This 16-bit I/O expander for the two-line bidirectional bus
(I2C) is designed for 2.3-V to 5.5-V VCC
operation. It provides general-purpose remote I/O expansion for most microcontroller families via
the I2C interface [serial clock (SCL), serial data (SDA)].
The PCA9555 consists of two 8-bit Configuration (input or output selection), Input Port,
Output Port, and Polarity Inversion (active high or active low operation) registers. At power on,
the I/Os are configured as inputs. The system master can enable the I/Os as either inputs or
outputs by writing to the I/O configuration bits. The data for each input or output is kept in the
corresponding Input or Output register. The polarity of the Input Port register can be inverted
with the Polarity Inversion register. All registers can be read by the system master.
View datasheet View product folder