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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Reference Number: 306262-004US
927
AHB Queue Manager (AQM)—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network
Processors
• Programmable queue size supported (queues may be configured for 16, 32, 64 or
128 word buffer)
• Maintains empty (E), nearly empty (NE), nearly full (NF), and full (F) status flags
on each of the queues 0-63
• Programmable queue watermarks for assessing NE and NF queue status flags
• Provides status flag information, E, NE, F and NF, for queues 0-31 to the NPEs via a
common Flag Bus
• Provides Underflow and Overflow Status Flags for each of the queues 0-31
• Programmable event status enable for queues 32-63
• Two Intel XScale processor interrupts, one for queues 0-31 and one for queues 32-
63
• Individual interrupt enables for each queue
• Programmable interrupt source for each of the queues 0-31 as the assertion or de-
assertion of 1 of 4 status flags, E, NE, NF or F
• NE status flag used as the interrupt source for each of the queues 32-63
• Provides read/write access to all queues, queue pointers, status flags, configuration
registers, interrupt registers and SRAM via the AHB
• SRAM core computes and checks parity and provides error registers
27.3
Block Diagram
shows a high level block diagram of the AQM and its connections. The flag
bus present(s) a unified flag bus to each of the NPE CCPs (Condition Coprocessors) that
are to be connected. AQM instantiations are driven from the AHB bus and all operations
Figure 207. AHB Queue Manager
B4305-01
NPE
M
Intel XScale
®
Core
AHB
AHB Queue Manager
Queue
Buffer
SRAM
Queue
Control
AHB
Slave
Config/Status
Registers
INT
FLAG BUS
EVENT BUS