Header Type 0
Figure 22-1 on page 771 illustrates the format of a function's Header region (for functions other than PCI-to-PCI bridges and CardBus bridges). The registers marked in black are always mandatory. Note that although many of the configuration registers in the figure are not marked mandatory, a register may be mandatory for a particular type of device. The subsequent sections define each register and any circumstances wherein it may be mandatory.
Figure 22-1. Header Type 0
As noted earlier, this format is defined as Header Type 0. The registers within the Header are used to identify the device, to control its functionality and ...