Reading the same PCF8574 IC pin get an output

Using Arduino Programming Questions
1

Hi,
I want to on the led when P6 pin HIGH and off the led when P6 pin LOW. But the LED doesn't on or off in any condition. Here is my code.

#define ARDUINO_H
#include <PCF8574.h>

//set i2c address
PCF8574 pcf8574_1(0x20);//create an instance of a PCF8574 object at 0x20 address

int OutPins[] = {13, 12};
int s;//Array element's parameter of OutPins[] array

void setup() {
  Serial.begin(9600);
  //set pinMode to INPUT
  pcf8574_1.pinMode(P0, INPUT);
  pcf8574_1.pinMode(P1, INPUT);
  pcf8574_1.pinMode(P2, INPUT);
  pcf8574_1.pinMode(P3, INPUT);
  pcf8574_1.pinMode(P4, INPUT);
  pcf8574_1.pinMode(P5, INPUT);
  pcf8574_1.pinMode(P6, INPUT);
  pcf8574_1.pinMode(P7, INPUT);

  pcf8574_1.begin();

  setupOutPins();//set the pinMode() function to LEDs

  digitalWrite ( OutPins[0], 1);
}

void setupOutPins() {
  for (s = 0; s < 2; s++) {
    pinMode (OutPins[s], OUTPUT);
    delayMicroseconds (100);
  }
}

void loop() {
  IncRead1 (); //Gives the output when the water level increasing in dip switch one
  DecRead1();//Gives the output when the water level decreasing in dip switch one
}

void IncRead1() {
 if(pcf8574_1.digitalRead(P0)==HIGH){
  Serial.println("Inc water level 1");
 }
  if (pcf8574_1.digitalRead(P6) == HIGH) {
    digitalWrite(OutPins[1], 1);
  }
}

void DecRead1(){
  if (pcf8574_1.digitalRead(P6) == LOW) {
    digitalWrite(OutPins[1], 0);
  }
}

Many thanks in advance.

2

What do your debug prints tell you?

3

TheMemberFormerlyKnownAsAWOL:
What do your debug prints tell you?

It wont led on or off when I write digitalWrite function high or low.(high to on low to off)

4

How to you have your LEDs wired up?
How to you have your inputs wired up?

Have you tested you can blink the LED without any of the other code? Make sure the LEDs are working properly before making your code more complex

5

PCF8574 chips cannot source a load, but only sink it. That means, to use it to drive a led, the led must be wired on the high side and is lit when the output of the PCF8574 pin is LOW.