3 /************************************************************************
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4 Title: Interrupt UART library with receive/transmit circular buffers
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5 Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
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6 File: $Id: uart.h,v 1.7.2.5 2005/08/14 11:25:41 Peter Exp $
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7 Software: AVR-GCC 3.3
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8 Hardware: any AVR with built-in UART, tested on AT90S8515 at 4 Mhz
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9 Usage: see Doxygen manual
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10 ************************************************************************/
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13 * @defgroup pfleury_uart UART Library
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14 * @code #include <uart.h> @endcode
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16 * @brief Interrupt UART library using the built-in UART with transmit and receive circular buffers.
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18 * This library can be used to transmit and receive data through the built in UART.
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20 * An interrupt is generated when the UART has finished transmitting or
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21 * receiving a byte. The interrupt handling routines use circular buffers
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22 * for buffering received and transmitted data.
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24 * The UART_RX_BUFFER_SIZE and UART_TX_BUFFER_SIZE constants define
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25 * the size of the circular buffers in bytes. Note that these constants must be a power of 2.
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26 * You may need to adapt this constants to your target and your application by adding
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27 * CDEFS += -DUART_RX_BUFFER_SIZE=nn -DUART_RX_BUFFER_SIZE=nn to your Makefile.
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29 * @note Based on Atmel Application Note AVR306
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30 * @author Peter Fleury pfleury@gmx.ch http://jump.to/fleury
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36 #if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
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37 #error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
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42 ** constants and macros
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45 /** @brief UART Baudrate Expression
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46 * @param xtalcpu system clock in Mhz, e.g. 4000000L for 4Mhz
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47 * @param baudrate baudrate in bps, e.g. 1200, 2400, 9600
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49 #define UART_BAUD_SELECT(baudRate,xtalCpu) ((xtalCpu)/((baudRate)*16l)-1)
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51 /** @brief UART Baudrate Expression for ATmega double speed mode
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52 * @param xtalcpu system clock in Mhz, e.g. 4000000L for 4Mhz
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53 * @param baudrate baudrate in bps, e.g. 1200, 2400, 9600
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55 #define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) (((xtalCpu)/((baudRate)*8l)-1)|0x8000)
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58 /** Size of the circular receive buffer, must be power of 2 */
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59 #ifndef UART_RX_BUFFER_SIZE
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60 #define UART_RX_BUFFER_SIZE 32
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62 /** Size of the circular transmit buffer, must be power of 2 */
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63 #ifndef UART_TX_BUFFER_SIZE
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64 #define UART_TX_BUFFER_SIZE 32
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67 /* test if the size of the circular buffers fits into SRAM */
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68 #if ( (UART_RX_BUFFER_SIZE+UART_TX_BUFFER_SIZE) >= (RAMEND-0x60 ) )
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69 #error "size of UART_RX_BUFFER_SIZE + UART_TX_BUFFER_SIZE larger than size of SRAM"
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73 ** high byte error return code of uart_getc()
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75 #define UART_FRAME_ERROR 0x0800 /* Framing Error by UART */
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76 #define UART_OVERRUN_ERROR 0x0400 /* Overrun condition by UART */
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77 #define UART_BUFFER_OVERFLOW 0x0200 /* receive ringbuffer overflow */
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78 #define UART_NO_DATA 0x0100 /* no receive data available */
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82 ** function prototypes
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86 @brief Initialize UART and set baudrate
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87 @param baudrate Specify baudrate using macro UART_BAUD_SELECT()
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90 extern void uart_init(unsigned int baudrate);
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94 * @brief Get received byte from ringbuffer
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96 * Returns in the lower byte the received character and in the
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97 * higher byte the last receive error.
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98 * UART_NO_DATA is returned when no data is available.
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101 * @return lower byte: received byte from ringbuffer
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102 * @return higher byte: last receive status
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103 * - \b 0 successfully received data from UART
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104 * - \b UART_NO_DATA
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105 * <br>no receive data available
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106 * - \b UART_BUFFER_OVERFLOW
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107 * <br>Receive ringbuffer overflow.
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108 * We are not reading the receive buffer fast enough,
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109 * one or more received character have been dropped
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110 * - \b UART_OVERRUN_ERROR
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111 * <br>Overrun condition by UART.
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112 * A character already present in the UART UDR register was
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113 * not read by the interrupt handler before the next character arrived,
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114 * one or more received characters have been dropped.
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115 * - \b UART_FRAME_ERROR
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116 * <br>Framing Error by UART
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118 extern unsigned int uart_getc(void);
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122 * @brief Put byte to ringbuffer for transmitting via UART
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123 * @param data byte to be transmitted
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126 extern void uart_putc(unsigned char data);
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130 * @brief Put string to ringbuffer for transmitting via UART
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132 * The string is buffered by the uart library in a circular buffer
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133 * and one character at a time is transmitted to the UART using interrupts.
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134 * Blocks if it can not write the whole string into the circular buffer.
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136 * @param s string to be transmitted
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139 extern void uart_puts(const char *s );
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143 * @brief Put string from program memory to ringbuffer for transmitting via UART.
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145 * The string is buffered by the uart library in a circular buffer
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146 * and one character at a time is transmitted to the UART using interrupts.
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147 * Blocks if it can not write the whole string into the circular buffer.
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149 * @param s program memory string to be transmitted
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153 extern void uart_puts_p(const char *s );
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156 * @brief Macro to automatically put a string constant into program memory
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158 #define uart_puts_P(__s) uart_puts_p(PSTR(__s))
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162 /** @brief Initialize USART1 (only available on selected ATmegas) @see uart_init */
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163 extern void uart1_init(unsigned int baudrate);
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164 /** @brief Get received byte of USART1 from ringbuffer. (only available on selected ATmega) @see uart_getc */
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165 extern unsigned int uart1_getc(void);
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166 /** @brief Put byte to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_putc */
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167 extern void uart1_putc(unsigned char data);
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168 /** @brief Put string to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts */
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169 extern void uart1_puts(const char *s );
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170 /** @brief Put string from program memory to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts_p */
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171 extern void uart1_puts_p(const char *s );
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172 /** @brief Macro to automatically put a string constant into program memory */
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173 #define uart1_puts_P(__s) uart1_puts_p(PSTR(__s))
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