/*
  serial.c - Low level functions for sending and recieving bytes via the serial port
  Part of Grbl v0.9

  Copyright (c) 2012-2015 Sungeun K. Jeon

  Grbl is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Grbl is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
*/
/* 
  This file is based on work from Grbl v0.8, distributed under the 
  terms of the MIT-license. See COPYING for more details.  
    Copyright (c) 2009-2011 Simen Svale Skogsrud
    Copyright (c) 2011-2012 Sungeun K. Jeon
*/ 

#ifndef serial_h
#define serial_h


#ifndef RX_BUFFER_SIZE
  #define RX_BUFFER_SIZE 128
#endif
#ifndef TX_BUFFER_SIZE
  #define TX_BUFFER_SIZE 64
#endif

#define SERIAL_NO_DATA 0xff

#ifdef ENABLE_XONXOFF
  #define RX_BUFFER_FULL 96 // XOFF high watermark
  #define RX_BUFFER_LOW 64 // XON low watermark
  #define SEND_XOFF 1
  #define SEND_XON 2
  #define XOFF_SENT 3
  #define XON_SENT 4
  #define XOFF_CHAR 0x13
  #define XON_CHAR 0x11
#endif

void serial_init();

// Writes one byte to the TX serial buffer. Called by main program.
void serial_write(uint8_t data);

// Fetches the first byte in the serial read buffer. Called by main program.
uint8_t serial_read();

// Reset and empty data in read buffer. Used by e-stop and reset.
void serial_reset_read_buffer();

// Returns the number of bytes used in the RX serial buffer.
uint8_t serial_get_rx_buffer_count();

// Returns the number of bytes used in the TX serial buffer.
// NOTE: Not used except for debugging and ensuring no TX bottlenecks.
uint8_t serial_get_tx_buffer_count();

#endif