PORTIBM PC Portable (uses same BIOS as XT) 0CF8-0CFA - PCI Configuration Mechanism 2 - Configuration Registers Notes: this configuration mechanism is deprecated as of PCI version 2.1; only mechanism 1 should be used for new systems to access the configuration space, write the target bus number to the Forward Register, then write to the Configuration Space Enable register, and finally read or write the appropriate I/O port(s) in the range C000h to CFFFh (where Cxrrh accesses location 'rr' in physical device 'x's configuration data) the Intel "Saturn" and "Neptune" chipsets use configuration mechanism 2 SeeAlso: PORTIBM PC Portable (uses same BIOS as XT) 0CF8h"Mechanism 1",PORTIBM PC Portable (uses same BIOS as XT) C000h"PCI Configuration",PORTIBM PC Portable (uses same BIOS as XT) 0CFBh 0CF8 RW Configuration Space Enable (CSE) (see #P0945) 0CFA RW Forward Register (selects target bus number) Bitfields for PCI Configuration Space Enable: Bit(s) Description (Table P0945) 0 Special Cycle Enable (SCE) 3-1 target function number (PCI logical device within physical device) 7-4 key (non-zero to allow configuration) SeeAlso: #P0944