Intel Pentium III Processor/840, Manual, Page: 58 / 151

5-2 Intel
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Pentium
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III Processor/840 Development Kit Manual
BIOS Quick Reference
When a keyboard and video device are attached, system can display either a traditional character-
based PC BIOS display with memory count-up, or it can display a graphical POST with splash
screen and progress icons. Both POST displays accept a <DEL> key press to enter the setup screen,
and both display boot-time progress activity displays. The graphical display shows the status of file
system devices and even OEM-defined devices (when the OEM adapts the BIOS to a particular
OEM platform), but omits character-based PCI resource display. The text-based POST displays the
memory count-up and the PCI resource assignment table.
Figure 5-1 shows the format of the text-based POST display. The display is very similar if console
redirection through a COM port is used instead.
Figure 5-2 shows the graphical version of POST. The BIOS decompresses the main image, and can
display multiple overlaid graphics at various points in POST. The OEM can define the entire
sequence and control the timing of the system for an embedded application, and can arrange to
have different graphics displayed on each successive boot of the system. This feature is ideal for
embedded systems that must show evidence of operation during startup, while the application loads
underneath the splash screen. Once the application begins writing to the screen, the splash screen
relinquishes control, providing a seamless graphical progression for the end user.
Figure 5-1. BIOS POST Pre-Boot Environment