/*
 * Setup and start codes for serial communications
 * 
 */

 volatile char* buffer;
 volatile int counts = 0 ;
 
// void setupSerial()
// {
//   setupSerialLib();
// }


// void startSerial()
// {
//   startSerialLib();
// }

// Read the serial port. Returns the read character in
// ch if available. Also returns TRUE if ch is valid. 
// This will be replaced later with bare-metal code.


// int readSerial(char *buffer)
// {

//   int count=readSerialLib(buffer);
  
//   // LCD Code
//   // if (count > 0) {
//   //   lcd.clear();
//   //   lcd.print("Received");
//   //   lcd.setCursor(0,1);
//   //   if (count >= 0) {
//   //     lcd.print(buffer[0], HEX);
//   //   }
//   //   if (count >= 1) {
//   //     lcd.print(buffer[1], HEX);
//   //   }
//   //   if (count >= 2) {
//   //     lcd.print(buffer[2], HEX);
//   //   }
//   //   if (count >= 3) {
//   //     lcd.print(buffer[3], HEX);
//   //   }
//   // }
  
//   return count;
// }

// Write to the serial port. Replaced later with
// bare-metal code

// void writeSerial(const char *buffer, int len)
// {
//   writeSerialLib(buffer, len);
// }

// /* --- Serial Library Version below --------------------------------------------------- */
// void setupSerialLib()
// {
//   // To replace later with bare-metal.
//   Serial.begin(9600);
//   // Change Serial to Serial2/Serial3/Serial4 in later labs when using the other UARTs
// }


// void startSerialLib()
// {
// }

// Read the serial port. Returns the read character in
// ch if available. Also returns TRUE if ch is valid. 
// This will be replaced later with bare-metal code.


// int readSerialLib(char *buffer)
// {

//   int count=0;

//   // Change Serial to Serial2/Serial3/Serial4 in later labs when using other UARTs

//   while(Serial.available())
//     buffer[count++] = Serial.read();
    
//   return count;
// }

// // Write to the serial port. Replaced later with
// // bare-metal code

// void writeSerialLib(const char *buffer, int len)
// {
//   Serial.write(buffer, len);
//   // Change Serial to Serial2/Serial3/Serial4 in later labs when using other UARTs
// }

/* --- USART Interrupt Version below -------------------------------------------------- */



// https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/ATmega640-1280-1281-2560-2561-Datasheet-DS40002211A.pdf


// int readUART( char* buffer ){
//   int counter = 0; 
//   char* recording;
  
//   while ( UCSR0A & (0b10000000) != 0){ // Check to see RXC0 register is 1 or 0 //
//     buffer[counter++] = UDR0;
//   }
  
//   return counter;  
// }

void writeUART( const char *buffer, int len){
  for ( int i = 0 ; i < len ; i ++ ){
    while ( !(UCSR0A & (1<< UDRE0))){}
    UDR0 = buffer[i];
  }
}



void setupUART()
{
  // UCSR0C = 0b00000110; // 0b 00(Async UART)_000_110
  
  // // Set Baud Rate to 
  // UBRR0H = 0;
  // UBRR0L = 103;
  // UCSR0A = 0;
  UBRR0H = 0;
  UBRR0L = 0b01100111;
  UCSR0A = 0;

  UCSR0B = (1 << RXEN0) | (1 << TXEN0);

  UCSR0C = (1<< UCSZ01) | (1 << UCSZ00);
}

void startUART()
{
  // UCSR0B = 0b10111000;
}

// ISR(USART_RX_vect)
// {
//   // receive data
//   _recvBuffer = UDR0;
// }

// Actual Interrupts //
// RECIEVE COMPLETE //
ISR(USART0_RXC){
  buffer[counts++] = UDR0;
  if (counts >= 7){ counts = 0; };
}

// TRANSFER COMPLETE //
ISR(USART0_TXC){

}

// UDR EMPTY HANDLER //
ISR(USART0_UDRE){

}


/* --- Sending Data ------------------------------------*/
/*
#define UDRIEMASK   0b00100000
ISR(USART_UDRE_vect)
{
  char data;
  TResult result = readBuffer(&_xmitBuffer, &data);
  
  if (result == BUFFER_OK) {
    UDR0 = data  
  } else if (result == BUFFER_EMPTY) {
    
  }
  // UDR0 = _xmitBuffer;
  UCSR0B &= ~UDRIEMASK;
}



void writeUART(const char *buffer, int len){
  TResult result = BUFFER_OK;
  int i;
  for (i=1; i<size && result == BUFFER_OK; i++){
    result = writeBuffer(&_xmitBuffer, line[i]);
  }
  
  // Start sending the first byte
  UDR0 = line[0]
  
  // Enable the UDRE interrupt. The enable bit is bit 5 of UCSR0B
  UCSR0B |= 0b0010000;
    
}
*/

void setup(){
  setupUART();
  startUART();
  // setupSerialLib();
  // startSerial();
}

void loop(){
  writeUART( "Hello World" , 11 );
  // readUART( buffer );
  writeUART( buffer, 11 );
  // writeSerial( "Hello World", 11);
  // readSerialLib(buffer);
  // writeSerial( buffer, 11 );
}