
Hawk PCI Host Bridge & Multi-Processor Interrupt Controller
MVME5100 Single Board Computer Programmer’s Reference (6806800H17B
)
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during compelled PHB accesses. The interdependency between the assertion of AACK_ and
TA_ allows the PPC Slave to assert a retry to the processor in the event that the transaction is
unable to complete on the PCI side. It should be noted that any transaction that crosses a PCI
word boundary could be disrupted after only having a portion of the data transferred.
The PPC Slave cannot perform compelled burst write transactions. The PPC bus protocol
mandates that the qualified retry window must occur no later than the assertion of the first TA_
of a burst transaction. If the PHB was to attempt a compelled linkage for all beats within a burst
write, there is a possibility that the transaction could be interrupted. The interruption would
occur at a time past the latest qualified retry window and the PPC Slave would be unable to
retry the transaction. Therefore, all burst write transactions are posted regardless of the write
posting attribute within the associated map decoder register.
If the PPC Slave is servicing a posted write transaction and the PPC FIFO can accept the
transaction, the assertion of AACK_ and TA_ occurs as soon as the PPC Slave decode logic
settles out and the PPC bus protocol allows for the assertion. If the PPC FIFO is full, the PPC
Slave holds the processor with wait states (AACK_ will not be asserted) until there is room
within the PPC FIFO to store the pending transaction. The PPC Slave divides PPC command
types into three categories: address only, write, and read. If a command type is an address only
and the address presented at the time of the command is a valid PHB address, the PPC slave will
respond immediately by asserting AACK_. The PHB will not respond to address only cycles
where the address presented is not a PHB address. The response of the PPC Slave to command
types is listed in the table.
Table 2-2 PPC Slave Response Command Types
PPC Transfer Type
Transfer
Encoding
Transaction
ECOWX
10100
No Response
TLB Invalidate
11000
Addr Only
ECIWX
11100
No Response
LWARX
00001
Addr Only
STWCX
00101
Addr Only
TLBSYNC
01001
Addr Only
ICBI
01101
Addr Only
Reserved
1XX01
No Response
Summary of Contents for MVME5100
Page 1: ...MVME5100 Single Board Computer Programmer s Reference P N 6806800H17B July 2014...
Page 8: ...MVME5100 Single Board Computer Programmer s Reference 6806800H17B Contents 8 Contents Contents...
Page 16: ...MVME5100 Single Board Computer Programmer s Reference 6806800H17B 16 List of Figures...
Page 292: ...Hawk Programming Details MVME5100 Single Board Computer Programmer s Reference 6806800H17B 292...
Page 312: ...VMEbus Mapping Example MVME5100 Single Board Computer Programmer s Reference 6806800H17B 312...
Page 316: ...Related Documentation MVME5100 Single Board Computer Programmer s Reference 6806800H17B 316...
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