BTest-1 Release Notes

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This page contains hardware release notes for an early prototype of the XO laptop.

The Meaning of BTest-1

This is the beta test of fully functional hardware. There is typically one or two builds of systems internally before an external beta test, so our BTest-1 is really beta test for the electronics, while alpha test for the new screen, touch pad, industrial design, and keyboard; this is earlier in the development cycle than systems are usually made available, and is correspondingly rougher. The camera, SD slot and NAND flash are currently interfaced by an FPGA version of CaFE; the ASIC version is in BTest-2 and has significantly higher performance for both SD and NAND flash.

Hardware Specification

The BTest-1 laptops were built with an extra 128meg of RAM, to partially make up for well known memory problems in key applications, in particular the web browser, based on Firefox's Gecko technology. Work is well underway to reduce the browser's footprint; some of this work is visible in Firefox 2.0. BTest-2 will be built with 128 meg of RAM total.

Note that the BTest-1 systems use an Altera FPGA to implement that CaFE ASIC (which interfaces the camera, NAND flash and SD slot), which will not be available until the BTest-2 build. This has allowed us to test the design of CaFE and to build early systems more than 6 weeks sooner. Using an FPGA has several consequences: the FPGA consumes considerable power, and it is relatively slow. CaFE's NAND flash controller, while several times faster than on the Geode's controller on ATest boards, is still very slow relative to what it will be when implemented as an ASIC; similarly the SD controller is also slow relative to its eventual performance, both due the limitations on the speed of the FPGA, and since high speed mode for SD is just now being implemented in the device driver.

Instructions for Programming the Altera FPGA are available.

If for some reason you get bad data in the SPI boot FLASH so the system won't run the firmware, you can reload the SPI FLASH with a special cable.

The hardware specification is elsewhere in the wiki.

Hardware Release Notes

Our master list of hardware and mechanical issues and status can be found in the trac system we use. Please check this list before entering new issues: but please do enter issues you discover. The items below are the most significant from the list.

The battery charging algorithms have problems

The old EC code shipped with some units had a bug which prevented startup with low battery and another bug which prevented charging with a low battery. Updating to EC Q2B61 should fix most battery charging problems and please report any further difficulties. Please read this bug report for more information.

Inconsistent battery charge state indications

The EC can't report proper charging or capacity information and is overly conservative on the amount of power remaining, as the hardware chosen for the battery pack to report capacity is incorrect; this should be fixed in the BTest-2 build.

Keyboard keys occasionally stop working, and sometimes the machine does not reboot.

(ESD problem with the embedded controller.) One of the most irritating and noticeable problems is a static discharge problem that can lockup pins or entirely crash the embedded controller, causing some or all of the keyboard keys or touch pad to stop functioning. Power the machine off and on again to reset it (Note: you may need to remove and re-insert the battery to reset the EC completely). If your machine won't power on at all, remove the battery and make sure the machine is unplugged. Wait up to 10 minutes. We're not kidding; the EC takes very little power, and it can take a long time before everything has reset. Then replace the battery and plug it into the wall.

The resistive sensor does not work

(for use with a stylus for writing), due to a design flaw: The stylus pad area was disabled and should be fixed in BTest-2 machines

The arrow keys ("game keys") cannot be distinguished from the arrow keys on the keyboard

This will be fixed on BTest-2 system.

Manufacturing data values are in the wrong order

This is fixed the first time we update the BIOS SPI ROM, which should occur when you update the machine to current software on arrival.

Power management is as yet unimplemented

Therefore you cannot suspend and resume the machine (yet).

The internal microphone

does not work well as it is too near a speaker. It will be moved in BTest-3

The screen is covered by a plastic film by mistake

With care, it can be removed. Not every machine has this film and it is probably not worth the risk of damaging your machine to remove it if it is not really there to begin with.

Design Release Notes

The BTest-1 systems do not have textured plastic: this will happen in future builds.

Other design issues are also under investigation

Note that design is always an over constrained problem: it is often not possible to get every thing you would like in a design, though you can usually get most or all of what you value most.