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64 PCI-5565PIORC* Ultrahigh Speed Fiber-Optic Reflective Memory with Interrupts
Publication No. 500-9367855565-000 Rev. D.0
2-MByte boundary. For example, the BIOS could set the PCIBAR3 to $F7600000
(allowing a PCI window up to $F77FFFFF). This serves as the PCI Base Address
for PIO access to the local Reflective Memory address space. The firmware also
defaults setting the Remap Value to 0 at the beginning of the installed memory
address space. This gives the user application PIO access to the Reflective
Memory locations $00000000 up to $001FFFFF. The user application can set the
Local Base Address (Remap) register pointing to any valid window in the
installed memory. For example, the user application can write $00200000 to the
Remap register to access the second 2-MByte PCI PIO window. The register value
will be $00200001 since bit-0 is hardwired to 1. This gives the user application PIO
access to the Reflective Memory locations $00200000 up to $003FFFFF. The user
application uses the same PCIBAR3 window ranging from $F7600000 up to
$F77FFFFF.
NOTE
After writing a new value to the LAS1BA remap register, the user application should read the LAS1BA
remap register before accessing the new window. This ensures the new window mapping has taken
effect and subsequent memory accesses will be to the new memory window.
In summary, register LAS1RR is the range register corresponding to the size of the
PCI window and is read-only. Register LAS1BA is the writeable base address
register. It is used to remap or offset the PCI PIO window to access other sections
of the installed memory. The RFM-5565 firmware prevents the user from entering
an invalid Remap Value. The value written must be a multiple of the PCI window
size. For example, using a PCI window size of 2 MBytes with 64 MBytes of
installed memory means there are 32 valid base address settings from $00000000
to $03E00000, incrementing by $00200000 (all other bits are masked off when
written). Also, a 64-MByte card with a 64-MByte window has no valid base
address settings other than the default 0.
Since the PCI window size and the Remap register only affect PCI PIO accesses,
DMA (Local-to-PCI and PCI-to-Local) can be used normally to transfer up to
$7FFFFF bytes with another location on the PCI bus regardless of the Remap
value.