#include <SPI.h>
#include <Wire.h>
#include <SC16IS752.h>
# define BUZZER 1

SC16IS752 i2cuart = SC16IS752(SC16IS750_PROTOCOL_I2C, 0x48);

#define baudrate_A 9600
#define baudrate_B 9600

String type = "w";

void setup() {
  Serial.begin(115200);
  pinMode(21, OUTPUT);
  digitalWrite(21, HIGH);

  i2cuart.begin(baudrate_A, baudrate_B);
  if (i2cuart.ping() != 1) {
    Serial.println("device not found");
    while (1);
  } else {
    Serial.println("device found");
  }

  i2cuart.pinMode(BUZZER, OUTPUT);
}

void loop() {
  if (type == "w") {
    Serial.println("writing");

    // WRITE
    i2cuart.write(SC16IS752_CHANNEL_B, 123);

    delay(1000);
  } else {
    Serial.println("reading");

    // READ
    if (i2cuart.available(SC16IS752_CHANNEL_B) > 0) {
      alertBuzzer();

      // read the incoming byte:
      char c = i2cuart.read(SC16IS752_CHANNEL_B);

      Serial.println(c);

      delay(1000);
    }
  }
}

void alertBuzzer() {
  for (int i = 0; i <= 255; i++) {
    i2cuart.digitalWrite(BUZZER, HIGH);
    delay(1);
    i2cuart.digitalWrite(BUZZER, LOW);
  }
}