#include "Arduino.h" #include "PCF8574.h" // Set i2c address PCF8574 pcf8574(0x39); unsigned long timeElapsed; void setup() { Serial.begin(115200); pcf8574.pinMode(P0, OUTPUT); pcf8574.pinMode(P1, INPUT); pcf8574.begin(); } void loop() { uint8_t val = pcf8574.digitalRead(P1); if (val==HIGH) Serial.println("KEY PRESSED"); delay(50); }