pca9501 NXP Semiconductors, pca9501 Datasheet - Page 8

• Manufacturer Part Number: pca9501
• Description: 8-bit I2c And Smbus I/o Port With Interrupt, 2-kbit Eeprom And 6 Address Pins
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Interrupt (see Figs 9 and 12)
The PCA9501 provides an open drain output (INT) which can be fed
to a corresponding input of the microcontroller. This gives these
chips a type of master function which can initiate an action
elsewhere in the system.
An interrupt is generated by any rising or falling edge of the port
inputs in the input mode. After time t
Resetting and reactivating the interrupt circuit is achieved when data
on the port is changed to the original setting or data is read from or
written to the port which has generated the interrupt.
2004 Sep 30
8-bit I
2-kbit EEPROM and 6 address pins
DATA INTO I/O5
INT
2
C and SMBus I/O port with interrupt,
MICROCONTROLLER
SDA
SCL
START CONDITION
t iv
S
iv
INT
0
1
the signal INT is valid.
SLAVE ADDRESS (I/O EXPANDER)
Figure 10. Interrupt generated by a change of input to I/O5
Figure 9. Application of multiple PCA9501s with interrupt
A5
2
A4
3
V
DD
A3
4
A2
5
A1
PCA9501
6
INT
(1)
A0
7
R/W
8
1
8
Resetting occurs as follows:
Each change of the I/Os after resetting will be detected and, after
the next rising clock edge, will be transmitted as INT. Reading from
or writing to another device does not affect the interrupt circuit.
A
t ir
ACKNOWLEDGE
FROM SLAVE
In the READ mode at the acknowledge bit after the rising edge of
the SCL signal
In the WRITE mode at the acknowledge bit after the
HIGH-to-LOW transition of the SCL signal
Returning of the port data to its original setting.
Interrupts which occur during the acknowledge clock pulse may
be lost (or very short) due to the resetting of the interrupt during
this pulse.
PCA9501
INT
(2)
DATA FROM PORT
1
I/O5
PCA9501
INT
(16)
STOP CONDITION
1
PCA9501
Product data sheet
P
SW00790
SW00791