pca9655e ON Semiconductor, pca9655e Datasheet - Page 13

• Manufacturer Part Number: pca9655e
• Description: Pca9655e Remote 16-bit I/o Expander For I2c Bus With Interrupt
• Manufacturer: ON Semiconductor

Interrupt Output
pin configured as an input changes state. The interrupt is
deactivated when the input pin returns to its previous state
or when the Input Port register is read (see Figure 9). A pin
configured as an output cannot cause an interrupt. Since
SCL
SDA
read from port 0
data into port 0
read from port 1
data into port 1
INT
Remark: Transfer of data can be stopped at any moment by a STOP condition. When this occurs, data present at the latest acknowledge
phase is valid (output mode). It is assumed that the command byte has previously been set to ’00’ (read Input Port register).
The open−drain interrupt output is activated when an I/O
START condition
S A6
1
t
2
v(INT_N)
A5A4 A3
slave address
3
4
5
A2 A1 A0 1 A
acknowledge
6
from slave
DATA 00
7
R/W
8
9
D
A
T
A
t
0 1
rst(INT_N)
Figure 10. Read from Input Port Register, Scenario 2
t
h(D)
D
A
I0.x
T
A
DATA 01
acknowledge
0 0
from master
A
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t
h(D)
D
DATA 02
A
I1.x
13
T
A
acknowledge
0 1
from master
t
each 8−bit port is read independently, the interrupt caused by
Port 0 will not be cleared by a read of Port 1 or the other way
around.
Remark: Changing an I/O from an output to an input may
cause a false interrupt to occur if the state of the pin does not
match the contents of the Input Port register.
su(D)
D
A
T
A
A
A
1 1
D
DATA 03
A
I0.x
T
A
acknowledge
3 0
from master
t
su(D)
A
D
A
D
I1.x
T
A
non acknowledge
A
T
A
2 1
2 1
from master
STOP condition
1
P