This 8-bit input/output (I/O) expander for the two-line bidirectional bus (I2C) is designed for 2.5-V to 6-V VCC operation.

The PCF8574 device provides general-purpose remote I/O expansion for most microcontroller families by way of the I2C interface [serial clock (SCL), serial data (SDA)].

The device features an 8-bit quasi-bidirectional I/O port (P0–P7), including latched outputs with high-current drive capability for directly driving LEDs. Each quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. At power on, the I/Os are high. In this mode, only a current source to VCC is active.

Features:

• This is the I/O extended module, which use for I2C interface, you can use two of the module to extend 8 I/O.
• Support cascading, and you can use at most 8 modules to extend 64 I/O at the same time.
• Can be changed the address by set toggle switch
• PCB Size: 36 x 16mm/1.41*0.62"
• Every 2 seconds, make P0-P7 port output High level, Low level, and put 3 toggle switches to ON, the address of module is 0x27