Hardware specification: Difference between revisions

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<div style="background:gray; color:white;"><b>One Laptop per Child</b></div>
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=Hardware details for OLPC, May 28, 2006=
Maintained from a document written by Michael Bove by Jim Gettys.


The '''XO-1''' laptop is a central focus of One Laptop Per Child. After three years of development, it entered mass production in November 2007. There are now [[Deployments|millions of units deployed in the field]], and thousands more with developers and for testing in schools all over the world.
== Hardware Design Process ==
OLPC has developed newer hardware generations [[XO-1.5]] and [[XO-1.75]] that share the XO-1's industrial design.


== Specifications ==
Designing hardware is much more constrained than software; while you may sometimes have great influence on the design of a chip many months in advance of availablility, you can only actually use chips which you can get in the volumes required at prices that you can afford. Even a single missing component, or component not available in the quantities you need, may cripple your production. Many in the software community, who are used to more fluid ability to modify design and produce in unlimited copies, find this a foreign concept.
[[Image:drawing75c1.jpg|thumb|right]]
[[Image:Olpc XO dim-Optimized.png|thumb|Dimensioned Drawing of XO, click to enlarge]]


The [[Media:CL1A_Hdwe_Design_Spec.pdf|definitive laptop specification]] is only available in PDF format. This page attempts to accurately reflect that information.
Designing hardware is similar to making sausage: you may be able to grow new ingredients starting long in advance if you are friendly with farmers (chip designers). You can only make your sausage, however, with the ingredients required by your recipe that you can ''actually'' buy in the volume you need to manufacture. Sometimes you can substitute ingredients without spoiling the general recipe, and sometimes the result would be inedible. In this case, we have a single chip that Mark Foster is specifying, that sits between the CPU and the display, and over which we have detailed control.
''Note: this is the specification of the CL1A XO-1 production laptop. The specification for the earlier CL1 version (with the wide dual-mode touchpad) is [[Media:CL1_Hdwe_Design_Spec.pdf|here]].''


===Physical dimensions===
If you'd like some insight into this process, you can look at older versions of this page in the wiki.
* Approximate dimensions: 242mm × 228mm × 32mm (see drawing to the right for detailed dimensions)
* Approximate weight:
** XO laptop with LiFePO4 battery: 1.45KG (~3.20lbs);
** XO laptop with NiMH battery: 1.58KG (~3.48lbs);
* Configuration: Convertible laptop with pivoting, reversible display; dirt- and moisture-resistant system enclosure; no fan.


===Core electronics===
== High-Volume Design and Manufacturing==
* A photo of the [[XO Motherboard|XO-1 motherboard]] is available, with or without annotations.
* CPU: x86-compatible processor with 64KB each L1 I and D cache; at least 128KB L2 cache;
** [http://www.amd.com/files/connectivitysolutions/geode/geode_lx/33234G_LX_databook.pdf Datasheet] (dead link)
* CPU clock speed: 433 Mhz;
* i586 instruction set (including MMX and 3DNow! Enhanced) with additional Geode-specific instructions
* Companion chips: PCI and memory interface integrated with CPU;
** North Bridge: PCI and Memory Interface integrated with Geode CPU ([https://web.archive.org/web/20061019093748/http://www.amd.com/files/connectivitysolutions/geode/geode_lx/33234d_lx_ds.pdf info])
** South Bridge: [https://web.archive.org/web/20130626041210/http://support.amd.com/us/Embedded_TechDocs/33238G_cs5536_db.pdff datasheet]
* Graphics controller: Integrated with CPU; unified memory architecture;
* Embedded controller: ENE KB3700 or ENE KB3700B;
** [[Ec_specification|Embedded Controller]]: [[Media:KB3700-ds-01.pdf|ENE KB3700]]
* DRAM memory: 256 MiB dynamic RAM; data rate: dual-DDR333-166Mhz;
* BIOS: 1024KiB SPI-interface flash ROM;
* Open Firmware used to load the operating system;
* Mass storage: 1024 MiB SLC NAND flash; (a few "Red XOs" have been built with 2048 MiB of flash)
* Drives: No rotating media.
* CAFE ASIC (camera- and flash-enabler chip provides high-performance camera, NAND FLASH and SD interfaces); Marvell 88ALP01: [http://www.marvell.com/products/pcconn/88ALP01.jsp CAFE Specification] or [http://wiki.laptop.org/images/5/5c/88ALP01_Datasheet_July_2007.pdf local copy] plus [http://dev.laptop.org/ticket/1339#comment:17 presence detect erratum]


[[Image:Proto-a-front.jpg|thumb|Prototype-A Motherboard]]
Furthermore, production of high-volume hardware is now a very specialized business, and is now often joint between the organization/company that specifies what the hardware should do&mdash;often to the point of selection of major and minor components&mdash;and an ODM (original device manufacturer), which specializes in very high-volume design and production. The ODM generally does the detailed design for production; e.g., exact part selection if there are variants, schematics, layout, board routing, mechanical design, testing, debugging for production, logistics, and production of the finished goods.
{{anchor|Display}}


===Display===
In OLPC's case, the ODM is [http://www.quantatw.com/e_default.asp Quanta], as announced in mid December. There is a good chance that your laptop was manufactured by Quanta, headed by Barry Lam, which is possibly the largest company few people have heard of. Quanta manufactures more laptops than any other company in the world (almost 1/3rd of the total made), whether branded HP or Apple or others. Detailed design of the first production OLPC design is just starting, though OLPC has investigated (and continues to investigate) the possible components and other design tradeoffs.
{{main|Display}}
* [[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 at least 1024(H) × 768(V); power consumption 0.2–1.0Watts;
* The [[DCON|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 [[Display | 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 are 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.''
Note that CPU chip manufacturers generally provide sample designs, development boards, and application notes, that are often complete and usable by themselves, though often include interfaces or hardware you might not choose in volume production. These clarify how their products might be "designed in" to actual products. Our prototype machine seen at Tunis was using one of the AMD "Rumba" boards. It approximated much of the first OLPC hardware, though used a conventional disk rather than NAND flash, and has components we will not use (e.g. ethernet), and that conceptual (but working) model lacked the much cheaper flat panel that is under development.


[[Image:EToys - new display.jpg|thumb|right|[[Etoys]] running on the first OLPC display prototype]]
Detailed schematics and layouts of such sample AMD designs are generally available in the chip manufacturer's [http://www.amd.com/us-en/ConnectivitySolutions/ProductInformation/0,,50_2330_9863,00.html developer programs]. If you are interested in exact design details of hardware you can get for immediate experimentation, we direct your attention to these programs, which generally include the ability to buy such sample hardware. Most of the information required to program devices, however, is completely freely available at the manufacturer's web sites in fully public specifications.


===Integrated peripherals===
In concert with ODMs, such sample designs are generally customized to fit the exact product needs and engineered for high-volume-production tooling and techniques that are not applicable to low-volume development-board runs. OLPC has just entered in partnership with Quanta on this engineering-for-production phase of the project .
* Keyboard: 80+ keys, 1.0mm stroke; sealed rubber-membrane key-switch assembly;
** [[OLPC_Keyboard_layouts|Keyboard Layouts]]
** Layout pictures: [[:Image:Keyboard english.png|English]], [[:Image:Keyboard arabic.png|Arabic]], [[:Image:Keyboard thai.png|Thai]], [[:Image:NG-MP-alt.png|West African (Nigeria)]], [[:Image:BR-MP-v1.png|Portuguese]], [[:Image:ES-MP-v1.png|Spanish]], [[:Image:Ethiopic-B3.png|Amharic]], [[:Image:Rwanda-B3.png|French]], [[:Image:Urdu-MP.png|Urdu]], [[:Image:RU-MP-v1.png|Cyrillic]], [[:Image:TR-MP-v1.png|Turkish (not final)]], [[:Image:NP-MP-v1.png|Nepali]], [[:Image:MO-MP-v1.png|Mongolian]], [[:Image:KA-MP-v1.png|Kazakh]], [[:Image:MR-MP-v2.png|Devanagari]], [[:Image:UZ-MP.png|Uzbek]], [[:Image:PS-MP.png|Pashto]], [[:Image:AF-MP.png|Dari]], [[:Image:FF-MP.png|Pulaar (Fula)]], [[:Image:IT-MP.png|Italian]]
* Gamepad: Two sets of four-direction cursor-control keys;
* Touchpad: Capacitance touchpad
** ALPS Electric [[Touch Pad/Tablet|Dual capacitance/resistive touchpad]];
* Audio: AC’97 compatible audio subsystem; Internal stereo speakers and amplifier; internal monophonic microphone; jacks for external headphones or microphone;
** [http://www.analog.com/en/prod/0%2C2877%2CAD1888%2C00.html Analog Devices AD1888] and [http://www.analog.com/en/audiovideo-products/audio-amplifiers/ssm2302/products/product.html Analog Devices SSM2302] for audio amplification
[[Image:AP1 15.jpg|thumb|100px|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;
** [http://www.ovt.com/products/detail.php?id=73 Omnivision OV7670]
* [[Wireless| Wireless Networking]]: Integrated 802.11b/g (2.4GHz) interface; 802.11s (Mesh) networking supported; dual adjustable, rotating antennas support diversity reception; capable of mesh operation when CPU is powered down;
** Marvell [[Libertas]] wireless chipset, [[88W8388]] controller and [[88W8015]] radio
* 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===
Detailed schematics and board layouts of these high-volume designs are often considered proprietary to the ODM's, or jointly owned by both parties involved. They represent the competitive advantage one ODM may have with its rivals (who may have access to the same components as they do). Those design schematics are sometimes available to programmers after production starts under NDA agreements; for example, schematics of many of the iPAQ handhelds were made available to programmers in the open-source community under NDA, when insufficient written programming information was available. OLPC will try to document our designs sufficiently to avoid NDAs; we expect this will be less effort than the logistics of requiring NDAs in such a large and diverse community.
* DC power: 6mm (1.65mm center pin) connector; 11 to 18 V input usable, –32 to +40V input tolerated; power draw limited to 17 W; - see power connector dimensions at [[Battery and power#Mechanical|Battery and power]].
* Headphone output: standard 3.5mm 3-pin switched stereo audio jack;
* Microphone input: standard 3.5mm 2-pin switched mono 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.


[[Image:Rotate-1.jpg|thumb|Connectors]]
== Forseeable Designs ==


===Battery===
Currently we can forsee three generations of machines: a first one to ship in early 2007, a second production run sometime in 2007 that will incorporate a newer AMD chip and possibly a newer wireless chip, and an E-Ink (or other low-power, bistable display technology) based machine to ship when this new display technology is available at an appropriate price point. The further out, the fuzzier the crystal ball.
* Pack type: 2 or 4 cells LiFePO4; or 5 cells NiMH, approx. 6V series configuration (subject to change);
* Capacity: 16.5 Watt-hours (NIMH), 22 Watt-hours (LiFeP);
* Fully-enclosed “hard” case; user removable;
* Electronics integrated with the pack provide:
** Identification;
** Battery charge and capacity monitoring chip ([[Media:DS2756.pdf|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.
Subsequent OLPC designs may use components that have not yet been shipped by their manufacturer, and we often will arrange a program whereby the open source community can get early access to specifications of those components for driver development.


[[Image:Bottomdrawing.jpg|thumb|Battery]]
We will try to keep this specification up to date as more and more details of the first design (and subsequent designs) are nailed down, provide links to specifications for the chosen components, and provide information required to program them (e.g. address space assignments).


===BIOS/loader===
The first generation design uses already available components, with the (major) exception of the new flat panel and the chip that drives it. The electrical interface to the flat panel and the LCD panel itself is now in detailed engineering. A family of flat panels all based on a common LCD panel, but differing on their use of color filters, what kinds of backlights or temporal color, which have different properties (power consumption, resolution, gamut) and risks are being built this summer, and the initial display panel will be chosen from among these designs in September.
* [[Open Firmware]] (including hardware initialization and fast resume).
* Panasonic ML1220 battery


===Environmental specifications===
Several of these designs are very low risk and do not require innovations in manufacturing, so our initial ship schedule of the OLPC system is now much more certain than in the past. Several other designs are higher risk, but better performance, either on effective resolution or power consumption. It is quite possible we may initially use a low risk panel and phase in one of the alternatives to manufacturing later in 2007. ChiLin of Taiwan will be the manufacturer of the OLPC display. 3M is building specialized plastic optical components being used in the design of these displays.
* Temperature: UL certification planned to 45C in Q32007, pending 50C certification in mid-2008;
* Humidity: UL certification planned to [[IP_Code|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===
== First Generation System ==
[[File:RoHS_Restriction_of_Hazardous_Substances_Directive_Logo.png|right|220px]]
* The usual US and EU EMI/EMC (electromagnetic-interference and electromagnetic-compatibility) requirements will be met;
* The laptop meets IEC 60950-1, EN 60950-1, and CSA/UL 60950-1 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;
* 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;
* [http://ec.europa.eu/environment/waste/rohs_eee/legis_en.htm RoHS (Restriction of Hazardous Substances Directive – EU) compliant.]


==Laptop Development Schedule==
''Physical dimensions:''
* Dimensions: 193mm × 229mm × 64mm (as of 3/27/06—subject to change)
* Weight: Less than 1.5 KG (target only—subject to change)
* Configuration: Convertible laptop with pivoting, reversible display; dirt- and moisture-resistant system enclosure


On April 15, 2006, the first prototypes of the [[XO]], the [[XO_A|A1]] prototype boards, were first powered on. Development continued with the [[XO_B1|B1]], the first complete prototype laptop, in November of 2006. The [[XO_B2|B2]] laptops were the first to incorporate the CaFE chip, and was produced in small quantities for initial trials in January 2007. In April of 2008 the design was refreshed with a faster processor and more memory/NAND flash. The [[XO_B3|B3]] prototypes were the first test of this design. Slight refinements were incorporated into the [[XO_B4|B4]], manufactured in June 2008, which is very similar to the production version of the laptop. Finally, mass production started in November 2007 with the [[XO_C2|C2]] version.
''Core electronics:''
* CPU: [http://www.amd.com/us-en/ConnectivitySolutions/ProductInformation/0,,50_2330_9863_9864,00.html AMD Geode GX2-533@1.1W]
* CPU clock speed: 400 Mhz
* Compatibility: X86/X87-compatible
* Chipset: AMD CS5536 South Bridge
* Graphics controller: Integrated with Geode CPU; unified memory architecture
* Embedded controller: Based on ENE 3920
* DRAM memory: 128MB dynamic RAM
* Data rate: Dual – DDR266 – 133 Mhz
* BIOS: 512KB SPI-interface flash ROM; LinuxBIOS open-source BIOS
* Mass storage: 512MB SLC NAND flash
* Drives: No rotating media


Each prototype and production version is described in more detail separately: [[XO_A|A1]], [[XO_B1|B1]], [[XO_B2|B2]], [[XO_B3|B3]], [[XO_B4|B4]], [[XO_C1|C1]], '''[[XO_C2|C2]]'''
''Display:''
* Liquid-crystal display: 7.5” Dual-mode TFT display
* Viewing area: 151.6 mm × 113.4 mm
* Resolution: 1200 (H) × 900 (V) resolution (200 dpi)
* Mono display: High-resolution, reflective monochrome mode
* Color display: Standard-resolution, quincunx-sampled, transmissive color mode
* Special "DCON" chip, that enables deswizzling and anti-aliasing in color mode, while enabling the display to remain live with the processor suspended. Since we will always be running the frame buffer at 1200x900 resolution, the color resolution is lower, but exactly how this works out in effective resolution is complex. Mary Lou Jepsen is planning a document to explain the effective resolution, which is higher than if we simply reduced the size of the frame buffer and used the red, green and blue channels.


==Serial Adapter==
''Integrated peripherals:''
[[Image:serialadapter.jpg|100px|right]]
* Keyboard: 80 keys, 1.2mm stroke; sealed rubber-membrane key-switch assembly
* Cursor-control keys: Dual five-key cursor-control pads; four directional keys plus Enter
* Touchpad: Dual capacitance/resistive touchpad; supports written-input mode; vendor to be selected June 10
* Audio: Analog Devices AD1888, AC97-compatible audio codec; stereo, with dual internal speakers; monophonic, with internal microphone
* Wireless: Marvell 83W8388, 802.11b/g compatible; dual adjustable, rotating coaxial antennas; supports diversity reception
* Status indicators: Power, battery, WiFi; visible lid open or closed


In order to conserve parts/space, while the motherboard does provide two serial ports for debugging (one populated in production), it does not provide voltage translators to fully implement the RS-232 protocol. Thus a [[Serial_adapters|3.3V TTL to RS-232 (or USB) Adapter]] is needed.
''External connectors:''
* Power: 2-pin DC-input, 10 to 25 V, -23 to -10 V
* Line output: Standard 3.5mm 3-pin switched stereo audio jack
* Microphone: Standard 3.5mm 2-pin switched mono microphone jack; selectable sensor-input mode
* Expansion: 3 Type-A USB-2.0 connectors
* Maximum power: 500 mA (total)


<br clear="all">
''Battery:''
== Other Documents ==
* Pack type: 5 Cells, 6V series configuration
* Fully-enclosed “hard” case; user removable
* Capacity: 22.8 Watt-hours
* Cell type: NiMH
* Pack protection: Integrated pack-type identification
* Integrated thermal sensor
* Integrated polyfuse current limiter
* Cycle life: Minimum 1,000 charge/discharge cycles


* A complete [[Repair Parts]] List is under development.
''BIOS/loader:''
* [[Media:XO-1_Schematics.pdf|Schematics]]
* [http://www.linuxbios.org/index.php/Main_Page LinuxBIOS] is our intended BIOS for production units.


== See also ==
''Environmental specifications:''
Formerly part of this page:
* Temperature: somewhere in between typical laptop requirements and Mil spec; exact values have not been settled
* [[Hardware uniqueness]]
* Humidity: Similar attitude to temperature. When closed, the unit should seal well enough that children walking to and from school need not fear rainstorms or dust.
* [[Hardware design]]
* Maximum altitude: -15m to 3048m (14.7 to 10.1 psia) (operating), -15m to 12192m (14.7 to 4.4 psia) (non-operating
* [[Hardware modification]]
* 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)
* 2mm plastic walls (1.3mm is typical for most systems).


See also:
''Regulatory requirements:''
* [[Hardware Testing]]: Safety Certifications and Robustness
* The usual US and EU EMI/EMC requirements will be met.
* [[Hardware]]
* The laptop and all OLPC-supplied accessories will be fully UL and is RoHS compliant.
* [[Support]]

* The '''[[Media:CL1_Hdwe_Design_Spec.pdf|definitive laptop specification]]''' (only available in PDF format).
== What makes this system unique (relative to other systems called "laptops")? ==
[[category:Hardware]]

[[Category:XO-1]]
The machine is designed for young children, primarily ages 6-12. A large fraction of such children are in parts of the developing world where electricity is not available at home, or often even at school, so for many children, a low power consumption, potentially human powered computer is a necessity, not a convenience. Teaching may not even be inside, and certainly when children are at home, they often will not be inside where conventional LCD screens are usable. Children usually walk to and from school every day; weather is unpredictable, rain, dirt and dust are commonplace. And cost is a major consideration, if we are to bring computers and their great power to help children learn to children everywhere.

The design reflects these realities. It also reflects a great focus on what can and should be done to help bring the children the best possible learning tool.

* It is sized for a child, who, due to their size, will be closer to the screen than an adult with a conventional laptop. The system is much lighter than a conventional machine, (somewhere less than 1.5KG), and its industrial design is quite different than a commercial "black/grey/white" laptop. It has a rugged handle for carrying easily. This reflects the needs of children walking to and from school every day. The machine has a fun industrial design, something very different than a staid system for an adult, and is immediately recognizable as a "kids machine".
* It is a laptop. This seems like a stupid statement: but it is key; a child only spends a limited number of hours in school, and to maximize its use and the child's opportunity to learn, it must be able to be *their* computer, one they can take home and use where ever they are, whenever they have the opportunity. Computer labs of desktop systems, by contrast, can only be used at school, and are typically shared, further reducing the opportunity for learning.
* It has a novel dual mode screen, including grayscale high resolution mode that is reflective and can be used in bright sunlight, and much higher resolution that most LCD's. In this mode, no power is used by a backlight. In back-lit color mode, an LED backlight is used for much higher power efficiency than a conventional florescent backlight.
* It folds over into a "ebook", about the size of a conventional book, with buttons exposed for controlling viewer applications (or for use with games).
* The screen can be "on", allowing the CPU and most of the motherboard to be suspended, while the screen is read, allowing for major power savings in most common usage modes.
* The screen refresh rate can be varied. When applications are not changing the screen, we can reduce the refresh rate of the LCD to conserve power.
* The Marvell wireless chip can forward packets in the mesh network, with the CPU suspended, and the CPU may resume if explicitly addressed. Since the mesh network is so important, we want laptops to be able to participate in the mesh to keep forwarding packets when need be as efficiently as possible, and by suspending the processor we can increase the running time of the wireless a factor of 3-4. If this were not possible, children might need to disable wireless to preserve battery charge; by doing so, the mesh would be much less effective.
* The machine is rugged. The most common failures of laptops are disk drives, fans, florescent back lights, power connectors, connectors, and contamination of keyboards. Our machine uses flash, eliminating a disk, has no need for a fan, uses a rugged LED backlight rather than a florescent light, and uses a sealed rubber keyboard. It uses 2mm thick plastic, where a typical system might use 1.3mm. External connectors are carefully molded into the plastic for greater strength. The power connector is carefully chosen to be much more durable than usual, and again, the case is moulded carefully around it for greater strength. There are extremely few connectors in the machine, primarily just connecting the keyboard assembly to the motherboard (which is behind the LCD display). This eliminates most of the cables and connectors you will find in most laptops. Additionally, it allows us to almost directly connect the video output of the DCON chip to the LCD, enabling lower power drive of the screen. We will be testing 500 systems to destruction this fall to identify anything we can do to increase further its ruggedness.
* With these special power savings features, average power consumption, is expected to be low enough (in the neighborhood of 1-1.5 watts) that if a child needs to generate power for their laptop, they will get a good ratio of "work" to "learn". A small child can generate at best 5-10 watts; a larger child somewhat more. In contrast, conventional laptops often consume 20 watts or more, even when idle.
* When closed, the industrial design has a small lip to help seal the edge of the machine. While not water-proof, we expect a machine in a child's backpack or hands in a rainstorm should not have any problems with water.
* The keyboard is a rubber membrane keyboard, with quite nice feel (and we continue to work on further improvements on it). This makes the keyboard much more resiliant against both water and dirt, and allows us to seal the keyboard in the base of the machine. The keyboard is connected via a PS/2 interface to save power.
* A novel dual mode capacitive touch pad/resistive tablet compliments the keyboard. Besides a conventional touchpad, it can be used with a stylus for drawing, sketching, and learning to write.
* The audio codec can be used in a mode where direct voltage measurements can be taken, enabling children to learn about temperature, voltage, and many other physical phenomena with cheap sensors without requiring any external adaptors. The educational possibilities are limited only by your imagination.
* There are three USB2 connectors, allowing for many expansion possibilities.
* Mesh networking reduces the need for dedicated infrastructure (e.g. access points and/or cabling), and extends greatly the areas in which machines may be connected to each other and/or to the internet.
* Use of modern service discovery systems minimizes the need for central servers, particularly for common services such as chat. Children can network even when not able to connect to any school server, and work and socialize together.
* The wireless antennae are diversity antennae, and rotate upward using a rugged dual moulded nylon plastic design. When used rotated above the LCD, the antennae work significantly better than conventional built in antennae in existing systems or in Cardbus cards. This significantly increases the area each machine can cover in the mesh, and generally increases network performance. When closed, the antennae cover the audio and USB connectors to help keep dirt out of the connectors (as mentioned above, the case carefully moulds around the connectors, both to increase ruggedness and to help keep dirt and water out). Great care has been taken in the RF design, and early measurements show a lower noise level than seen by Marvell on any other design of theirs. We expect that the 802.11 networking in this system will be substantially better than a conventional system.
* The power supply is tolerant of almost any voltage you might have at hand for charging, either from a human powered generator or a car or truck battery; accidental reversal of polarity will not damage the machine.
* NiMH batteries are chosen to enable high charging efficiency from a generator (LiIon batteries require very close control of charging voltages, so any higher voltage would have to be clamped and power wasted). Additionally, NiMH batteries have no safety problems (LiIon batteries, when they fail, can fail by burning at extremely high temperature). And LiIon batteries should be recycled carefully. NiMH batteries pose no environmental concerns.
* Under typical use, the computer should last the entire school day without requiring charging. Avoiding disruption in class rooms, and/or the need for wiring in the class room for power (which may not even be available) is very important.
* Removable battery packs, that are relatively low cost. This enables easy swapping of batteries so that one set might charge while another are in use.

Note that while the original "green machine" showed a generator built into the system, further ergonomic research has shown that this would encourage the use of some of the weaker muscles in the body, and might also diminish the life of the machine as in order to generate efficiently, the machine might be held on a table top and sometimes fall to the ground. We also had noise and concerns about vibration concievably affecting LCD lifetime. External generators, if needed depending upon the location, can be much more efficient using much larger muscle groups and a number of different designs with different characteristics are being built by a number of organizations.

== Photographs of First Prototype Electronics ==

Power up of the first OLPC electronics prototype boards occurred April 15, 2006. Power and ground testing continued over the weekend, and formal debug and BIOS bring up started Monday, April 17, 2006 at Quanta Computer's labs in Taipei, Taiwan. By Wednesday, April 19, Linux was booting on the first generation prototypes.

* [[media:Proto-a-front.jpg|Component side OLPC circuit board]]
* [[media:Proto-a-back.jpg|Back side of the OLPC circuit board]]
* [[media:Proto-a-linux.jpg|Picture of Linux running with circuit board in the lab]]
* [[media:Proto-a-screen.jpg|Picture of the screen of Linux running on the OLPC circuit board; fittingly, it shows a Chinese desktop]]

== Second Generation Design ==

Second-generation unit will use a more power-efficient integrated Geode-based AMD chip (instead of the GX500/5536 set), presuming it is the best alternative available at the time, and probably a next generation wireless chip.

Latest revision as of 20:50, 15 July 2016

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The XO-1 laptop is a central focus of One Laptop Per Child. After three years of development, it entered mass production in November 2007. There are now millions of units deployed in the field, and thousands more with developers and for testing in schools all over the world. OLPC has developed newer hardware generations XO-1.5 and XO-1.75 that share the XO-1's industrial design.

Specifications

Drawing75c1.jpg
Dimensioned Drawing of XO, click to enlarge

The definitive laptop specification is only available in PDF format. This page attempts to accurately reflect that information. Note: this is the specification of the CL1A XO-1 production laptop. The specification for the earlier CL1 version (with the wide dual-mode touchpad) is here.

Physical dimensions

  • Approximate dimensions: 242mm × 228mm × 32mm (see drawing to the right for detailed dimensions)
  • Approximate weight:
    • XO laptop with LiFePO4 battery: 1.45KG (~3.20lbs);
    • XO laptop with NiMH battery: 1.58KG (~3.48lbs);
  • Configuration: Convertible laptop with pivoting, reversible display; dirt- and moisture-resistant system enclosure; no fan.

Core electronics

  • A photo of the XO-1 motherboard is available, with or without annotations.
  • CPU: x86-compatible processor with 64KB each L1 I and D cache; at least 128KB L2 cache;
  • CPU clock speed: 433 Mhz;
  • i586 instruction set (including MMX and 3DNow! Enhanced) with additional Geode-specific instructions
  • Companion chips: PCI and memory interface integrated with CPU;
    • North Bridge: PCI and Memory Interface integrated with Geode CPU (info)
    • South Bridge: datasheet
  • Graphics controller: Integrated with CPU; unified memory architecture;
  • Embedded controller: ENE KB3700 or ENE KB3700B;
  • DRAM memory: 256 MiB dynamic RAM; data rate: dual-DDR333-166Mhz;
  • BIOS: 1024KiB SPI-interface flash ROM;
  • Open Firmware used to load the operating system;
  • Mass storage: 1024 MiB SLC NAND flash; (a few "Red XOs" have been built with 2048 MiB of flash)
  • Drives: No rotating media.
  • CAFE ASIC (camera- and flash-enabler chip provides high-performance camera, NAND FLASH and SD interfaces); Marvell 88ALP01: CAFE Specification or local copy plus presence detect erratum
Prototype-A 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 at least 1024(H) × 768(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 are 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.
Etoys running on the first OLPC display prototype

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; 802.11s (Mesh) networking supported; dual adjustable, rotating antennas support diversity reception; capable of mesh operation when CPU is powered down;
  • 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 17 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 2-pin switched mono 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 or 4 cells LiFePO4; or 5 cells NiMH, approx. 6V series configuration (subject to change);
  • Capacity: 16.5 Watt-hours (NIMH), 22 Watt-hours (LiFeP);
  • 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.

Battery

BIOS/loader

  • 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;
  • 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

RoHS Restriction of Hazardous Substances Directive Logo.png
  • The usual US and EU EMI/EMC (electromagnetic-interference and electromagnetic-compatibility) requirements will be met;
  • The laptop meets IEC 60950-1, EN 60950-1, and CSA/UL 60950-1 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;
  • 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

On April 15, 2006, the first prototypes of the XO, the A1 prototype boards, were first powered on. Development continued with the B1, the first complete prototype laptop, in November of 2006. The B2 laptops were the first to incorporate the CaFE chip, and was produced in small quantities for initial trials in January 2007. In April of 2008 the design was refreshed with a faster processor and more memory/NAND flash. The B3 prototypes were the first test of this design. Slight refinements were incorporated into the B4, manufactured in June 2008, which is very similar to the production version of the laptop. Finally, mass production started in November 2007 with the C2 version.

Each prototype and production version is described in more detail separately: A1, B1, B2, B3, B4, C1, C2

Serial Adapter

Serialadapter.jpg

In order to conserve parts/space, while the motherboard does provide two serial ports for debugging (one populated in production), 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.


Other Documents

See also

Formerly part of this page:

See also:

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