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Colibri PXA270 V2.x RAM Drive Strength Issue

 
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Issue Summary

The RAM drive strength settings configured in Windows CE bootloader versions older than V4.1 could lead to single bit RAM errors on the Colibri PXA270 V2.2B and 2.4A modules.

Affected Products

Product NumberProduct Name
00082201Colibri PXA270 312MHz V2.2B
00092201Colibri PXA270 520MHz V2.2B
00082400Colibri PXA270 312MHz V2.4A
00092400Colibri PXA270 520MHz V2.4A

Issue Description

During extensive burn-in tests on a particular combination of hardware and software revisions we identified a potential stability issue on a very low percentage of devices: At the limits of the temperature specification, single bit RAM errors occurred very rarely when running Eboot V4.0 and older on Colibri PXA270 V2.2B.

Potentially, PXA270 V2.4A modules could also be affected, although we were not able to produce any failure on any of these modules during our testing.

Colibri PXA270 V1.x modules are not affected.

Background Information

The currently configured signal drive strength for the RAM signal CLK1 could cause rare bit errors in the communication between CPU and RAM.

Solutions

Solution 1: Use Newer Bootloader (preferred)

Use the Windows CE bootloader Eboot V4.1 or newer which sets an optimized drive strength automatically. This is the preferred solution.

Solution 2: Use Older Bootloader

Continue to use an older bootloader and set the active drive strength in the bootloader configuration block. You can either set it manually through the bootloader menu or you can use a special tool to configure the correct value.

Run the ColibriPXA270FixMBS Tool

Deprecated: Please use V2.0 of this tool. See Colibri PXA270 V2.4C RAM Drive Strength Settings for details. You can use the ColibriPXA270FixMBS.exe tool which was developed to fix the issue described on this page.

The tool evaluates the module HW version and changes the drive strength setting in the config block only if required. Therefore it's safe to run this tool on any Colibri module HW and BSP version.

The changes are stored to the config block and also directly applied to the running system. A reboot isn't necessary.

There are two versions of this tool in the zip file below

  • ColibriPXA270FixMBS.exe
    shows a message box about the modification
  • ColibriPXA270FixMBS_unattended.exe
    runs quietly without any message, making it best suited for field upgrades

You can use the AutoRun feature of the Toradex Windows CE images to automatically execute this tool when attaching any mass storage device like USB Memory Stick, SD Card, etc. Just create a folder called AutoRun in the root directory of the storage device and copy the desired tool into this folder. This allows you to easily fix the settings on your modules running in the field.

Manually change the Configuration in the Config Block

Don't use this procedure on Colibri PXA270 V1.x modules. They require a different setting.
You can edit the config block through the bootloader menu's command prompt or by using the latest config block editor tool (V0.6 or newer). The following example shows the commands in the command prompt mode of the bootloader:

Used Commands:
SPACE             // to enter bootloader menu
x                 // to enter command prompt mode
set mbs.clk1=15   // to set the new drive strength value
save mbs          // to save the change to flash
Perform a reboot to apply the settings

The bootloader output should look like this when using the commands above:
Toradex Bootloader 4.1 for Colibri Built Sep 14 2012

Press [SPACE] to enter Bootloader Menu

BootLoader Configuration:

C) Clear Flash Registry
X) Enter CommandPrompt Mode
D) Download image to RAM now
F) Download image to FLASH now
L) Launch existing flash resident image now

Enter your selection: x
>set mbs.clk1=15
>save mbs
>