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Philips Semiconductors
ISP1521
Hi-Speed USB hub controller
Product data Rev. 03 — 24 November 2004 42 of 53
9397 750 13702
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
Full-speed timing symbols have a subscript prefix ‘F’, low-speed timing a prefix ‘L’.
Fig 14. Hub differential data delay and SOP distortion.
mgr777
SOP distortion:
t
SOP
= t
HDD (next J)
− t
HDD(SOP)
(A) downstream hub delay (B) upstream hub delay
upstream
differential
data lines
hub delay
downstream
t
HDD
hub delay
upstream
t
HDD
downstream
differential
data lines
downstream
differential
data
upstream
differential
data
crossover
point
crossover
point
crossover
point
crossover
point
+3.3 V
0 V
+3.3 V
0 V
Full-speed timing symbols have a subscript prefix ‘F’, low-speed timing a prefix ‘L’.
Fig 15. Hub EOP delay and EOP skew.
mgr778
t
EOP+
t
EOP−
t
EOP+
t
EOP−
crossover
point
extended
crossover
point
extended
EOP delay:
t
EOP
= max (t
EOP−
, t
EOP+
)
EOP delay relative to t
HDD
:
t
EOPD
= t
EOP
− t
HDD
EOP skew:
t
HESK
= t
EOP+
− t
EOP−
(A) downstream EOP delay (B) upstream EOP delay
upstream
differential
data lines
downstream
port
crossover
point
extended
crossover
point
extended
upstream
end of cable
downstream
differential
data lines
+3.3 V
0 V
+3.3 V
0 V