I-Bus IBC 2600, User Manual

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Appendix 1 - BIOS Messages
A1-14
IBC 2600 User’s Guide
ADDITIONAL BUS CHECKPOINTS
While control is in the different bus routines, additional checkpoints are
output to Port 80H as WORD to identify the routines being executed.
These are WORD checkpoints. The LOW BYTE of checkpoint is the sys-
tem BIOS checkpoint where control is passed to the different bus rou-
tines, and the HIGH BYTE of checkpoint indicates that the routine is
being executed in different buses.
The information included in the high and low bytes of these checkpoints
is detailed below.
HIGH BYTE
The additional bus checkpoints listed above include the following infor-
mation:
Bits Description
Bits 7-4 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 ROM’s 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