XO 1.5 A2

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XO-1.5 Laptop Alpha test model second A-Test, also known as A2.

Description

The A2 prototype motherboard is a revised version of the A1 motherboard, fixing many of the small problems encountered with the layout. OLPC should receive thirty of these around the second week of July, 2009. All are dedicated to development and testing, with about half going to hardware/firmware and half to Linux.

Supporting documentation for these boards are (in PDF):

• Pinouts
• Connector Locations
• GPIO Mappings
• EC Pinout
• EC Power On Sequence
• Power Distribution Diagram

These are the same as for A1 boards.

Please note that production boards will likely have different pin mappings and connector locations.

Identification

• Packaged in production CL1A (new touchpad) cases.
• No camera
• "XO-1.5", "A2", and a serial number hand-written in the battery compartment
• Motherboard only has a single SD slot, the external one. There are no internal WLAN SD or microSD slots.

Photographs:

Photograph coming soon

Software Support

XO-1.5 use Q3axx firmware releases.

Restrictions

Heat

We seem to be OK in this department. Most (all ?) A2 motherboards in laptops with a back present have heat spreaders. Closed up laptops without a heat spreader should not damage themselves (if they do, please file a Trac bug).

WLAN

A Marvell 8686 SDIO module is populated on the motherboard. Unfortunately, there is a pin (Card Detect) on the VX855 that has to be tickled for the SDIO interface to work, and wad forgot to hook it up. There is no software work-around, and while it is possible to reach that ball, it is a very difficult and risky (ruining the motherboard is the most likely outcome) procedure. Thanks to Gary Chiang, an outstanding engineer at Quanta, we have five laptops with functioning WLAN interfaces.

For others, we recommend a USB/Cat5 dongle.

NAND Flash

All boards are populated with a Phison PS3006 NAND Flash controller and two NAND Flash chips for testing, providing 4 GBytes. There is also an IDE connector populated on the "top" of the board (side with LCD connectors).

This is not the PATA Flash controller that will be present in the final XO-1.5

Power-On Issues

One A2 boards has shown a problem with reliably powering up.

If you encounter a short flash of red on the battery light (either with or without all the other LEDs flashing as well) this indicates that the laptop didn't power on for some reason. Please file a Trac ticket. All the A2 motherboards have had the +1.2V power sequencing ECO, a.k.a. the SR ECO.

I have tried the +1.2VSUS supply sequencing ECO for reliable power-on on the one A2 board showing problems, and while nailing the power sequencing, it didn't fix that board's startup problems.

Followed by

• B1

Preceded by

• A1