Acer G300 Series manual Additional Bus Checkpoints, High Byte

132 Appendix A: AMIBIOS POST Checkpoint Codes

Additional Bus Checkpoints

While control is inside the different bus routines, additional checkpoints are output to I/O port address 0080h as word to identify the routines being executed.

These are word checkpoints. The low byte of checkpoint is the system BIOS checkpoint where control is passed to the different bus routines.

The high byte of checkpoint indicates that the routine is being executed in different buses.

High Byte

The high byte of these checkpoints includes the following information:

Bits	Description
Bits 7-4	0000 Function 0.		Disable all devices on the bus.
	0001	Function 1.	Initialize static devices on the bus.
	0010	Function 2.	Initialize output devices on the bus.
	0011	Function 3.	Initialize input devices on the bus.
	0100	Function 4.	Initialize IPL devices on the bus.
	0101	Function 5.	Initiate general devices on the bus.
	0110	Function 6.	Initialize error reporting on the bus.
	0111	Function 7.	Initialize add-on ROMs for all buses.

Bits 3-0	Specify the bus
	0	Generic DIM Device Initialization Manager.
	1	Onboard System devices.
	2	ISA devices.
	3	EISA devices.
	4	ISA PnP devices.
	5	PCI devices.