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1053 | - | 1 | #ifndef UART_H |
2 | #define UART_H |
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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 1.8.2.1 2007/07/01 11:14:38 peter Exp $ |
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7 | Software: AVR-GCC 4.1, AVR Libc 1.4 |
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8 | Hardware: any AVR with built-in UART, tested on AT90S8515 & ATmega8 at 4 Mhz |
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9 | License: GNU General Public License |
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10 | Usage: see Doxygen manual |
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11 | |||
12 | LICENSE: |
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13 | Copyright (C) 2006 Peter Fleury |
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14 | |||
15 | This program is free software; you can redistribute it and/or modify |
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16 | it under the terms of the GNU General Public License as published by |
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17 | the Free Software Foundation; either version 2 of the License, or |
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18 | any later version. |
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19 | |||
20 | This program is distributed in the hope that it will be useful, |
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21 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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22 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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23 | GNU General Public License for more details. |
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24 | |||
25 | ************************************************************************/ |
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26 | |||
27 | /** |
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28 | * @defgroup pfleury_uart UART Library |
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29 | * @code #include <uart.h> @endcode |
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30 | * |
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31 | * @brief Interrupt UART library using the built-in UART with transmit and receive circular buffers. |
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32 | * |
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33 | * This library can be used to transmit and receive data through the built in UART. |
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34 | * |
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35 | * An interrupt is generated when the UART has finished transmitting or |
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36 | * receiving a byte. The interrupt handling routines use circular buffers |
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37 | * for buffering received and transmitted data. |
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38 | * |
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39 | * The UART_RX_BUFFER_SIZE and UART_TX_BUFFER_SIZE constants define |
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40 | * the size of the circular buffers in bytes. Note that these constants must be a power of 2. |
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41 | * You may need to adapt this constants to your target and your application by adding |
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42 | * CDEFS += -DUART_RX_BUFFER_SIZE=nn -DUART_RX_BUFFER_SIZE=nn to your Makefile. |
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43 | * |
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44 | * @note Based on Atmel Application Note AVR306 |
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45 | * @author Peter Fleury pfleury@gmx.ch http://jump.to/fleury |
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46 | */ |
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47 | |||
48 | /**@{*/ |
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49 | |||
50 | |||
51 | #if (__GNUC__ * 100 + __GNUC_MINOR__) < 304 |
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52 | #error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !" |
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53 | #endif |
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54 | |||
55 | |||
56 | /* |
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57 | ** constants and macros |
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58 | */ |
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59 | |||
60 | /** @brief UART Baudrate Expression |
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61 | * @param xtalcpu system clock in Mhz, e.g. 4000000L for 4Mhz |
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62 | * @param baudrate baudrate in bps, e.g. 1200, 2400, 9600 |
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63 | */ |
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64 | #define UART_BAUD_SELECT(baudRate,xtalCpu) ((xtalCpu)/((baudRate)*16l)-1) |
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65 | |||
66 | /** @brief UART Baudrate Expression for ATmega double speed mode |
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67 | * @param xtalcpu system clock in Mhz, e.g. 4000000L for 4Mhz |
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68 | * @param baudrate baudrate in bps, e.g. 1200, 2400, 9600 |
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69 | */ |
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70 | #define UART_BAUD_SELECT_DOUBLE_SPEED(baudRate,xtalCpu) (((xtalCpu)/((baudRate)*8l)-1)|0x8000) |
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71 | |||
72 | |||
73 | /** Size of the circular receive buffer, must be power of 2 */ |
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74 | #ifndef UART_RX_BUFFER_SIZE |
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75 | #define UART_RX_BUFFER_SIZE 32 |
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76 | #endif |
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77 | /** Size of the circular transmit buffer, must be power of 2 */ |
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78 | #ifndef UART_TX_BUFFER_SIZE |
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79 | #define UART_TX_BUFFER_SIZE 32 |
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80 | #endif |
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81 | |||
82 | /* test if the size of the circular buffers fits into SRAM */ |
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83 | #if ( (UART_RX_BUFFER_SIZE+UART_TX_BUFFER_SIZE) >= (RAMEND-0x60 ) ) |
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84 | #error "size of UART_RX_BUFFER_SIZE + UART_TX_BUFFER_SIZE larger than size of SRAM" |
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85 | #endif |
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86 | |||
87 | /* |
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88 | ** high byte error return code of uart_getc() |
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89 | */ |
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90 | #define UART_FRAME_ERROR 0x0800 /* Framing Error by UART */ |
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91 | #define UART_OVERRUN_ERROR 0x0400 /* Overrun condition by UART */ |
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92 | #define UART_BUFFER_OVERFLOW 0x0200 /* receive ringbuffer overflow */ |
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93 | #define UART_NO_DATA 0x0100 /* no receive data available */ |
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94 | |||
95 | |||
96 | /* |
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97 | ** function prototypes |
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98 | */ |
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99 | |||
100 | /** |
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101 | @brief Initialize UART and set baudrate |
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102 | @param baudrate Specify baudrate using macro UART_BAUD_SELECT() |
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103 | @return none |
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104 | */ |
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105 | extern void uart_init(unsigned int baudrate); |
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106 | |||
107 | |||
108 | /** |
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109 | * @brief Get received byte from ringbuffer |
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110 | * |
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111 | * Returns in the lower byte the received character and in the |
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112 | * higher byte the last receive error. |
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113 | * UART_NO_DATA is returned when no data is available. |
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114 | * |
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115 | * @param void |
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116 | * @return lower byte: received byte from ringbuffer |
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117 | * @return higher byte: last receive status |
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118 | * - \b 0 successfully received data from UART |
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119 | * - \b UART_NO_DATA |
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120 | * <br>no receive data available |
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121 | * - \b UART_BUFFER_OVERFLOW |
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122 | * <br>Receive ringbuffer overflow. |
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123 | * We are not reading the receive buffer fast enough, |
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124 | * one or more received character have been dropped |
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125 | * - \b UART_OVERRUN_ERROR |
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126 | * <br>Overrun condition by UART. |
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127 | * A character already present in the UART UDR register was |
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128 | * not read by the interrupt handler before the next character arrived, |
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129 | * one or more received characters have been dropped. |
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130 | * - \b UART_FRAME_ERROR |
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131 | * <br>Framing Error by UART |
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132 | */ |
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133 | extern unsigned int uart_getc(void); |
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134 | |||
135 | |||
136 | /** |
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137 | * @brief Put byte to ringbuffer for transmitting via UART |
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138 | * @param data byte to be transmitted |
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139 | * @return none |
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140 | */ |
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141 | |||
142 | |||
143 | |||
144 | |||
145 | /** @brief Initialize USART1 (only available on selected ATmegas) @see uart_init */ |
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146 | extern void uart1_init(unsigned int baudrate); |
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147 | /** @brief Get received byte of USART1 from ringbuffer. (only available on selected ATmega) @see uart_getc */ |
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148 | extern unsigned int uart1_getc(void); |
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149 | /** @brief Put byte to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_putc */ |
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150 | extern void uart1_putc(unsigned char data); |
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151 | /** @brief Put string to ringbuffer for transmitting via USART1 (only available on selected ATmega) @see uart_puts */ |
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152 | extern void uart1_puts(const char *s ); |
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153 | /** @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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154 | extern void uart1_puts_p(const char *s ); |
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155 | /** @brief Macro to automatically put a string constant into program memory */ |
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156 | #define uart1_puts_P(__s) uart1_puts_p(PSTR(__s)) |
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157 | |||
158 | /**@}*/ |
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159 | |||
160 | |||
161 | #endif // UART_H |
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162 |