5−19
5.21 ExCA I/O Windows 0 and 1 Offset-Address Low-Byte Registers
These registers contain the low byte of the 16-bit I/O window offset address for I/O windows 0 and 1. The 8 bits of
these registers correspond to the lower 8 bits of the offset address, and bit 0 is always 0b.
Bit 7 6 5 4 3 2 1 0
Default 0 0 0 0 0 0 0 0
Register: ExCA I/O window 0 offset-address low-byte
Offset: CardBus socket address + 836h; ExCA offset 36h
Register: ExCA I/O window 1 offset-address low-byte
Offset: CardBus socket address + 838h; ExCA offset 38h
Type: Read-only, Read/Write
Default: 00h
5.22 ExCA I/O Windows 0 and 1 Offset-Address High-Byte Registers
These registers contain the high byte of the 16-bit I/O window offset address for I/O windows 0 and 1. The 8 bits of
these registers correspond to the upper 8 bits of the offset address.
Bit 7 6 5 4 3 2 1 0
Default 0 0 0 0 0 0 0 0
Register: ExCA I/O window 0 offset-address high-byte
Offset: CardBus socket address + 837h; ExCA offset 37h
Register: ExCA I/O window 1 offset-address high-byte
Offset: CardBus socket address + 839h; ExCA offset 39h
Type: Read/Write
Default: 00h
5.23 ExCA Memory Windows 0−4 Page Registers
The upper 8 bits of a 4-byte PCI memory address are compared to the contents of this register when decoding
addresses for 16-bit memory windows. Each window has its own page register, all of which default to 00h. By
programming this register to a nonzero value, host software can locate 16-bit memory windows in any 1 of 256
16-Mbyte regions in the 4-Gbyte PCI address space. These registers are only accessible when the ExCA registers
are memory-mapped; that is, these registers cannot be accessed using the index/data I/O scheme.
Bit 7 6 5 4 3 2 1 0
Default 0 0 0 0 0 0 0 0
Register: ExCA memory windows 0−4 page
Offset: CardBus socket address + 840h, 841h, 842h, 843h, 844h
Type: Read/Write
Default: 00h
