SOYO SY-7VCA user manual Debug LEDs, Code Explanation

Hardware Installation SY-7VCA

2-3.9 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			Explanation
X	X	X	L	Initialization of the chipset. The MCH and ICH registers will be set to the
				most conservative values by the BIOS to make sure the system boots up
D8	D3	D2	D1
				properly.
X	X	L	X	The BIOS is now decompressing the BIOS code into shadow RAM. Most of
				the BIOS code is stored in the BIOS Flash ROM IC in compressed form to
D8	D3	D2	D1	save space. At boot-up this code is decompressed and stored to RAM for faster
				execution.
X	X	L	L	The checksum for the decompressed code is calculated and checked. The
				checksum is calculated by adding all data bytes together and storing the result
D8	D3	D2	D1	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	L	X	X	The chipset (MCH and ICH) registers are set to the values selected by the user.
D8	D3	D2	D1
X	L	X	L	Now the BIOS will set the CPU Vcore voltage and the FSB bus frequency to
				the user selected value. If the system stops at this point, the settings selected
D8	D3	D2	D1
				by the user are inappropriate. Please select more conservative settings.
X	L	L	X	The Hardware Monitor Functionality is initialized. The settings the user
				selected in the BIOS for the Hardware Monitor are written into the Hardware
D8	D3	D2	D1
				Monitor registers.
X	L	L	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.
D8	D3	D2	D1
L	X	X	X	At this point the BIOS is initializing the CPU. The L2 cache latency values are
				set, and more important, the CPU micro-code is written into the CPU.
D8	D3	D2	D1
L	X	X	L	Now the system is testing the RAM inserted on the board. The screen will
				show the BIOS testing the RAM by a running counter. After finishing the test,
D8	D3	D2	D1
				the screen will show the amount of RAM in your system.
L	X	L	X	The super I/O registers are set to the default values. This includes the serial,
				parallel and IR etc settings.
D8	D3	D2	D1
L	X	L	L	At this point the IDE busses (primary and secondary) are scanned for devices.
D8	D3	D2	D1	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.
L	L	X	X	The serial and parallel port registers are set to the values selected by the user.
D8	D3	D2	D1
L	L	X	L	Now the BIOS will scan the peripheral busses for add-on cards. This includes
				the PCI and AGP busses. If any add-on cards are detected, the resources it
D8	D3	D2	D1
				requires are assigned by the BIOS in accordance with user settings.
L	L	L	X	The ESCD and DMI (Desktop Management Interface) values are checked. If
				there are changes, the BIOS will flash the new values into the BIOS Flash
D8	D3	D2	D1
				ROM IC.
L	L	L	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.
D8	D3	D2	D1

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