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1702 | - | 1 | // -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*- |
2 | // |
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3 | // Interrupt-driven serial transmit/receive library. |
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4 | // |
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5 | // Copyright (c) 2010 Michael Smith. All rights reserved. |
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6 | // |
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7 | // Receive and baudrate calculations derived from the Arduino |
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8 | // HardwareSerial driver: |
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9 | // |
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10 | // Copyright (c) 2006 Nicholas Zambetti. All right reserved. |
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11 | // |
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12 | // Transmit algorithm inspired by work: |
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13 | // |
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14 | // Code Jose Julio and Jordi Munoz. DIYDrones.com |
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15 | // |
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16 | // This library is free software; you can redistribute it and/or |
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17 | // modify it under the terms of the GNU Lesser General Public |
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18 | // License as published by the Free Software Foundation; either |
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19 | // version 2.1 of the License, or (at your option) any later |
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20 | // version. |
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21 | // |
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22 | // This library is distributed in the hope that it will be |
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23 | // useful, but WITHOUT ANY WARRANTY; without even the implied |
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24 | // warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
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25 | // PURPOSE. See the GNU Lesser General Public License for more |
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26 | // details. |
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27 | // |
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28 | // You should have received a copy of the GNU Lesser General |
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29 | // Public License along with this library; if not, write to the |
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30 | // Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, |
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31 | // Boston, MA 02110-1301 USA |
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32 | // |
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33 | |||
34 | // |
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35 | // Note that this library does not pre-declare drivers for serial |
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36 | // ports; the user must explicitly create drivers for the ports they |
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37 | // wish to use. This is less friendly than the stock Arduino driver, |
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38 | // but it saves a few bytes of RAM for every unused port and frees up |
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39 | // the vector for another driver (e.g. MSPIM on USARTs). |
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40 | // |
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41 | |||
42 | #ifndef FastSerial_h |
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43 | #define FastSerial_h |
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44 | |||
45 | // disable the stock Arduino serial driver |
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46 | #ifdef HardwareSerial_h |
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47 | # error Must include FastSerial.h before the Arduino serial driver is defined. |
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48 | #endif |
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49 | #define HardwareSerial_h |
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50 | |||
51 | #include <inttypes.h> |
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52 | #include <stdlib.h> |
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53 | #include <avr/io.h> |
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54 | #include <avr/interrupt.h> |
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55 | |||
56 | #include "BetterStream.h" |
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57 | |||
58 | |||
59 | /// @file FastSerial.h |
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60 | /// @brief An enhanced version of the Arduino HardwareSerial class |
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61 | /// implementing interrupt-driven transmission and flexible |
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62 | /// buffer management. |
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63 | /// |
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64 | /// Because Arduino libraries aren't really libraries, but we want to |
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65 | /// only define interrupt handlers for serial ports that are actually |
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66 | /// used, we have to force our users to define them using a macro. |
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67 | /// |
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68 | /// FastSerialPort(<port name>, <port number>) |
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69 | /// |
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70 | /// <port name> is the name of the object that will be created by the |
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71 | /// macro. <port number> is the 0-based number of the port that will |
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72 | /// be managed by the object. |
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73 | /// |
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74 | /// Previously ports were defined with a different macro for each port, |
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75 | /// and these macros are retained for compatibility: |
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76 | /// |
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77 | /// FastSerialPort0(<port name>) creates <port name> referencing serial port 0 |
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78 | /// FastSerialPort1(<port name>) creates <port name> referencing serial port 1 |
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79 | /// FastSerialPort2(<port name>) creates <port name> referencing serial port 2 |
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80 | /// FastSerialPort3(<port name>) creates <port name> referencing serial port 3 |
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81 | /// |
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82 | /// Note that compatibility macros are only defined for ports that |
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83 | /// exist on the target device. |
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84 | /// |
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85 | |||
86 | /// @name Compatibility |
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87 | /// |
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88 | /// Forward declarations for clients that want to assume that the |
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89 | /// default Serial* objects exist. |
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90 | /// |
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91 | /// Note that the application is responsible for ensuring that these |
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92 | /// actually get defined, otherwise Arduino will suck in the |
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93 | /// HardwareSerial library and linking will fail. |
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94 | //@{ |
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95 | extern class FastSerial Serial; |
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96 | extern class FastSerial Serial1; |
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97 | extern class FastSerial Serial2; |
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98 | extern class FastSerial Serial3; |
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99 | //@} |
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100 | |||
101 | /// The FastSerial class definition |
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102 | /// |
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103 | class FastSerial: public BetterStream { |
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104 | public: |
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105 | |||
106 | /// Constructor |
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107 | FastSerial(const uint8_t portNumber, volatile uint8_t *ubrrh, volatile uint8_t *ubrrl, volatile uint8_t *ucsra, |
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108 | volatile uint8_t *ucsrb, const uint8_t u2x, const uint8_t portEnableBits, const uint8_t portTxBits); |
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109 | |||
110 | /// @name Serial API |
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111 | //@{ |
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112 | virtual void begin(long baud); |
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113 | virtual void end(void); |
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114 | virtual int available(void); |
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115 | virtual int txspace(void); |
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116 | virtual int read(void); |
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117 | virtual int peek(void); |
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118 | virtual void flush(void); |
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119 | #if defined(ARDUINO) && ARDUINO >= 100 |
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120 | virtual size_t write(uint8_t c); |
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121 | #else |
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122 | virtual void write(uint8_t c); |
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123 | #endif |
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124 | using BetterStream::write; |
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125 | //@} |
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126 | |||
127 | /// Extended port open method |
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128 | /// |
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129 | /// Allows for both opening with specified buffer sizes, and re-opening |
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130 | /// to adjust a subset of the port's settings. |
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131 | /// |
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132 | /// @note Buffer sizes greater than ::_max_buffer_size will be rounded |
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133 | /// down. |
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134 | /// |
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135 | /// @param baud Selects the speed that the port will be |
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136 | /// configured to. If zero, the port speed is left |
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137 | /// unchanged. |
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138 | /// @param rxSpace Sets the receive buffer size for the port. If zero |
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139 | /// then the buffer size is left unchanged if the port |
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140 | /// is open, or set to ::_default_rx_buffer_size if it is |
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141 | /// currently closed. |
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142 | /// @param txSpace Sets the transmit buffer size for the port. If zero |
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143 | /// then the buffer size is left unchanged if the port |
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144 | /// is open, or set to ::_default_tx_buffer_size if it |
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145 | /// is currently closed. |
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146 | /// |
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147 | virtual void begin(long baud, unsigned int rxSpace, unsigned int txSpace); |
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148 | |||
149 | /// Transmit/receive buffer descriptor. |
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150 | /// |
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151 | /// Public so the interrupt handlers can see it |
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152 | struct Buffer { |
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153 | volatile uint16_t head, tail; ///< head and tail pointers |
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154 | uint16_t mask; ///< buffer size mask for pointer wrap |
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155 | uint8_t *bytes; ///< pointer to allocated buffer |
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156 | }; |
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157 | |||
158 | /// Tell if the serial port has been initialized |
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159 | static bool getInitialized(uint8_t port) { |
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160 | return (1<<port) & _serialInitialized; |
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161 | } |
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162 | |||
163 | // ask for writes to be blocking or non-blocking |
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164 | void set_blocking_writes(bool blocking) { |
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165 | _nonblocking_writes = !blocking; |
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166 | } |
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167 | |||
168 | private: |
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169 | |||
170 | /// Bit mask for initialized ports |
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171 | static uint8_t _serialInitialized; |
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172 | |||
173 | /// Set if the serial port has been initialized |
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174 | static void setInitialized(uint8_t port) { |
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175 | _serialInitialized |= (1<<port); |
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176 | } |
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177 | |||
178 | // register accessors |
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179 | volatile uint8_t * const _ubrrh; |
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180 | volatile uint8_t * const _ubrrl; |
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181 | volatile uint8_t * const _ucsra; |
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182 | volatile uint8_t * const _ucsrb; |
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183 | |||
184 | // register magic numbers |
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185 | const uint8_t _u2x; |
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186 | const uint8_t _portEnableBits; ///< rx, tx and rx interrupt enables |
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187 | const uint8_t _portTxBits; ///< tx data and completion interrupt enables |
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188 | |||
189 | |||
190 | // ring buffers |
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191 | Buffer * const _rxBuffer; |
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192 | Buffer * const _txBuffer; |
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193 | bool _open; |
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194 | |||
195 | // whether writes to the port should block waiting |
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196 | // for enough space to appear |
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197 | bool _nonblocking_writes; |
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198 | |||
199 | /// Allocates a buffer of the given size |
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200 | /// |
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201 | /// @param buffer The buffer descriptor for which the buffer will |
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202 | /// will be allocated. |
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203 | /// @param size The desired buffer size. |
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204 | /// @returns True if the buffer was allocated successfully. |
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205 | /// |
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206 | static bool _allocBuffer(Buffer *buffer, unsigned int size); |
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207 | |||
208 | /// Frees the allocated buffer in a descriptor |
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209 | /// |
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210 | /// @param buffer The descriptor whose buffer should be freed. |
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211 | /// |
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212 | static void _freeBuffer(Buffer *buffer); |
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213 | |||
214 | /// default receive buffer size |
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215 | static const unsigned int _default_rx_buffer_size = 128; |
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216 | |||
217 | /// default transmit buffer size |
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218 | static const unsigned int _default_tx_buffer_size = 16; |
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219 | |||
220 | /// maxium tx/rx buffer size |
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221 | /// @note if we could bring the max size down to 256, the mask and head/tail |
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222 | /// pointers in the buffer could become uint8_t. |
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223 | /// |
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224 | static const unsigned int _max_buffer_size = 512; |
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225 | }; |
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226 | |||
227 | // Used by the per-port interrupt vectors |
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228 | extern FastSerial::Buffer __FastSerial__rxBuffer[]; |
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229 | extern FastSerial::Buffer __FastSerial__txBuffer[]; |
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230 | |||
231 | /// Generic Rx/Tx vectors for a serial port - needs to know magic numbers |
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232 | /// |
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233 | #define FastSerialHandler(_PORT, _RXVECTOR, _TXVECTOR, _UDR, _UCSRB, _TXBITS) \ |
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234 | ISR(_RXVECTOR, ISR_BLOCK) \ |
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235 | { \ |
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236 | uint8_t c; \ |
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237 | uint16_t i; \ |
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238 | \ |
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239 | /* read the byte as quickly as possible */ \ |
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240 | c = _UDR; \ |
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241 | /* work out where the head will go next */ \ |
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242 | i = (__FastSerial__rxBuffer[_PORT].head + 1) & __FastSerial__rxBuffer[_PORT].mask; \ |
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243 | /* decide whether we have space for another byte */ \ |
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244 | if (i != __FastSerial__rxBuffer[_PORT].tail) { \ |
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245 | /* we do, move the head */ \ |
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246 | __FastSerial__rxBuffer[_PORT].bytes[__FastSerial__rxBuffer[_PORT].head] = c; \ |
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247 | __FastSerial__rxBuffer[_PORT].head = i; \ |
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248 | } \ |
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249 | } \ |
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250 | ISR(_TXVECTOR, ISR_BLOCK) \ |
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251 | { \ |
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252 | /* if there is another character to send */ \ |
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253 | if (__FastSerial__txBuffer[_PORT].tail != __FastSerial__txBuffer[_PORT].head) { \ |
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254 | _UDR = __FastSerial__txBuffer[_PORT].bytes[__FastSerial__txBuffer[_PORT].tail]; \ |
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255 | /* increment the tail */ \ |
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256 | __FastSerial__txBuffer[_PORT].tail = \ |
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257 | (__FastSerial__txBuffer[_PORT].tail + 1) & __FastSerial__txBuffer[_PORT].mask; \ |
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258 | } else { \ |
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259 | /* there are no more bytes to send, disable the interrupt */ \ |
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260 | if (__FastSerial__txBuffer[_PORT].head == __FastSerial__txBuffer[_PORT].tail) \ |
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261 | _UCSRB &= ~_TXBITS; \ |
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262 | } \ |
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263 | } \ |
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264 | struct hack |
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265 | |||
266 | // |
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267 | // Portability; convert various older sets of defines for U(S)ART0 up |
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268 | // to match the definitions for the 1280 and later devices. |
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269 | // |
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270 | #if !defined(USART0_RX_vect) |
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271 | # if defined(USART_RX_vect) |
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272 | # define USART0_RX_vect USART_RX_vect |
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273 | # define USART0_UDRE_vect USART_UDRE_vect |
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274 | # elif defined(UART0_RX_vect) |
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275 | # define USART0_RX_vect UART0_RX_vect |
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276 | # define USART0_UDRE_vect UART0_UDRE_vect |
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277 | # endif |
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278 | #endif |
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279 | |||
280 | #if !defined(USART1_RX_vect) |
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281 | # if defined(UART1_RX_vect) |
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282 | # define USART1_RX_vect UART1_RX_vect |
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283 | # define USART1_UDRE_vect UART1_UDRE_vect |
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284 | # endif |
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285 | #endif |
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286 | |||
287 | #if !defined(UDR0) |
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288 | # if defined(UDR) |
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289 | # define UDR0 UDR |
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290 | # define UBRR0H UBRRH |
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291 | # define UBRR0L UBRRL |
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292 | # define UCSR0A UCSRA |
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293 | # define UCSR0B UCSRB |
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294 | # define U2X0 U2X |
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295 | # define RXEN0 RXEN |
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296 | # define TXEN0 TXEN |
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297 | # define RXCIE0 RXCIE |
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298 | # define UDRIE0 UDRIE |
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299 | # endif |
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300 | #endif |
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301 | |||
302 | /// |
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303 | /// Macro defining a FastSerial port instance. |
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304 | /// |
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305 | #define FastSerialPort(_name, _num) \ |
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306 | FastSerial _name(_num, \ |
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307 | &UBRR##_num##H, \ |
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308 | &UBRR##_num##L, \ |
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309 | &UCSR##_num##A, \ |
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310 | &UCSR##_num##B, \ |
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311 | U2X##_num, \ |
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312 | (_BV(RXEN##_num) | _BV(TXEN##_num) | _BV(RXCIE##_num)), \ |
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313 | (_BV(UDRIE##_num))); \ |
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314 | FastSerialHandler(_num, \ |
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315 | USART##_num##_RX_vect, \ |
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316 | USART##_num##_UDRE_vect, \ |
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317 | UDR##_num, \ |
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318 | UCSR##_num##B, \ |
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319 | _BV(UDRIE##_num)) |
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320 | |||
321 | /// |
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322 | /// Compatibility macros for previous FastSerial versions. |
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323 | /// |
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324 | /// Note that these are not conditionally defined, as the errors |
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325 | /// generated when using these macros for a board that does not support |
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326 | /// the port are better than the errors generated for a macro that's not |
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327 | /// defined at all. |
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328 | /// |
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329 | #define FastSerialPort0(_portName) FastSerialPort(_portName, 0) |
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330 | #define FastSerialPort1(_portName) FastSerialPort(_portName, 1) |
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331 | #define FastSerialPort2(_portName) FastSerialPort(_portName, 2) |
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332 | #define FastSerialPort3(_portName) FastSerialPort(_portName, 3) |
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333 | |||
334 | #endif // FastSerial_h |