pxf4336 Infineon Technologies Corporation, pxf4336 Datasheet - Page 141

• Manufacturer Part Number: pxf4336
• Description: Abm Premium Atm Buf Fer Manager
• Manufacturer: Infineon Technologies Corporation

4.2.2.3
The Common Real-Time bypass (CRT) is denoted by the reserved logical queue
identifier QID = 0. The rate assigned to the CRT bypass is programmed in the same way
as the SB rates. The parameters CRTIntRate and CRTFracRate are described in
registers
4.2.2.4
The programming of the rate for the internal SDRAM refresh generator is done by
calculating the integer and fractional parts of the dimensionless value T
the SB formulas
T
internal SDRAM refresh generator according to:
Given values of RefreshPeriod = 64ms, RefreshCycles = 4096 then
at SYSCLK = 51.84 MHz, T
at SYSCLK = 60 MHz,
This renders PCR
In case additional bandwidth needs to be reserved (e.g. for multicast operation in sub-
sequent devices), a second maximum condition for parameter T
depending on the empty cell rate required for multicast bandwidth reservation.
The cell rate for the empty cell cycles PCR
T
“UECRI/DECRI” on Page 312
4.2.2.5
For each logical queue, an optional peak rate shaper can be programmed.
Each cell passing the PCR limiter needs at least 2 cell cycles to emit. This limits the
maximum PCR that can be shaped to:
The resolution of the PCR limiter is determined by the global parameter TstepC,
common for all shapers in an ABM-P core.
Data Sheet
empty
empty(f)
is constrained by the need to allow a minimum number of empty cell cycles for the
, referred to as ECIntRate and ECFracRate in the corresponding registers
“UCRTRI/DCRTRI” on Page 327
Programming the Common Real-Time Bypass
Programming the SDRAM Refresh Empty Cell Cycles
Programming the PCR Limiter
PCR
T
empty
(Equation (8)
R Smax
empty
≤
SYSCLK
------------------------------------------------------------------------- -
= 64000 [cells/s] in both cases.
=
32
T
SYSCLK
------------------------ -
empty
empty
×
RefreshCycles
32
and
and
×
= 25.3125, T
= 29.2968, T
RefreshPeriod
Equation
“UECRF/DECRF” on Page
×
1
-- -
2
141
and
empty
empty(i)
empty(i)
(9)).
[
cells s ⁄
“UCRTRF/DCRTRF” on Page
is programmed by setting T
= 25, T
= 29, T
]
empty(f)
empty(f)
Operational Description
313.
emptyMC
= 80
= 76
PXF 4336 V1.1
empty
can be derived
according to
empty(i)
2001-12-17
ABM-P
328.
(12)
(13)
and