PCI Bus Controller
Freescale Semiconductor
22-55
PCI inbound address translation allows address translation to any space in local memory (4 Gbytes of
address space). The target base address translation registers, PCITBATR
n
, specify the location of the
inbound memory window. These registers are described in
Section 22.4.2, “Configuration Interface.”
Address translation occurs for all enabled inbound transactions. If the PCITBATR
n
[EN] bit is cleared, the
PCI controller aborts all PCI memory transactions to that base address window.
NOTE
The PCI configuring master can program the PCIBAR
n
registers to
overlapping PCI addresses. The default address translation value is
PCITBATR5 in that case. It is not recommended to program overlapping
PCIBAR space or overlapping PCITBATRs. An overlap of the PCITBATR
n
registers can cause data write-over of lower PCIBAR data.
The initiator window base address registers, PCIIW
n
BTAR, decode internal bus addresses for PCI bus
transactions. The base address and base address mask values define the upper byte of address to decode.
The internal bus address space dedicated to PCI transactions can be mapped to three 16-Mbyte or larger
address spaces in the device. Initiator windows can be programmed to overlap, though not recommended.
Priority for the windows is 0, 1, 2. Initiator window 0 has priority over all others and window 1 has priority
over window 2.
In normal operation, software must not program either target address window translation register to
address initiator window space. In that event, a PCI controller-as-target transaction propagates through the
device’s internal bus and requests PCI bus access as the PCI initiator. The PCI arbiter could see the PCI
bus as busy (target read transaction in progress) and only a time-out frees the PCI bus.
Figure 22-44. Inbound Address Map
0
4G
Register Space
PCI Space
3G
2G
1G
PCI Space (Memory View)
ColdFire Processor Space
0
4G
System Memory
PCI Controller Memory
PCITBATR0
Address
Inbound
Translation
Base Address 0
PCI Controller
BAR0
3G
2G
1G
Translation
SDRAM Space
PCITBATR5
Address
Translation
PCI Controller Memory
PCI Controller
BAR5
Initiator
Windows
Inbound
Translation
Base Address5
Not
Recommended
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...