How To Fix Corrupted Vpd Information; What If Your Board Has The Wrong Vpd; How To Fix Wrong Vpd Problems; Checksum Guidelines - SMART Embedded Computing MVME7100ET Programmer's Reference Manual

A.6

How to Fix Corrupted VPD Information

If you encounter corrupted VPD information, use the following method to fix the corrupted
data:
 The firmware is designed to reach the prompt with bad VPD.

Use the vpdEdit command to fix the VPD.
A.7

What if Your Board Has the Wrong VPD

If your board has the wrong VPD information, the following occurs:
 No warning message is displayed.
 Incorrect VPD information is seen as correct by the firmware.
 The board may hang during startup (no-start condition).
 The board may be very unstable if it reaches the prompt.
 Device drivers, diagnostic tests, and firmware commands may hang or fail in
unexpected ways.
A.8

How to Fix Wrong VPD Problems

If you suspect that your board has problems, as a result of wrong VPD information, select
SAFE mode by setting S1:1 ON and reboot the MVME7100ET. At this point, the firmware
will ignore all EEPROM contents. Use the vpdEdit command to change the VPD to the
correct parameters.
A.9

Checksum Guidelines

The next sections provide examples of CRC calculation and SPD checksum calculations.
A.9.1

Vital Product Data CRC Calculation

When computing the CRC this field (for example, 4 bytes) is set to zero. The CRC only
covers the range as specified in the size field (4-bytes). Integer values are formatted/stored
in big-endian byte ordering. The VPD CRC generation code is shown in the following
example.
/*
* vpdGenerateCRC - generate CRC data for the passed buffer
* description:
MVME7100ET Single Board Computer Programmer's Reference (6806800K88C)
Programmable Configuration Data
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