MPC8544COMEDEV Freescale Semiconductor, MPC8544COMEDEV Datasheet - Page 1048

• Manufacturer Part Number: MPC8544COMEDEV
• Description: KIT DEV EXPRESS MPC8544COM
• Manufacturer: Freescale Semiconductor
• Type: MPUr

Specifications of MPC8544COMEDEV

• Contents: Board
• For Use With/related Products: MPC8544
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PCI Bus Interface
The PCI controller also provides a direct way to generate PCI interrupt-acknowledge transactions. Reads
from PCI INT_ACK at offset 0x008 generate PCI interrupt-acknowledge transactions. Note that processor
writes to these addresses do nothing.
17.4.2.12.2 Special-Cycle Transactions
The special-cycle command provides a mechanism to broadcast select messages to all devices on the PCI
bus. The special-cycle command contains no explicit destination address but is broadcast to all PCI agents.
When the PCI controller detects a write to PCI CFG_DATA, it checks the enable flag and the device
number in PCI CFG_ADDR. If the enable bit is set, the bus number corresponds to the local PCI bus (bus
number = 0x00), the device number is all ones (0b1_1111), the function number is all ones (0b111), and
the register number is zero (0b00_0000), then the PCI controller performs a special-cycle transaction on
the local PCI bus. If the bus number indicates a nonlocal PCI bus, the PCI controller performs a type 1
configuration cycle translation, similar to any other configuration cycle for which the bus number does not
match.
Aside from the special-cycle command (PCI_C/BE[3:0] = 0b0001) the address phase contains no other
valid information. Although there is no explicit address, PCI_AD[31:0] are driven to a stable state, and
parity is generated. During the data phase, PCI_AD[31:0] contain the special-cycle message and an
optional data field. The special-cycle message is encoded on the 16 least-significant bits (PCI_AD[15:0]);
the optional data field is encoded on the most-significant 16 lines (PCI_AD[31:16]). The special-cycle
message encodings are assigned by the PCI SIG steering committee. The current list of defined encodings
are provided in
Note that the PCI controller does not automatically issue a special-cycle message when it enters any of its
power-saving modes. It is the responsibility of software to issue the appropriate special-cycle message, if
needed.
Each receiving agent must determine whether the special-cycle message is applicable to itself. Assertion
of PCI_DEVSEL in response to a special-cycle command is not necessary. The initiator of the
special-cycle transaction can insert wait states but since there is no specific target, the special-cycle
message and optional data field are valid on the first clock PCI_IRDY is asserted. All special-cycle
transactions are terminated by master-abort; however, the master-abort bit in the initiator’s bus status
register is not set for special-cycle terminations.
17-64
MPC8544E PowerQUICC III Integrated Host Processor Family Reference Manual, Rev. 1
Table
17-51.
Table 17-51. Special-Cycle Message Encodings
0x0003–0xFFFF
PCI_AD[15:0]
0x0000
0x0001
0x0002
SHUTDOWN
HALT
x86 architecture-specific
—
Message
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