PCA9534 I/O Expander

PCA9534 GPIO expander library for Particle devices with Particle like API calls. It makes working with PCA9534 I/O expander pins easier, with familiar functions like pinMode() and digitalWrite(). Refer to the datasheet for more information about the chip.

Usage

Connect an LED to PCA9534 pin 0 chip, add the PCA9534 library to your project and follow this simple example:

#include "PCA9534.h"

#define GPIO_PIN_LED 0

PCA9534 gpio;

void setup() {
  gpio.begin();
  gpio.pinMode(GPIO_PIN_LED, OUTPUT);
}

void loop() {
  gpio.digitalWrite(GPIO_PIN_LED, LOW); // LED On
  delay(500);
  gpio.digitalWrite(GPIO_PIN_LED, HIGH); // LED Off
  delay(500);
}

See the examples folder for more details.

Documentation

PCA9534

Creates a new PCA9534 class to manage a PCA9534 chip.

#include "PCA9534.h"
...
...
PCA9534 gpio;
...
...
void setup() {
  gpio.begin();
}

begin([i2caddr])

Initializes the device and performs initial I2C setup. This method should be called before any others are used.

Parameters:

Name	Type	Description
i2caddr	uint8_t	Sets the slave address of the PCA9534, defaults to 0x20.

void setup() {
  gpio.begin(0x20);
}

pinMode(pin, mode)

Configures the specified pin to behave either as an input, inverted input, or output.

Parameters:

Name	Type	Description
pin	uint8_t	Pin number whose mode you wish to set.
mode	uint8_t	Pin mode one of: INPUT, INPUT_INVERTED, or OUTPUT.

void setup() {
  gpio.begin();
  gpio.pinMode(0, OUTPUT);
}

digitalWrite(pin, value)

Writes a HIGH or a LOW value to a digital pin.

Parameters:

Name	Type	Description
pin	uint8_t	Pin number whose value you wish to set.
value	uint8_t	Pin value one of: HIGH, or LOW.

void loop() {
  gpio.digitalWrite(0, LOW);
  delay(500);
  gpio.digitalWrite(0, HIGH);
  delay(500);
}

digitalRead(pin)

Reads the value from a specified digital pin, either HIGH or LOW.

Note: when using INPUT_INVERTED on pinMode(), you will get the inverted status.

Parameters:

Name	Type	Description
pin	uint8_t	Pin number whose value you wish to get.

Returns:

uint8_t - The status of the pin either HIGH or LOW.

void loop() {
  uint8_t buttonStatus = gpio.digitalRead(1);
  if (buttonStatus == HIGH) {
    gpio.digitalWrite(0, LOW); // LED On
  } else {
    gpio.digitalWrite(0, HIGH); // LED Off
  }
}

LICENSE

Copyright 2017 Abdulrahman Saleh Khamis (original author) Licensed under the MIT license Copyright 2019 Jake Pring (modifier) Additions/Modifications licensed as GPLv3