Outbound Translation Window Register (Otwr) - Motorola MPC8240 User Manual

Bits Name
31 —
30–12 Outbound
memory base
address
11 – 0 —

3.3.3.4 Outbound Translation Window Register (OTWR)

The OTWR, shown in Figure 3-11 and Table 3-11, defines the outbound translation
window and outbound window size. The outbound window size in the OTWR sets the size
of both the outbound translation window in PCI memory space and the outbound memory
window in the processor address space. Software can alter the outbound translation base
address and the outbound translation window size during runtime. This allows software to
scroll through host memory or address alternate space as needed.
31
Figure 3-11. Outbound Translation Window Register (OTWR)—0x0_2308
Bits Name
31–12 Outbound Undefined R/W PCI memory address—the starting address for the outbound translation window.
translation
base address
11–5 — All 0s
4–0 Outbound All 0s
window size
Table 3-10. Bit Settings for OMBAR—0x0_2300
Reset
R/W
Value
1 R Reserved. The outbound memory window must reside in the upper
2 Gbytes of the MPC8240 address space.
Undefined R/W Processor address that is the starting address for the outbound
memory window. The outbound memory window must be aligned
based on the granularity specified by the outbound window size
specified in the OTWR.
All 0s R Reserved
Outbound Translation Base Address
Table 3-11. Bit Settings for OTWR—0x0_2308
Reset
R/W
Value
The outbound translation window should be aligned based on the granularity
specified by the outbound window size.
R Reserved
R/W Outbound window size—The outbound window size is encoded as N where the
window size is 2
window size is 1 Gbyte. Note that the outbound window size sets the size of both
the outbound memory window and the outbound translation window.
00000 Outbound address translation disabled
00001 Reserved
...
01010 Reserved
12
01011 2
13
01100 2
14
01101 2
...
30
11101 2
11110 Reserved
11111 Reserved
Note that the outbound memory window must not overlap with the EUMB.
Chapter 3. Address Maps
Description
Outbound Window Size
12 11
Description
N+1
bytes. The minimum window size is 4 Kbytes; the maximum
= 4 Kbyte window size
= 8 Kbyte window size
= 16 Kbyte window size
= 1 Gbyte window size
Address Translation
Reserved
0 0 0 0 0 0 0
5 4 0
3-17