Who is ready to discuss Intel data sheets?

[logicman112]

I am studying Intel software developer data sheet and some questions come to the mind. Who can help me? Is there anybody interested in Intel chips like CPU and bridges?

 

[jsgruszynski]

I am studying Intel software developer data sheet and some questions come to the mind. Who can help me? Is there anybody interested in Intel chips like CPU and bridges?

Post a question and see what people respond to. It's too broad and vague a question otherwise.

 

[logicman112]

How a computer is shut down? (Pentium III, 815/ICH2). ATX power connector has PSON#. Sometimes I press the shut down button when the system is up and running but nothing happens.
I am actually looking for some block diagram to show the shut down process of a computer.

 

[chiro]

How a computer is shut down? (Pentium III, 815/ICH2). ATX power connector has PSON#. Sometimes I press the shut down button when the system is up and running but nothing happens.
I am actually looking for some block diagram to show the shut down process of a computer.

Are you talking about the protocol involved in the hardware? Good luck in finding that.

 

[logicman112]

We are going to explain exactly what happens when pressing the shut down switch. I have written the platform of our discussion(Pentium III, 815 and ICH2), All are ICs made by Intel. We want to find out if there is any power control IC on a motherboard? Or an auxiliary circuit? and probably the result of shut down is de-asserting PSON# for the power supply?

 

[jsgruszynski]

Usually the power switch, when the computer is already on, sends an interrupt to the OS and then OS decides when it's ready to actually shutdown. This allows it to flush files to disk, shutdown daemon processes in an orderly fashion, etc. This takes time so it doesn't shutdown right away.

 

[logicman112]

But the process of interrupt is not used after pressing the power switch for the first time. The first time it causes CPU fetches the instructions of BIOS and in the platform mentioned it causes the CPU fan starts working too.
That's why we need a block diagram to show the connection of the power switch and other ICs on a motherboard. It is very welcome if anybody finds a circuit or schematic for it.

 

[logicman112]

OK the first question was not answered but I ask the second one. Who knows about ACPI? BIOS prepares some ACPI tables and data structures. What does the operating system do with them?

 

[chiro]

OK the first question was not answered but I ask the second one. Who knows about ACPI? BIOS prepares some ACPI tables and data structures. What does the operating system do with them?

I used to write simple device drivers for DOS a very long time ago and what I'm about to say stems from that experience.

Typically the way you deal directly with the hardware is to either directly write to memory that is used by the hardware, or to write data to hardware ports. Interrupts could also be used, but I didn't do much with them when it came to restart/shutdown.

One idea that I think you should check out is to download the linux kernel and see its shutdown code (or any other relevant open source OS).