Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
413
Messaging Unit—Intel
®
81341 and 81342
provides a more detailed diagram of the usage of the Circular Queues.
Figure 44. Circular Queue Operation
High Address Memory
Incremented by
Incremented by
Read
Write
Read
Write
Outbound
Free
Incremented by
Incremented by
Outbound
Post
Incremented by
Incremented by
Inbound
Post
Incremented by
Incremented
Inbound
Free
External PCI Agent
Read
Write
Read
Write
Outbound
Inbound
Low Address Memory
External PCI Agent
hardware
hardware
hardware
by hardware
Queue Port
Queue Port
Intel XScale® processor
Head Pointer
Tail Pointer
Head Pointer
Tail Pointer
Head Pointer
Tail Pointer
Head Pointer
Tail Pointer
Intel XScale® processor
Intel XScale® processor
Intel XScale® processor
Intel XScale® processor
Intel XScale® processor
Intel XScale® processor Local Memory
B6215-01