User`s guide

4.2 21164 Address Mapping to PCI Space
Table 4–12 PCI Target Window Enables
PCI_MASK<31:20>
1
Size of Window
2
Value of n
3
0000 0000 0000 1MB 20
0000 0000 0001 2MB 21
0000 0000 0011 4MB 22
0000 0000 0111 8MB 23
0000 0000 1111 16MB 24
0000 0001 1111 32MB 25
0000 0011 1111 64MB 26
0000 0111 1111 128MB 27
0000 1111 1111 256MB 28
0001 1111 1111 512MB 29
0011 1111 1111 1GB 30
0111 1111 1111 2GB
4
31
1111 1111 1111 4GB
4
32
1
Combinations of bits in PCI_MASK<31:20> not shown in this table are not supported and produce
UNPREDICTABLE results.
2
Windows are not allowed to overlap.
3
Depending upon the target window size, only the incoming address bits <31:n> are compared with
bits <31:n> of the PCI base registers as shown in Figure 4–6 (n = 20 to 32). If n=32, no comparison
is performed. n is also used in Figure 4–7.
4
This size is not supported by the EB164.
Based on the value of the PCI mask register, the unmasked bits of the incoming
PCI address are compared with the corresponding bits of each window’s PCI
base register. If the base register and the incoming PCI address match, the
incoming PCI address has hit in that PCI target window; otherwise, it has
missed in that window. A window enable bit (WENB) is provided in each
window’s PCI base register to allow windows to be independently enabled or
disabled. If a window’s WENB bit is set, the window is enabled. The PCI
target windows must be programmed so that the PCI address ranges that each
one responds to do not overlap; otherwise, the results will be UNDEFINED.
The compare scheme between the incoming PCI address and the PCI base
register (along with the PCI mask register) previously described, is shown in
Figure 4–6.
System Address Mapping 4–21