Philips ISP1521 ユーザーズマニュアル
Philips Semiconductors
ISP1521
Hi-Speed USB hub controller
Product data
Rev. 03 — 24 November 2004
43 of 53
9397 750 13702
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
[1]
f
SCL
=
1
⁄
64
×
f
XTAL
.
[2]
Rise time is determined by C
b
and pull-up resistor value R
p
(typical 4.7 k
Ω
).
Table 46:
Dynamic characteristics: I
2
C-bus (pins SDA and SCL)
V
CC
and T
amb
within recommended operating range; V
DD
= 5 V; V
SS
= V
GND
; V
IL
and V
IH
between V
SS
and V
DD
.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Clock frequency
f
SCL
SCL clock frequency
f
XTAL
= 12 MHz
0
93.75
100
kHz
General timing
t
LOW
SCL LOW time
4.7
-
-
µ
s
t
HIGH
SCL HIGH time
4.0
-
-
µ
s
t
r
SCL and SDA rise time
-
-
1000
ns
t
f
SCL and SDA fall time
-
-
300
ns
C
b
capacitive load for each bus line
-
-
400
pF
SDA timing
t
BUF
bus free time
4.7
-
-
µ
s
t
SU;STA
set-up time for (repeated) START
condition
condition
4.7
-
-
µ
s
t
HD;STA
hold time (repeated) START condition
4.0
-
-
µ
s
t
SU;DAT
data set-up time
250
-
-
ns
t
HD;DAT
data hold time
0
-
-
µ
s
t
SU;STO
set-up time for STOP condition
4.0
-
-
µ
s
Additional I
2
C-bus timing
t
VD;DAT
SCL LOW to data-out valid time
-
-
0.4
µ
s
Fig 16. I
2
C-bus timing.
P
S
Sr
P
004aaa485
tHD;STA
tBUF
tSU;STA
tSU;DAT
tf
tHIGH
tLOW
tSU;STO
tr
tHD;DAT
SDA
SCL