IDT88K8483 Integrated Device Technology, IDT88K8483 Datasheet - Page 123

• Manufacturer Part Number: IDT88K8483
• Description: Spi-4 Exchange Document Issue 1.0
• Manufacturer: Integrated Device Technology

PFP Egress Packet Mode Control Registers
PFP Link Number Configuration Register
PFP Buffer Management Configuration Register
PKT_MODE
EBP_EN
NR_LID
BUF_THR
OVBK_EN
IDT IDT88K8483
There are 64 registers, one for each LID.
Field
Field
Field
Table 102 PFP Buffer Management Configuration Register (Block Base=0x1700/0x1F00, Register Offset=0x01)
Table 100 PFP Egress Packet Mode Control Register (Block Base=0x1600/0x1E00, Register Offset=0x00-0x3F)
Table 101 PFP Link Number Configuration Register
R/W
R/W
R/W
R/W
R/W
Read /
Read /
Read /
Write
Write
Write
0:0
0:1
0:0-1:0
1:1
0:0-0:2
Bits
Bits
Bits
1
1
3
9
1
Length
Length
Length
0
0
0
0x1c0
0
Reset
Reset
Reset
State
State
State
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This field is used to program the PFP egress to interleaved mode or packet mode.
0: Interleaved mode. The LID is eligible to be served by the egress scheduler if
there is one or more packet fragment in the queue.The transfer unit is one packet
fragment.
1: Packet mode. The LID is eligible to be served by the egress scheduler if there are
one or more packets in the data memory.The transfer unit is one packet.
This control bit enables early backpressure propagation.
0: Normal backpressure.
1:Enable early backpressure propagation.
Link Identifier (LID) number configuration. Configures the maximum number of LIDs
that the application will use for this PFP data buffer. Once configured this value
should not be changed without resetting the IDT88K8483.
NR_LID Maximum number of LIDs
100
101
Indicates the global threshold for segmented data buffer at which the backpressure
is initiated. This field must be configured before the overbooking mode is enabled
(OVBK_EN = 1). Unit is the number of LIDs.
This indicates the manner in which the 508 data buffer segments in the PFP are
managed.
0: Non-overbooking mode.This means that the number of data buffer segments allo-
cated to each LID is limited by the M field in
(p.
1:Enable overbooking mode. This means that data buffer segments can now be
shared between LIDs up to 8 times the value of M if free segments are available.
000
001
010
011
(Block Base=
120).
1
4
8
16
32
64
0x1700/0x1F00
Description
Description
Description
, Register Offset=0x00)
PFP Buffer Segment Assign Table
October 20, 2006