2.4GHz) interface; dual adjustable, rotating antennas support diversity reception;
    • Marvell Libertas wireless chip, 88W8686, with SDIO interface, on removable module; remains powered while the laptop suspends, waking the laptop if a packet addressed to it arrives.
  • Status indicators: Power, battery, and WiFi (2), 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 18 V input usable, –32 to +40V input tolerated; power draw limited to 25 W; - see power connector dimensions at Battery and power.
  • 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.


  • Pack type: 2 cells LiFePO4, approx. 6.5V series configuration;
  • Capacity: 2800 mAh
  • Fully-enclosed “hard” case; user removable;
  • Electronics integrated with the pack provide:
    • Identification;
    • Battery charge and capacity monitoring chip (Maxim DS2756 data sheet);
    • Thermal and 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

See Laptop Batteries or more information.



  • Open Firmware (including hardware initialization and fast resume).
  • Panasonic ML1220 battery

Environmental specifications

  • Temperature: UL certification planned to 45C in Q32007, pending 50C certification in mid-2008; UNREVIEWED
  • 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; UNREVIEWED
  • Maximum altitude: –15m to 3048m (14.7 to 10.1 PSIA) (operating), –15m to 12192m (14.7 to 4.4 PSIA) (non-operating); UNREVIEWED
  • Shock 125g, 2ms, half-sine (operating) 200g, 2ms, half-sine (non-operating); UNREVIEWED
  • 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); UNREVIEWED
  • 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 will be met;
  • The laptop is intended to meet IEC 60950-1, EN 60950-1, and CSA/UL 60950-1 specifications. It will also comply with UL 1310 and UL 498. In order to guarantee the safety of children using the laptop, it passes ASTM F 963;
  • 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.

Laptop Development Schedule

Early versions of the hardware (bare board) should be available for driver development at the end of May 2009; see XO1.5 Bringup and XO 1.5 A1. A larger number of prototype laptops (several hundred) for software development and testing will become available around the end of August 2009. The OLPC contributors program will be the preferred way of requesting a Gen 1.5 machine for testing your software for compatibility or development. We hope to use the contributors program to ensure Gen 1.5 support for the wide variety of application and OS solutions created for Gen 1.0.

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.

See also