PXB4340E Datasheet, PDF (24/185 Pages) Infineon Technologies AG – ICs for Communications

3;%  (
)XQFWLRQDO 'HVFULSWLRQ
7DEOH  8723,$ SULRULW\ OLVW^
XSVWUHDP
GRZQVWUHDP
UHFHLYH ),)2 ILOO OHYHO 
WKUHVKROG
UHFHLYH ),)2 ILOO XWRSLD WUDQVPLW ),)2 QRW XWRSLD WUDQVPLW
OHYHO ≥
IXOO
),)2 IXOO
WKUHVKROG
1 BR cell from downstream 1 utopia
2 LB cell from downstream
1 FM cell insertion
backpressure to
2 BR cell from upstream ^{adjacent device}
3 FM cell from downstream
3 LB cell from upstream
4 scan poll
4 scan poll
5 scan OAM insertion
5 scan OAM insertion
6 µP cell insertion
6 µP cell insertion
7 µP RAM access (RMW)
7 µP RAM access (RMW)
8 utopia
8 utopia
1) _{1 = highest priority, 8 = lowest priority}
XSVWUHDP GLUHFWLRQ WR VZLWFKLQJ QHWZRUN
ˆ†r…Ãpryy†
"!pryyÃiˆssr…
s‚…Ãihpxƒ…r††ˆ…r
s‚…prqÃv†r…‡v‚
‚sÃP6HÃpryy†





(%pryyÆuh…rqÃiˆssr…
s‚…ÃpryyÃqr€ˆy‡vƒyr‘vt
2$0
3URFHVVRUV
P6HÃpryy†
ˆ†r…Ãpryy†
—3,QWHUIDFH
GRZQVWUHDP GLUHFWLRQ WR 3+<
#pryyÃiˆssr…Ãs‚…
VUPQD6 Ãuhq†uhxr
#pryyÃiˆssr…Ãs‚…
VUPQD6 Ãuhq†uhxr
)LJXUH  &HOO %XIIHUV LQ 3;%  $23
The downstream transmit buffer also does forced OAM cell insertion by back-pressuring user
cells to the downstream receive interface and possibly to the previous chip. It is realized as
shared buffer of up to 24 queues, associated to the respective PHYs. The back-pressured user
cells are released in bursts of up to 687 Mbit/s when no other cells with higher priority according
to WDEOH  are present. These bursts must be stored by the downstream transmit buffer and
released to the PHYs according to their respective speed.
Data Sheet
2-24
04.2000