qmk_firmware/LUFA/Drivers/Peripheral/Serial.h

/*
             LUFA Library
     Copyright (C) Dean Camera, 2010.

  dean [at] fourwalledcubicle [dot] com
           www.lufa-lib.org
*/

/*
  Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, distribute, and sell this
  software and its documentation for any purpose is hereby granted
  without fee, provided that the above copyright notice appear in
  all copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \file
 *  \brief Master include file for the USART peripheral driver.
 *
 *  Driver for the USART subsystem on supported USB AVRs.
 */

/** \ingroup Group_PeripheralDrivers
 *  @defgroup Group_Serial Serial USART Driver - LUFA/Drivers/Peripheral/Serial.h
 *
 *  \section Sec_Dependencies Module Source Dependencies
 *  The following files must be built with any user project that uses this module:
 *    - LUFA/Drivers/Peripheral/Serial.c <i>(Makefile source module name: LUFA_SRC_SERIAL)</i>
 *
 *  \section Module Description
 *  Hardware serial USART driver. This module provides an easy to use driver for
 *  the setup of and transfer of data over the AVR's USART port.
 *
 *  <b>Example Usage:</b>
 *  \code
 *      // Initialise the serial USART driver before first use, with 9600 baud (and no double-speed mode)
 *      Serial_Init(9600, false);
 *
 *      // Send a string through the USART
 *      Serial_TxString("Test String\r\n");
 *
 *      // Receive a byte through the USART
 *      uint8_t DataByte = Serial_RxByte();
 *  \endcode
 *
 *  @{
 */

#ifndef __SERIAL_H__
#define __SERIAL_H__

	/* Includes: */
		#include <avr/io.h>
		#include <avr/pgmspace.h>
		#include <stdbool.h>

		#include "../../Common/Common.h"
		#include "../Misc/TerminalCodes.h"

	/* Enable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			extern "C" {
		#endif

	/* Public Interface - May be used in end-application: */
		/* Macros: */
			/** Macro for calculating the baud value from a given baud rate when the U2X (double speed) bit is
			 *  not set.
			 */
			#define SERIAL_UBBRVAL(baud)    ((((F_CPU / 16) + (baud / 2)) / (baud)) - 1)

			/** Macro for calculating the baud value from a given baud rate when the U2X (double speed) bit is
			 *  set.
			 */
			#define SERIAL_2X_UBBRVAL(baud) ((((F_CPU / 8) + (baud / 2)) / (baud)) - 1)

		/* Function Prototypes: */
			/** Transmits a given string located in program space (FLASH) through the USART.
			 *
			 *  \param[in] FlashStringPtr  Pointer to a string located in program space.
			 */
			void Serial_TxString_P(const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);

			/** Transmits a given string located in SRAM memory through the USART.
			 *
			 *  \param[in] StringPtr  Pointer to a string located in SRAM space.
			 */
			void Serial_TxString(const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);

		/* Inline Functions: */
			/** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
			 *  standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
			 *
			 *  \param[in] BaudRate     Serial baud rate, in bits per second.
			 *  \param[in] DoubleSpeed  Enables double speed mode when set, halving the sample time to double the baud rate.
			 */
			static inline void Serial_Init(const uint32_t BaudRate,
			                               const bool DoubleSpeed)
			{
				UBRR1  = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));

				UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
				UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
				UCSR1B = ((1 << TXEN1)  | (1 << RXEN1));

				DDRD  |= (1 << 3);
				PORTD |= (1 << 2);
			}

			/** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
			static inline void Serial_ShutDown(void)
			{
				UCSR1B = 0;
				UCSR1A = 0;
				UCSR1C = 0;

				UBRR1  = 0;

				DDRD  &= ~(1 << 3);
				PORTD &= ~(1 << 2);
			}

			/** Indicates whether a character has been received through the USART.
			 *
			 *  \return Boolean true if a character has been received, false otherwise.
			 */
			static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
			static inline bool Serial_IsCharReceived(void)
			{
				return ((UCSR1A & (1 << RXC1)) ? true : false);
			}

			/** Transmits a given byte through the USART.
			 *
			 *  \param[in] DataByte  Byte to transmit through the USART.
			 */
			static inline void Serial_TxByte(const char DataByte) ATTR_ALWAYS_INLINE;
			static inline void Serial_TxByte(const char DataByte)
			{
				while (!(UCSR1A & (1 << UDRE1)));
				UDR1 = DataByte;
			}

			/** Receives a byte from the USART. This function blocks until a byte has been
			 *  received; if non-blocking behaviour is required, test for a received character
			 *  beforehand with \ref Serial_IsCharReceived().
			 *
			 *  \return Byte received from the USART.
			 */
			static inline char Serial_RxByte(void) ATTR_ALWAYS_INLINE;
			static inline char Serial_RxByte(void)
			{
				while (!(UCSR1A & (1 << RXC1)));
				return UDR1;
			}

	/* Disable C linkage for C++ Compilers: */
		#if defined(__cplusplus)
			}
		#endif

#endif

/** @} */