Texas Instruments PCI7421 Subsystem ID Register, PC Card 16-bit I/F legacy-mode base-address

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

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