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168 | Appendix F: Diagnostic Code Checkpoints |
Diagnostic LED Decoder
Check
point
G=Green, R=Red, A+Amber Description
MSBLSB
B1 | R | OFF | R | A | Save system context for |
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| ACPI. |
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00 | OFF | OFF | OFF | OFF | Passes control to OS |
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| Loader (typically INT19h). |
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Bootblock Initialization Code Checkpoints
The Bootblock initialization code sets up the chipset, memory and other components before system memory is available. The following table describes the type of checkpoints that may occur during the bootblock initialization portion of the BIOS:
Check point
Diagnostic LED Decoder
G=Green, R=Red, A+Amber
MSB |
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| LSB |
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Description
Before D1 |
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| Early chipset initialization |
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| is done. Early super I/O |
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| initialization is done |
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| including RTC and |
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| keyboard controller. NMI |
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| is disabled. |
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D1 | R | R | OFF | A | Perform keyboard |
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| controller BAT test. Check |
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| if waking up from power |
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| management suspend |
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| state. Save |
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| CPUID value in scratch |
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| CMOS. |
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D0 | R | R | OFF | R | Go to flat mode with 4GB |
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| and GA20 enabled. Verify |
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| the bootblock checksum. |
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