Did I burn the DI s?

[tugalsan]

I accidently plug 12 Volt to GND of DI sockets.

Even though, I did not plugged any wire on DI, I am getting the below output. 
When I check it with Voltmeter, DIs is giving me 12V
Does that mean, I did burn the card? Or a code error?

code:

Code:

#include "PCF8574.h"

//I2C INPUT
TwoWire I2C_0 = TwoWire(0);
PCF8574 pcf8574_I1(&I2C_0, 0x24, 4, 5);
PCF8574 pcf8574_I2(&I2C_0, 0x25, 4, 5);
PCF8574 pcf8574_I3(&I2C_0, 0x21, 4, 5);
PCF8574 pcf8574_I4(&I2C_0, 0x22, 4, 5);

//I2C RELAY
TwoWire I2C_1 = TwoWire(1);
PCF8574 pcf8574_R1(&I2C_1, 0x24, 15, 13);
PCF8574 pcf8574_R2(&I2C_1, 0x25, 15, 13);
PCF8574 pcf8574_R3(&I2C_1, 0x21, 15, 13);
PCF8574 pcf8574_R4(&I2C_1, 0x22, 15, 13);

void setup_input() {
  for(int i=0;i<=7;i++){
    pcf8574_I1.pinMode(i, INPUT);
    pcf8574_I2.pinMode(i, INPUT);
    pcf8574_I3.pinMode(i, INPUT);
    pcf8574_I4.pinMode(i, INPUT);
  }
  pcf8574_I1.begin();
  pcf8574_I2.begin();
  pcf8574_I3.begin();
  pcf8574_I4.begin();
}

void setup_output() {
  for(int i=0;i<=7;i++)
  {
    pcf8574_R1.pinMode(i, OUTPUT);
    pcf8574_R2.pinMode(i, OUTPUT);
    pcf8574_R3.pinMode(i, OUTPUT);
    pcf8574_R4.pinMode(i, OUTPUT);
  }
  pcf8574_R1.begin();
  pcf8574_R2.begin();
  pcf8574_R3.begin();
  pcf8574_R4.begin();
  for(int i=0;i<=7;i++) {
    pcf8574_R1.digitalWrite(i, HIGH);
    pcf8574_R2.digitalWrite(i, HIGH);
    pcf8574_R3.digitalWrite(i, HIGH);
    pcf8574_R4.digitalWrite(i, HIGH);
  }
}

void setup_serial(){
  Serial.begin(115200);
  while (!Serial && (millis() < 3000));
}

void print_chip_arduino(){
  Serial.print(F("\n\n----------------\n\n"));
  Serial.print(F("ARDUINO_BOARD:"));
  Serial.println(String(ARDUINO_BOARD));
}

unsigned long currentTime = millis();
void refreshCurrentTime(){
    currentTime = millis();
}

void print_loopHeader(){
  Serial.print(F("---------"));
  Serial.print(F("t: "));
  Serial.print(String(currentTime));
  Serial.println(F(" ---------"));
}

void print_input(){
  for(int i=0;i<=7;i++) {
      bool input1 = pcf8574_I1.digitalRead(i);
      bool input2 = pcf8574_I2.digitalRead(i);
      bool input3 = pcf8574_I3.digitalRead(i);
      bool input4 = pcf8574_I4.digitalRead(i);
      Serial.print(F("i:"));
      Serial.print(String(i));
      Serial.print(F(" I1:"));
      Serial.print(String(input1));
      Serial.print(F(" I2:"));
      Serial.print(String(input2));
      Serial.print(F(" I3:"));
      Serial.print(String(input3));
      Serial.print(F(" I4:"));
      Serial.println(String(input4));
  }
}

void setup() {
  setup_input();
  setup_output();
  setup_serial();
  print_chip_arduino();
}

void loop() {
  refreshCurrentTime();
  print_loopHeader();
  print_input();
  delay(1000);
}

output:

Code:

---------t: 8096 ---------
i:0 I1:1 I2:1 I3:1 I4:1
i:1 I1:1 I2:1 I3:1 I4:1
i:2 I1:1 I2:1 I3:1 I4:1
i:3 I1:1 I2:1 I3:1 I4:1
i:4 I1:1 I2:1 I3:1 I4:1
i:5 I1:1 I2:1 I3:1 I4:1
i:6 I1:1 I2:1 I3:1 I4:1
i:7 I1:1 I2:1 I3:1 I4:1