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MPC8240 Integrated Processor User’s Manual
PCI Bus Transactions
Figure 7-4. PCI Burst Read Transaction
7.4.2 PCI Write Transactions
This section describes PCI single-beat write transactions, and PCI burst write transactions.
A PCI write transaction starts with the address phase, occurring when an initiator asserts
FRAME. A write transaction is similar to a read transaction except no turnaround cycle is
needed following the address phase because the initiator provides both address and data.
The data phases are the same for both read and write transactions. Although not shown in
the figures, the initiator must drive the C/BE[3:0] signals, even if the initiator is not ready
to provide valid data (IRDY negated).
Figure 7-5 illustrates a PCI single-beat write transaction. Figure 7-6 illustrates a PCI burst
write transaction.
Figure 7-5. PCI Single-Beat Write Transaction
PCI_SYNC_IN
FRAME
IRDY
AD[0:31]
ADDR
DEVSEL
TRDY
C/BE[0:3]
Byte enables 1
DATA2
DATA1
CMD
Byte enables 2
PCI_SYNC_IN
FRAME
IRDY
AD[0:31]
ADDR
DEVSEL
TRDY
C/BE[0:3]
DATA
CMD
Byte enables
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...