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:
tSOP = tHDD (next J) − tHDD(SOP)
(A) downstream hub delay (B) upstream hub delay
upstream
differential
data lines
hub delay
downstream
tHDD
hub delay
upstream
tHDD
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