CAT9555WI-T1 CATALYST SEMICONDUCTOR, CAT9555WI-T1 Datasheet - Page 8

• Manufacturer Part Number: CAT9555WI-T1
• Description: IC, I/O EXPANDER, 16BIT, 400KHZ, SOIC-24
• Manufacturer: CATALYST SEMICONDUCTOR

Specifications of CAT9555WI-T1

• Chip Configuration: 16 Bit
• Bus Frequency: 400kHz
• Ic Interface Type: I2C, SMBus
• No. Of I/o's: 16
• Supply Voltage Range: 2.3V To 5.5V
• Digital Ic Case Style: SOIC
• No. Of Pins: 24
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Configuration Pulse
CAT9555
¯¯¯ : Interrupt Output
The open-drain interrupt output is activated when one of
the port pins configured as an input changes state
(differs from the corresponding input port register bit
state). The interrupt is deactivated when the input returns
to its previous state or the input port register is read.
Doc. No. MD-9003 Rev. J
INT
Shift Register
Shift Register
Shift Register
Read Pulse
Write Pulse
Data from
Data from
Data from
Register
Polarity
Write
Write
Configuration
D
C K
Register
FF
Q
Q
Figure 4. Simplified Schematic of I/Os
C K
D
Output Port
Register
FF
Q
Q
8
Since there are two 8-bit ports that are read
independently, the interrupt caused by Port 0 will not
be cleared by a read of Port 1, or vice versa.
Changing an I/O from an output to an input may cause
a false interrupt if the state of the pin does not match
the contents of the input port register.
Inversion Register
C K
C K
D
D
Input Port
Register
LATCH
Polarity
FF
Q
Q
Q
Q
Q1
Q2
Characteristics subject to change without notice
100kΩ
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Output Port
Register Data
I/O Pin
Input Port
Register Data
Polarity
Register Data
V CC
V SS
To INT