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PCI Bus Controller
Freescale Semiconductor
22-9
22
R
Reserved. Fixed to 0. Prior to the 2.2 PCI specification, this was the UDF (user defined features) supported bit.
0 Does not support UDF
1 Supported user defined features
21
66M
66 MHz capable. Fixed to 1. Indicates the PCI controller is 66 MHz capable.
20
C
Capabilities list. Fixed to 0. Indicates the PCI controller does not implement the new capabilities list pointer
configuration register in DWORD 13 of the configuration space.
19–10
Reserved, must be cleared.
9
F
Fast back-to-back transfer enable. Controls if the PCI controller as master can do fast back-to-back transactions to
different devices. Initialization software should set this bit if all targets are fast back-to-back capable.
0 Fast back-to-back transactions only allowed to the same device
1 The master is allowed to generate fast back-to-back transactions to different devices
8
S
SERR enable. Enables the PCI_SERR driver.
0 PCI_SERR driver disabled
1 PCI_SERR driver enabled
Note:
Address parity errors are reported only if this bit and the PER bit are set.
7
ST
Address and data stepping. Fixed to 0. Indicates the PCI controller never uses address/data stepping. Initialization
software should write a 0 to this bit location.
6
PER
Parity error response. Controls the device’s response to parity errors.
0 The device sets its parity error status bit (PE, bit 31) in the event of a parity error, but does not assert PCI_PERR
1 When a parity error is detected, the PCI controller asserts PCI_PERR
5
V
VGA palette snoop enable. Fixed to 0. Indicates that the PCI controller is not VGA compatible. Initialization software
should write a 0 to this bit location.
4
MW
Memory write and invalidate enable. Enables the
MEMORY
WRITE
AND
INVALIDATE
command.
0 Only
MEMORY
WRITE
command can be used
1 PCI controller-as-master may generate the
MEMORY
WRITE
AND
INVALIDATE
command
3
SP
Special cycle monitor or ignore. Determines whether or not to ignore PCI special cycles. Because PCI
controller-as-target does not recognize messages delivered via the special cycle operation, a value of 1 must never
be programmed to this register. This bit, however, is programmable.
2
B
Bus master enable. Indicates if the PCI controller has the ability to serve as a master on the PCI bus. A value of 1
indicates this ability is enabled. If the PCI controller is a master on the PCI bus, a 1 must be written to this bit during
initialization or the PCI controller does not operate as a PCI master. Configuration software reads this bit.
1
M
Memory access control. Controls the PCI controller’s response to memory space accesses.
0 The PCI controller does not recognize memory accesses
1 The PCI controller recognizes memory accesses
0
IO
I/O access control. Fixed to 0. This bit is not implemented because there is no PCI controller I/O type space
accessible from the PCI bus. The PCI base address registers are memory address ranges only. Initialization software
must write a 0 to this bit location.
Table 22-4. PCISCR Field Descriptions (continued)
Field
Description
Summary of Contents for MCF54455
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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 ...
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