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4.27 Subsystem ID Register
The subsystem ID register, used for system and option card identification purposes, may be required for certain
operating systems. This register is read-only or read/write, depending on the setting of bit 5 (SUBSYSRW) in the
system control register (PCI offset 80h, see Section 4.29). When bit 5 is 0, this register is read/write; when bit 5 is
1, this register is read-only. The default mode is read-only. All bits in this register are reset by GRST
only.
If an EEPROM is present, then the subsystem ID and subsystem vendor ID is loaded from the EEPROM after a reset.
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name Subsystem ID
Type R R R R R R R R R R R R R R R R
Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Register: Subsystem ID
Offset: 42h (Functions 0, 1)
Type: Read-only, (Read/Write when bit 5 in the system control register is 0)
Default: 0000h
4.28 PC Card 16-Bit I/F Legacy-Mode Base-Address Register
The PCI7x21/PCI7x11 controller supports the index/data scheme of accessing the ExCA registers, which is mapped
by this register. An address written to this register is the address for the index register and the address+1 is the data
address. Using this access method, applications requiring index/data ExCA access can be supported. The base
address can be mapped anywhere in 32-bit I/O space on a word boundary; hence, bit 0 is read-only, returning 1 when
read. As specified in the PCI to PCMCIA CardBus Bridge Register Description specification, this register is shared
by functions 0 and 1. See the ExCA register set description in Section 5 for register offsets. All bits in this register
are reset by GRST
only.
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Name PC Card 16-bit I/F legacy-mode base-address
Type RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW
Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name PC Card 16-bit I/F legacy-mode base-address
Type RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW R
Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Register: PC Card 16-bit I/F legacy-mode base-address
Offset: 44h (Functions 0, 1)
Type: Read-only, Read/Write
Default: 0000 0001h