Intel S5520SC Dokumentacja Pobierz pdf (Strona 176)

Appendix E: POST Code Diagnostic LED Decoder Intel® Workstation Board S5520SC TPS

Revision 1.7

Intel order number: E39530-010

162

Appendix E: POST Code Diagnostic LED Decoder

During the system boot process, the BIOS executes a number of platform configuration

processes, each of which is assigned a specific hex POST code number. As each configuration

routine is started, the BIOS displays the POST code to the POST Code Diagnostic LEDs on the

back edge of the workstation board. To assist in troubleshooting a system hang during the

POST process, you can use the Diagnostic LEDs to identify the last POST process executed.

Each POST code is represented by eight amber Diagnostic LEDs. The POST codes are divided

into two nibbles: an upper nibble and a lower nibble. The upper nibble bits are represented by

Diagnostic LEDs #4, #5, #6 and #7. The lower nibble bits are represented by Diagnostics LEDs

#0, #1, #2, and #3. If the bit is set in the upper and lower nibbles, the corresponding LED lights

up. If the bit is clear, the corresponding LED is off.

Diagnostic LED #7 is labeled “MSB” (Most Significant Bit), and Diagnostic LED #0 is labeled

“LSB” (Least Significant Bit).

A. Diagnostic LED #7 (MSB LED) E. Diagnostic LED #3

B. Diagnostic LED #6 F. Diagnostic LED #2

C. Diagnostic LED #5 G. Diagnostic LED #1

D. Diagnostic LED #4 H. Diagnostic LED #0 (LSB LED)

Figure 55. Diagnostic LED Placement Diagram

In the following example, the BIOS sends a value of EDh to the diagnostic LED decoder. The

LEDs are decoded as follows:

Table 88. POST Progress Code LED Example

LEDs

Upper Nibble LEDs Lower Nibble LEDs

LED

8h 4h 2h 1h 8h 4h 2h 1h

Status ON ON ON ON ON ON OFF ON

Results

1 1 1 0 1 1 0 1

Eh Dh

1 2 ... 171 172 173 174 175 176 177 178 179 180 181 ... 191 192

Brak uwag

Intel S5520SC Dokumentacja Strona 176