SE7221BK1-ETechnical Product Specification

9.8Diagnostic LEDs

All port 80 codes are displayed using the Diagnostic LEDs found on the back edge of the baseboard. The diagnostic LED feature consists of a hardware decoder and four dual color LEDs. During POST, the LEDs will display all normal POST codes representing the progress of the BIOS POST. Each code will be represented by a combination of colors from the four LEDs.

The LEDs are capable of displaying three colors: Green, Red, and Amber. The POST codes are divided into two nibbles, an upper nibble and a lower nibble. Each bit in the upper nibble is represented by a Red LED and each bit in the lower nibble is represented by a green LED. If both bits are set in the upper and lower nibbles then both Red and Green LEDs are lit, resulting in an Amber color. If both bits are clear, then the LED is off.

In the below example, BIOS sends a value of ACh to the Diagnostic LED decoder. The LEDs are decoded as follows:

ƒRed bits = 1010b = Ah

ƒGreen bits = 1100b = Ch

Since the red bits correspond to the upper nibble and the green bits correspond to the lower nibble, the two are concatenated to be ACh.

Table 75. POST Progress Code LED Example

LEDs

Ach

Result

Red

 

Green

Red

Green

Red

Green

Red

 

Green

1

 

1

0

1

1

0

0

 

0

 

 

 

 

 

 

 

 

 

 

Amber

 

 

Green

 

Red

 

Off

 

 

 

 

 

 

 

 

 

 

 

MSB

 

 

 

 

 

LSB

 

 

 

 

 

 

 

 

 

 

9.8.1Diagnostic LED POST Progress Codes

 

 

 

 

 

 

 

 

Table 76. Boot Block POST Progress Codes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Diagnostic LED

 

Description

 

 

 

 

 

 

Decoder

 

 

 

 

 

 

 

G=Green, R=Red,

 

 

 

 

 

 

 

 

A=Amber

 

 

 

 

 

 

 

Hi

 

 

 

Low

 

 

 

 

10h

Off

 

Off

Off

R

 

The NMI is disabled. Start Power-on delay. Initialization code checksum

 

 

 

 

 

verified.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11h

Off

 

Off

Off

A

 

Initialize the DMA controller, perform the keyboard controller BAT test, start

 

 

 

 

 

memory refresh, and enter 4 GB flat mode.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

12h

Off

 

Off

G

R

 

Get start of initialization code and check BIOS header.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

13h

Off

 

Off

G

A

 

Memory sizing.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

14h

Off

 

G

Off

R

 

Test base 512K of memory. Return to real mode. Execute any OEM patches

 

 

 

 

 

and set up the stack.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

64

 

 

 

 

 

 

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Intel SE7221BK1-E manual Diagnostic LEDs, Diagnostic LED Post Progress Codes, Post Progress Code LED Example