PM7384 FREEDM-84P672
DATA SHEET
PMC-1990445
ISSUE 5
FRAME ENGINE AND DATA LINK MANAGER 84P672
BSAD[27:0]:
The Base Address (BSAD[27:0]) bits defines the size and location of the
memory space required for the CBI registers. The BSAD[27:0] bits
correspond to the most significant 28 bits of the PCI address space.
The size of the address space required can be determined by writing all ones to
Base Address register and then reading from it. By scanning the returned value
from the least significant bit upwards, the size of the required address space can
be determined. The binary weighted value of the first one bit found (after the
configuration bits) indicates the required amount of space. The BSAD[8:0] bits
are forced low to indicate that the CBI registers require 8K bytes of memory
space.
After determining the memory requirements of the CBI registers, the PCI Host
can map them to its desired location by modifying the BSAD[27:9] bits in the
Base Address register.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
293
PMC [ PMC-SIERRA, INC ]
