Chapter 9. Message Unit (with I
2
O)
9-7
I
2
O Interface
Figure 9-4 shows an example of the message queues:
Figure 9-4. I
2
O Message Queue Example
Table 9-8 lists the queue starting addresses for the FIFOs.
The following subsections describe the inbound and outbound FIFOs of the I
2
O interface.
9.3.3.1 Inbound FIFOs
The I
2
O specification defines two inbound FIFOs—an inbound post_list FIFO and an
inbound free_list FIFO. The inbound FIFOs allow external PCI masters to post messages
to theMPC8240 processor core.
Table 9-8. Queue Starting Address
FIFO
Starting Address
Inbound free_list
QBA (specified in QBAR)
Inbound post_list
QBA + (1*FIFO size specified in MUCR)
Outbound post_list
QBA + (2*FIFO size specified in MUCR)
Outbound free_list
QBA + (3*FIFO size specified in MUCR)
Outbound
Queue
Port
Inbound
Queue
Port
PCI Master
PCI Master
PCI Master
PCI Master
Inbound
Free List
FIFO
Inbound
Post List
FIFO
Outbound
Free List
FIFO
Outbound
Post List
FIFO
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
MFA
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Message
Frame
Head Pointer
Tail Pointer
Head
Tail Pointer
Head
Tail
Head
Tail
System Memory
Local Memory
Read
Write
Write
Read
Pointer
Pointer
Pointer
Pointer
Pointer
Core Write
Processor
Core Read
Processor
Core Write
Processor
Core Read
Processor
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 ...