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Philips Semiconductors Product specification
PTN3501Maintenance and control device
2001 Jan 17
7
Quasi-bidirectional I/Os (see Figure 13)
A quasi-bidirectional I/O can be used as an input or output without the use of a control signal for data direction. At power-on the I/Os are HIGH.
In this mode, only a current source to V
DD
is active. An additional strong pull-up to V
DD
allows fast rising edges into heavily loaded outputs.
These devices turn on when an output is written HIGH, and are switched off by the negative edge of SCL. The I/Os should be HIGH before
being used as inputs.
S 0 A2 A1 A0 0 A A ASDA
SCL
12345678
SW00789
ACKNOWLEDGE
FROM SLAVE
R/WSTART CONDITION ACKNOWLEDGE
FROM SLAVE
SLAVE ADDRESS (PTN3501)
DATA TO PORT
DATA TO PORT
1
P3
0
P3
P
P3
OUTPUT
VOLTAGE
P3
PULL-UP
OUTPUT
CURRENT
I
OHt
I
OH
A
5
A
4
A
3
Figure 13. Transient pull-up current I
OHt
while P3 changes from LOW-to-HIGH and back to LOW
SYMBOL
PARAMETER MIN TYP MAX UNIT
t
pv
Output data valid; C
L
≤ 100 pF – – 4 µs
t
ps
Input data setup time; C
L
≤ 100 pF 0 – – µs
t
ph
Input data hold time; C
L
≤ 100 pF 4 – – µs
t
iv
Interrupt input data valid time;
C
L
≤ 100 pF
– – 4 µs
t
ir
Interrupt reset time; C
L
≤ 100 pF – – 4 µs