Arduino Buttons Matrix Midi

#include <MIDI.h>
MIDI_CREATE_DEFAULT_INSTANCE();

// Configuration of the button matrix
const int ROWS = 3; // Number of rows
const int COLS = 3; // Number of columns
const int rowPins[3] = {12, 11, 10}; // Row pins
const int colPins[3] = {4, 3, 2}; // Column pins
int buttonCState[ROWS][COLS] = {}; // Current state of the buttons
int buttonPState[ROWS][COLS] = {}; // Previous state of the buttons
unsigned long lastDebounceTime[ROWS][COLS] = {0}; // Last time debounce was done
unsigned long debounceDelay = 150; // Debounce delay

void setup() {
  Serial.begin(31250); // Standard baud rate for MIDI
  // Set row pins as inputs with pull-up resistors
  for (int i = 0; i < ROWS; i++) {
    pinMode(rowPins[i], INPUT_PULLUP);
  }
  // Set column pins as outputs
  for (int j = 0; j < COLS; j++) {
    pinMode(colPins[j], OUTPUT);
    digitalWrite(colPins[j], HIGH);
  }
}

void loop() {
  buttons();
}

void buttons() {
  for (int col = 0; col < COLS; col++) {
    digitalWrite(colPins[col], LOW); // Set the current column to LOW
    for (int row = 0; row < ROWS; row++) {
      buttonCState[row][col] = digitalRead(rowPins[row]); // Read the state of the row
      if ((millis() - lastDebounceTime[row][col]) > debounceDelay) {
        if (buttonPState[row][col] != buttonCState[row][col]) {
          lastDebounceTime[row][col] = millis();
          if (buttonCState[row][col] == LOW) {
            MIDI.sendNoteOn(row * COLS + col, 127, 1); // Send note ON
            Serial.print("row:");
            Serial.print(row);
            Serial.print(" col:");
            Serial.print(col);
            Serial.println(" button on");
          } else {
            MIDI.sendNoteOff(row * COLS + col, 0, 1); // Send note OFF
            Serial.print("row:");
            Serial.print(row);
            Serial.print(" col:");
            Serial.print(col);
            Serial.println(" button off");
          }
          buttonPState[row][col] = buttonCState[row][col];
        }
      }
    }
    digitalWrite(colPins[col], HIGH); // Reset the column to HIGH
  }
}