XO 4 B1

From OLPC

Revision as of 02:15, 7 October 2012 by FGrose (Talk | contribs)
Jump to: navigation, search
  This page is monitored by the OLPC team.
XO-4 Touch Laptop Beta test model, also known as B-test or B1.

Contents

Description

The B1 was the first complete prototype of the XO-4 Touch. The B1 bring up happened in the middle of September, 2012. XO-4 B1 units all have prototype multi-touch touchscreens using touchscreen technology from Neonode.

Identification

  • Seven bumps (arranged in two rows) on the Hinge Cover, identical to the XO-1.75
    XO-1.75 Hinge Cover
    . This will change for production.
  • The display has a bezel which doesn't have any texture (it is slick), and it is 1mm deeper than earlier XO laptops.
  • The touchscreen light guide is clear. In production units, this will be tinted and appear deep purple/black.
  • Rev. C motherboard

B1 laptops were produced with a variety of keyboards. They are identified in the battery compartment as SKUs 291, 292, 293, or 294.

Photographs:

Actually an A2 motherboard. Changes are minor, however. To be updated soon

Software Support

XO-4 Block Diagram
  • The current Open Firmware release is Q7B02.
    • The Q7Bxx series of Open Firmware cannot be used with XO-4 A2 motherboards. Starting with XO-4 B1, the size of OFW is 2MBytes.
    • This will not work on an XO-1, XO-1.5, or XO-1.75. As with XO-1.75, Open Firmware and the EC firmware are separate --- Open Firmware contains a recent version of the EC firmware and will automatically update an older version given two sources of power, but a more recent version may actually be programmed into the EC.
  • The current EC Firmware release is 7.0.2.02.

It is strongly recommended that you have two sources of power (a charged battery and an external power source) when you upgrade your EC or Open Firmware. Failure to do so may require the use of an SPI programmer to recover your laptop.

Upgrading the EC code

Using Open Firmware and WiFi

  • requires Q7B01 or later
ok wifi name
ok flash-ec http:\\dev.laptop.org\pub\ec\cl4-7_0_2_01.img
Reading http:\\dev.laptop.org\pub\ec\cl4-7_0_2_01.img
Scan for: name found
Associate with: name 
DHCP got 10.0.0.170 
EC firmware verison: XO-EC 7 0.2.01
Erasing ...

Writing ...
fff0 
Verifying ...
fff0

Board powers down at this point due to EC restart. Power up manually.

Using Open Firmware

  • requires Q7B01 or later

Place the EC firmware on a USB key and type:

ok flash-ec u:firmware-name
EC firmware verison: XO-EC 7 0.2.01
Erasing ...

Writing ...
fff0 
Verifying ...
fff0

Board powers down at this point due to EC restart. Power up manually.

Upgrading OFW

Using a USB Stick

Place a recent release of the Q7XYY firmware onto a USB stick, and place it in one of the laptops USB ports. Provide external power to the laptop.

Interrupt the OFW boot process by pressing the ESC key.

Type (assuming a q7b02 release):

 flash u:\q7b02.rom

Reboot by holding down the power button once this is completed.

Using an SD Card

Place a recent release of the Q7XYY firmware onto an SD device, and place it in the external SD slot. Provide external power to the laptop.

Interrupt the OFW boot process by pressing the ESC key.

Type (assuming a q7b02 release):

 flash ext:\q7b02.rom

Reboot by holding down the power button once this is completed.

See SPI Flash Recovery using JTAG if necessary.

Upgrading Linux

Installing from Open Firmware

You will need the .zd version of the OS image. Download it, then:

  1. Place the image on a USB stick, and insert it into the XO-4 laptop's external SD slot.
  2. Get the Ok prompt,
  3. Install onto the internal SD card, type:
fs-update u:os1.zd

Installing from Linux using an XO-1.75

To install on an XO-1.75, boot an XO-1.75 to Linux, insert the SD card in the XO-1.75 external slot, then:

zcat os1.img.gz > /dev/mmcblk1

... and then power down, remove the SD card, and insert in the XO-4.

Installing from Open Firmware using an XO-1.75

You will need the .zd version of the OS image. Download it, then:

  1. Place the image on a USB stick, and insert it into the XO-1.75 laptop's USB port.
  2. Get the Ok prompt,

To install an image onto the external SD card, you need to type:

devalias fsdisk ext:0
fs-update u:\os1.zd

... and then power down, remove the SD card, and insert it in the XO-4.

Setting the Date

The simplest way to set the date after replacing/changing the RTC battery is boot into Open Firmware and type:

wifi <your_essid>
ntp-set-clock

Restrictions

There is a list of recommended modifications (ECOs).

We recommend that B1 motherboards use a heat spreader.

Disassembly

When disassembling the XO-4 B1, please be careful with the flex cable connecting the touchscreen to the motherboard. In particular, the connector used to connect the flex cable to the IR PCB on the bezel is relatively fragile. Instead of disconnecting the flex cable from the IR PCB, we recommend laying the bezel/touchscreen assembly on the keyboard, removing the display, then disconnecting the flex cable from the motherboard. This will be improved in the C1 version.

When reassembling the laptop, please be aware that proper operation of the touchscreen requires that it be flat. Don't expect it to work well if the bezel isn't properly attached to the laptop using the four screws underneath the bezel.

Display Screws

The display is attached to the mainframe using screws which are shorter than the ones used on previous XOs. If you use one of the "normal" length, you will damage the motherboard. This is being fixed.

White Screen at Boot

After sitting for a while (like in shipping), the laptop will refuse to boot. This presents a white screen to the user, followed eventually by the "alien invasion screen" showing the number 52. This is being tracked as ticket #12135.

Speakers

We are looking at several problems with the speakers.

Connectors

Be very careful with the speaker connectors, it is easy to pull the wires out of the plastic shell. The SKU293 supplier will be disqualified.

Rattles

The speakers are not properly attached, and are prone to rattle, especially after shipping. If yours rattles, we recommend using a heavy duty epoxy to glue it down. This will be fixed.

Second serial port

As with XO-1.75, there is a second serial port provided for deep debugging of kernel issues. Unlike XO-1.75, this serial port is not populated by default. If you need to use this serial port, you will have to populate CN23, and make sure that Q38, Q44, R408, R373, and R98 are also populated. Like the main serial port, this one operates at +3.3V (using a voltage translator on the motherboard, as the actual SoC pins only tolerate +1.8V).

Documentation

Supporting documentation for these boards (all in PDF):

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

See also:

Followed by

Preceded by

Changes

Personal tools
  • Log in
  • Login with OpenID
About OLPC
About the laptop
About the tablet
Projects
OLPC wiki
Toolbox