2-3.7 Debug Leds - SOYO SY-7ISA User Manual

Hardware Installation

2-3.7 Debug LEDs

The Debug LEDs give an indication of the status of the system during
boot-up. If the system does not boot-up properly, use the table below to
find out at what point in boot-up sequence the problem arises. A x means
the LED is off, a L means the LED is lit.
Code
X X X
LED4 LED3 LED2 LED1
X X L
LED4 LED3 LED2 LED1
X X L
LED4 LED3 LED2 LED1
X L X
LED4 LED3 LED2 LED1
X L X
LED4 LED3 LED2 LED1
X L L
LED4 LED3 LED2 LED1
X L L
LED4 LED3 LED2 LED1
L X X
LED4 LED3 LED2 LED1
L X X
LED4 LED3 LED2 LED1
L X L
LED4 LED3 LED2 LED1
L X L
LED4 LED3 LED2 LED1
L L X
LED4 LED3 LED2 LED1
L L X
LED4 LED3 LED2 LED1
L L L
LED4 LED3 LED2 LED1
L L L
LED4 LED3 LED2 LED1
Explanation
Initialization of the chipset. The MCH and ICH registers will be
L
set to the most conservative values by the BIOS to make sure the
system boots up properly.
The BIOS is now decompressing the BIOS code into shadow RAM. Most
X
of the BIOS code is stored in the BIOS Flash ROM IC in compressed
form to save space. At boot-up this code is decompressed and stored to
RAM for faster execution.
The checksum for the decompressed code is calculated and checked. The
L
checksum is calculated by adding all data bytes together and storing the
result in the BIOS ROM. If the calculated checksum is different from the
checksum stored in the ROM, the code stored in the FLASH ROM is
corrupted.
X
The chipset (MCH and ICH) registers are set to the values selected by the
user.
Now the BIOS will set the CPU Vcore voltage and the FSB bus frequency
L
to the user selected value. If the system stops at this point, the settings
selected by the user are inappropriate. Please select more conservative
settings.
The Hardware Monitor Functionality is initialized. The settings the user
X
selected in the BIOS for the Hardware Monitor are written into the
Hardware Monitor registers.
L
If the VGA card does not work or is not inserted at all, the system will
display this code for a short period of time.
At this point the BIOS is initializing the CPU. The L2 cache latency
X
values are set, and more important, the CPU micro-code is written into the
CPU.
Now the system is testing the RAM inserted on the board. The screen will
L
show the BIOS testing the RAM by a running counter. After finishing the
test, the screen will show the amount of RAM in your system.
X
The super I/O registers are set to the default values. This includes the
serial, parallel and IR etc settings.
At this point the IDE busses (primary and secondary) are scanned for
L
devices. This includes HD drives and ATAPI CD-ROM drives that are
connected to the IDE bus. After scanning the detected devices are
displayed on screen.
X
The serial and parallel port registers are set to the values selected by the
user.
Now the BIOS will scan the peripheral busses for add-on cards. This
L
includes the PCI and AGP busses. If any add-on cards are detected, the
resources it requires are assigned by the BIOS in accordance with user
settings.
The ESCD and DMI (Desktop Management Interface) values are checked.
X
If there are changes, the BIOS will flash the new values into the BIOS
Flash ROM IC.
L
At this point the BIOS passes control to the Operating System (OS). All
LEDs will be on and will stay on to indicate a successful boot.
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SY-7ISA