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Philips Semiconductors
Maintenance and control device
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
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.
SLAVE ADDRESS (PTN3501)
SDA
S
0
A
A
5
START CONDITION
SCL
1
2
3
P3
OUTPUT
VOLTAGE
P3
PULL-UP
OUTPUT
CURRENT
Figure 13. Transient pull-up current I
SYMBOL
PARAMETER
t
Output data valid; C
pv
t
Input data setup time; C
ps
t
Input data hold time; C
ph
t
Interrupt input data valid time;
iv
C
L
t
Interrupt reset time; C
ir
2001 Jan 17
is active. An additional strong pull-up to V
DD
A
A2 A1
A0
0
A
4
3
R/W
ACKNOWLEDGE
FROM SLAVE
4
5
6
7
8
while P3 changes from LOW-to-HIGH and back to LOW
OHt
MIN
100 pF
L
100 pF
L
100 pF
L
100 pF
100 pF
L
allows fast rising edges into heavily loaded outputs.
DD
DATA TO PORT
1
A
P3
ACKNOWLEDGE
FROM SLAVE
I
OHt
TYP
–
–
0
–
4
–
–
–
–
–
7
Product specification
PTN3501
DATA TO PORT
0
A
P
P3
I
OH
SW00789
MAX
UNIT
4
–
–
4
4
s
s
s
s
s
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