272 lines
10 KiB
C
272 lines
10 KiB
C
/*
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LUFA Library
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Copyright (C) Dean Camera, 2017.
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dean [at] fourwalledcubicle [dot] com
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www.lufa-lib.org
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*/
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/*
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Copyright 2017 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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Permission to use, copy, modify, distribute, and sell this
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software and its documentation for any purpose is hereby granted
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without fee, provided that the above copyright notice appear in
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all copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of the author not be used in
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advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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The author disclaims all warranties with regard to this
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software, including all implied warranties of merchantability
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and fitness. In no event shall the author be liable for any
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special, indirect or consequential damages or any damages
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whatsoever resulting from loss of use, data or profits, whether
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in an action of contract, negligence or other tortious action,
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arising out of or in connection with the use or performance of
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this software.
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*/
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/** \file
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* \brief Serial USART Peripheral Driver (AVR8)
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*
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* On-chip serial USART driver for the 8-bit AVR microcontrollers.
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*
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* \note This file should not be included directly. It is automatically included as needed by the USART driver
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* dispatch header located in LUFA/Drivers/Peripheral/Serial.h.
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*/
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/** \ingroup Group_Serial
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* \defgroup Group_Serial_AVR8 Serial USART Peripheral Driver (AVR8)
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*
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* \section Sec_Serial_AVR8_ModDescription Module Description
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* On-chip serial USART driver for the 8-bit AVR microcontrollers.
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*
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* \note This file should not be included directly. It is automatically included as needed by the USART driver
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* dispatch header located in LUFA/Drivers/Peripheral/Serial.h.
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*
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* \section Sec_Serial_AVR8_ExampleUsage Example Usage
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* The following snippet is an example of how this module may be used within a typical
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* application.
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*
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* \code
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* // Initialize the serial USART driver before first use, with 9600 baud (and no double-speed mode)
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* Serial_Init(9600, false);
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*
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* // Send a string through the USART
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* Serial_SendString("Test String\r\n");
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*
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* // Send a raw byte through the USART
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* Serial_SendByte(0xDC);
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*
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* // Receive a byte through the USART (or -1 if no data received)
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* int16_t DataByte = Serial_ReceiveByte();
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* \endcode
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*
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* @{
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*/
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#ifndef __SERIAL_AVR8_H__
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#define __SERIAL_AVR8_H__
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/* Includes: */
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#include "../../../Common/Common.h"
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#include "../../Misc/TerminalCodes.h"
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#include <stdio.h>
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/* Enable C linkage for C++ Compilers: */
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/* Preprocessor Checks: */
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#if !defined(__INCLUDE_FROM_SERIAL_H) && !defined(__INCLUDE_FROM_SERIAL_C)
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#error Do not include this file directly. Include LUFA/Drivers/Peripheral/Serial.h instead.
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#endif
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/* Private Interface - For use in library only: */
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#if !defined(__DOXYGEN__)
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/* External Variables: */
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extern FILE USARTSerialStream;
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/* Function Prototypes: */
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int Serial_putchar(char DataByte,
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FILE *Stream);
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int Serial_getchar(FILE *Stream);
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int Serial_getchar_Blocking(FILE *Stream);
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#endif
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/* Public Interface - May be used in end-application: */
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/* Macros: */
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/** Macro for calculating the baud value from a given baud rate when the \c U2X (double speed) bit is
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* not set.
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*
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* \param[in] Baud Target serial UART baud rate.
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*
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* \return Closest UBRR register value for the given UART frequency.
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*/
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#define SERIAL_UBBRVAL(Baud) ((((F_CPU / 16) + (Baud / 2)) / (Baud)) - 1)
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/** Macro for calculating the baud value from a given baud rate when the \c U2X (double speed) bit is
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* set.
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*
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* \param[in] Baud Target serial UART baud rate.
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*
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* \return Closest UBRR register value for the given UART frequency.
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*/
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#define SERIAL_2X_UBBRVAL(Baud) ((((F_CPU / 8) + (Baud / 2)) / (Baud)) - 1)
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/* Function Prototypes: */
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/** Transmits a given NUL terminated string located in program space (FLASH) through the USART.
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*
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* \param[in] FlashStringPtr Pointer to a string located in program space.
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*/
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void Serial_SendString_P(const char* FlashStringPtr) ATTR_NON_NULL_PTR_ARG(1);
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/** Transmits a given NUL terminated string located in SRAM memory through the USART.
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*
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* \param[in] StringPtr Pointer to a string located in SRAM space.
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*/
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void Serial_SendString(const char* StringPtr) ATTR_NON_NULL_PTR_ARG(1);
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/** Transmits a given buffer located in SRAM memory through the USART.
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*
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* \param[in] Buffer Pointer to a buffer containing the data to send.
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* \param[in] Length Length of the data to send, in bytes.
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*/
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void Serial_SendData(const void* Buffer, uint16_t Length) ATTR_NON_NULL_PTR_ARG(1);
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/** Creates a standard character stream from the USART so that it can be used with all the regular functions
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* in the avr-libc \c <stdio.h> library that accept a \c FILE stream as a destination (e.g. \c fprintf). The created
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* stream is bidirectional and can be used for both input and output functions.
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*
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* Reading data from this stream is non-blocking, i.e. in most instances, complete strings cannot be read in by a single
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* fetch, as the endpoint will not be ready at some point in the transmission, aborting the transfer. However, this may
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* be used when the read data is processed byte-per-bye (via \c getc()) or when the user application will implement its own
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* line buffering.
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*
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* \param[in,out] Stream Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
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* and \c stdin will be configured to use the USART.
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*
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* \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
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*/
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void Serial_CreateStream(FILE* Stream);
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/** Identical to \ref Serial_CreateStream(), except that reads are blocking until the calling stream function terminates
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* the transfer.
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*
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* \param[in,out] Stream Pointer to a FILE structure where the created stream should be placed, if \c NULL, \c stdout
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* and \c stdin will be configured to use the USART.
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*
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* \pre The USART must first be configured via a call to \ref Serial_Init() before the stream is used.
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*/
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void Serial_CreateBlockingStream(FILE* Stream);
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/* Inline Functions: */
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/** Initializes the USART, ready for serial data transmission and reception. This initializes the interface to
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* standard 8-bit, no parity, 1 stop bit settings suitable for most applications.
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*
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* \param[in] BaudRate Serial baud rate, in bits per second. This should be the target baud rate regardless of the
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* \c DoubleSpeed parameter's value.
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* \param[in] DoubleSpeed Enables double speed mode when set, halving the sample time to double the baud rate.
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*/
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static inline void Serial_Init(const uint32_t BaudRate,
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const bool DoubleSpeed);
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static inline void Serial_Init(const uint32_t BaudRate,
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const bool DoubleSpeed)
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{
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UBRR1 = (DoubleSpeed ? SERIAL_2X_UBBRVAL(BaudRate) : SERIAL_UBBRVAL(BaudRate));
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UCSR1C = ((1 << UCSZ11) | (1 << UCSZ10));
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UCSR1A = (DoubleSpeed ? (1 << U2X1) : 0);
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UCSR1B = ((1 << TXEN1) | (1 << RXEN1));
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DDRD |= (1 << 3);
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PORTD |= (1 << 2);
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}
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/** Turns off the USART driver, disabling and returning used hardware to their default configuration. */
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static inline void Serial_Disable(void);
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static inline void Serial_Disable(void)
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{
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UCSR1B = 0;
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UCSR1A = 0;
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UCSR1C = 0;
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UBRR1 = 0;
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DDRD &= ~(1 << 3);
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PORTD &= ~(1 << 2);
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}
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/** Indicates whether a character has been received through the USART.
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*
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* \return Boolean \c true if a character has been received, \c false otherwise.
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*/
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static inline bool Serial_IsCharReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
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static inline bool Serial_IsCharReceived(void)
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{
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return ((UCSR1A & (1 << RXC1)) ? true : false);
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}
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/** Indicates whether there is hardware buffer space for a new transmit on the USART. This
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* function can be used to determine if a call to \ref Serial_SendByte() will block in advance.
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*
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* \return Boolean \c true if a character can be queued for transmission immediately, \c false otherwise.
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*/
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static inline bool Serial_IsSendReady(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
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static inline bool Serial_IsSendReady(void)
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{
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return ((UCSR1A & (1 << UDRE1)) ? true : false);
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}
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/** Indicates whether the hardware USART transmit buffer is completely empty, indicating all
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* pending transmissions have completed.
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*
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* \return Boolean \c true if no characters are buffered for transmission, \c false otherwise.
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*/
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static inline bool Serial_IsSendComplete(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
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static inline bool Serial_IsSendComplete(void)
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{
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return ((UCSR1A & (1 << TXC1)) ? true : false);
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}
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/** Transmits a given byte through the USART.
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*
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* \note If no buffer space is available in the hardware USART, this function will block. To check if
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* space is available before calling this function, see \ref Serial_IsSendReady().
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*
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* \param[in] DataByte Byte to transmit through the USART.
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*/
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static inline void Serial_SendByte(const char DataByte) ATTR_ALWAYS_INLINE;
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static inline void Serial_SendByte(const char DataByte)
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{
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while (!(Serial_IsSendReady()));
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UDR1 = DataByte;
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}
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/** Receives the next byte from the USART.
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*
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* \return Next byte received from the USART, or a negative value if no byte has been received.
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*/
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static inline int16_t Serial_ReceiveByte(void) ATTR_ALWAYS_INLINE;
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static inline int16_t Serial_ReceiveByte(void)
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{
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if (!(Serial_IsCharReceived()))
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return -1;
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return UDR1;
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}
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/* Disable C linkage for C++ Compilers: */
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#if defined(__cplusplus)
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}
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#endif
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#endif
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/** @} */
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