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Supplier Description

Have you run out of I/O pins? This great module allows the user to expand up to 16 I/O using only two I/O for control! The PCF8575 is controlled through an I2C interface and features 16-bits of quasi-bidirectional input/output pins.

On board 3.3V level converter circuit, if you do not solder VCC-VDD pad, the PCF8575 level is 3.3V. If you solder it, the level will be the same with VCC.

Features

  • Available library: PCF8575
  • Working voltage: 2.5 - 5.5VDC
  • Working current: 100mA(MAX)
  • I2C address: 0x20(default),can be modified by soldering A1 and A2 selection pads.
  • 16 individually addressable pins.
  • Each pin configurable for input or output.
  • Open-drain interrupt output pin for input change interrupt.
  • Great for UNO R3 and other MCU to control simple relay, buzzer, button, led.

Size: 3.2cm x 2.1cm

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Datasheet

The I2C IO expander chip:

Result of an I2C scan:

Scanning...
I2C device found at address 0x20  !
done

Usage

To use as inputs, e.g. to detect the status of push buttons, use a pull-up resiston of 100K Ohm to the VCC and connect the button to the ground.

Be carefull with the software: writing a HIGH to a pin and connecting it to the ground is ok, but the chip will be damaged if you write a LOW and connect it to the VCC.

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