Intel CONTROLLERS 413808 - Manual (Page 556)

Intel
®
413808 and 413812—Peripheral Bus Interface Unit
Intel ® 413808 and 413812 I/O Controllers in TPER Mode
Developer’s Manual October 2007
556 Order Number: 317805-001US
9.3.3 Determining Block Sizes for Memory Windows
The memory window size can be determined by writing ones to the appropriate upper
bits of the limit register. The binary-weighted value of the first non-zero bit set in the
limit register indicates the size of the memory window. Table 366 describes the
relationship between limit register values and the byte sizes of the memory window.
As an example, assume that FFF0 0000H is written to the PBI Limit Register 0 (PBLR0).
Scanning upwards starting at bit 12, bit 20 is the first one bit found. The
binary-weighted value of this bit is 1,048,576, indicating a 1 Mbyte of memory window.
When programming the Base and Limit Registers for a memory window, the Base
Address always needs to be aligned the size of the memory window set in a limit
register. For a 1 Mbyte memory window, only bit 20 through bit 31 of the base address
from the PBI Base Address Register 0 (PBBAR0) are relevant to the PBI when decoding
Memory Window 0.
Warning:
A given PBI Base (PBBAR0-PBBAR1) and Limit (PBLR0-PBLR1) register pair should not
be modified during the time there is activity on the peripheral bus associated with that
particular peripheral memory window. For instance, following boot-up, code executing
from Peripheral Memory Window 0 may be used to modify the PBI Base and Limit
registers for Peripheral Memory Window 1, but not for Peripheral Memory Window 0.
Table 366. Memory Block Size Limit Register Values
Limit Register Value
a
a. Smallest Limit Register Value is 4 KBytes.
Size
(in Bytes)
Limit Register Value
Size
(in Bytes)
FFFFF000H 4K FF800000H 8 M
FFFFE000H 8K FF000000H 16 M
FFFFC000H 16K FE000000H 32 M
FFFF8000H 32K FC000000H
Address
Window
Closed.
FFFF0000H 64K F8000000H
FFFE0000H 128K F0000000H
FFFC0000H 256K E0000000H
FFF80000H 512K C0000000H
FFF00000H 1 M 80000000H
FFE00000H 2 M 00000000H
FFC00000H 4 M