1 | */ RINGPUFFER: circbuf.h */
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2 | #ifndef CIRCBUF_H_
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3 | #define CIRCBUF_H_
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4 |
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5 | #include <stdbool.h>
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6 | #include <avr/io.h>
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7 | #include <stdlib.h>
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8 | #include <avr/interrupt.h>
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9 |
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10 |
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11 | #define buffer_size 16
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12 |
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13 | struct circ_buffer {
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14 | uint8_t data[buffer_size];
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15 | uint8_t read_ptr; // points to last input data
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16 | uint8_t write_ptr; // always points to empty field
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17 | };
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18 |
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19 | void buffer_init (struct circ_buffer *buf);
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20 | void buffer_write(struct circ_buffer *buf, uint8_t byte);
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21 | uint8_t buffer_read(struct circ_buffer *buf);
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22 | uint8_t buffer_is_full (struct circ_buffer *buf);
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23 | uint8_t buffer_is_empty (struct circ_buffer *buf);
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24 |
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25 | #endif /*CIRCBUF_H_*/
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26 | /* END circbuf.h */
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27 |
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28 |
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29 | /* RINGPUFFER FUNCTIONS circbuf.c*/
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30 | #include "circbuf.h"
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31 |
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32 | void buffer_init (struct circ_buffer *buf) // Initialization of circular buffer values
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33 | {
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34 | buf->read_ptr=0;
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35 | buf->write_ptr=0;
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36 | }
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37 |
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38 | void buffer_write(struct circ_buffer *buf, uint8_t byte) // Write byte into buffer, increment fillcounter and write pointer
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39 | {
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40 | cli();
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41 | buf->data[buf->write_ptr] = byte;
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42 |
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43 | if (buf->write_ptr >= buffer_size-1){
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44 | buf->write_ptr = 0;
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45 | }
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46 | else{
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47 | buf->write_ptr = buf->write_ptr + 1;
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48 | }
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49 | sei();
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50 | }
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51 |
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52 | uint8_t buffer_read(struct circ_buffer *buf) // Read byte out of buffer, decrement fillcounter, increment read ptr
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53 | {
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54 | cli();
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55 | uint8_t returnval =0;
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56 |
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57 | if (buf->read_ptr == buf->write_ptr){
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58 | sei();
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59 | return 0;
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60 | }
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61 | else
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62 | {
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63 | returnval= buf->data[buf->read_ptr];
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64 |
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65 | if (buf->read_ptr >= buffer_size-1){
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66 | buf->read_ptr = 0;
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67 | }
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68 | else{
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69 | buf->read_ptr = buf->read_ptr + 1;
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70 | }
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71 | sei();
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72 | return returnval;
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73 | }
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74 |
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75 | }
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76 |
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77 | uint8_t buffer_is_full (struct circ_buffer *buf)
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78 | {
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79 | if (buf->write_ptr + 1 == buf->read_ptr || buf->read_ptr == 0 && buf->write_ptr + 1 == buffer_size)
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80 | return 1;
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81 | else return 0;
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82 | }
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83 |
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84 | uint8_t buffer_is_empty (struct circ_buffer *buf)
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85 | {
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86 | if (buf->read_ptr == buf->write_ptr) return 1;
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87 | else return 0;
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88 | }
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89 |
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90 | /* END RINGPUFFER FUNCTIONS circbuf.c */
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91 |
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92 |
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93 |
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94 | /* UART_functions.h */
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95 |
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96 | #ifndef _M_UART_functions_h_
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97 | #define _M_UART_functions_h_
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98 |
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99 | #define F_CPU 20E6 //Systemtakt in Hz
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100 | #include <util/delay.h>
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101 |
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102 | #include "circbuf.h"
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103 |
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104 | // FUNCTIONS
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105 | void UART_Init();
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106 | uint8_t uart_ReceiveByte( struct circ_buffer *buf );
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107 | void uart_TransmitByte( struct circ_buffer *buf, uint8_t data );
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108 |
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109 | #endif /*_M_UART_functions_h_*/
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110 |
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111 | /* END UART_functions.h */
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112 |
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113 |
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114 | /* UART_functions.c */
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115 |
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116 | #include <avr/io.h>
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117 | #include <avr/interrupt.h>
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118 | #include <stdlib.h>
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119 |
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120 | #include "UART_functions.h"
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121 | #include <util/delay.h>
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122 |
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123 |
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124 | void UART_Init()
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125 | {
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126 | // baud Calculation: baud = (fosc/ 16*Baudrate)-0.5
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127 | // baud = (20 MHz / 16*9600)-0.5 = 129.708 --> = baud = 130
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128 | unsigned int baud = 130;
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129 |
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130 | //* Set baud rate */
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131 | UBRR0H = (unsigned char)(baud>>8);
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132 | UBRR0L = (unsigned char)baud;
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133 | /* Enable receiver and transmitter, Set Interrupts: RXCIE - RX-Complete */
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134 | UCSR0B = (1<<RXEN0)|(1<<TXEN0)|(1<<RXCIE0);
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135 | /* Set frame format: 8data, 2stop bit */
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136 | UCSR0C = (1<<USBS0)|(3<<UCSZ00);
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137 | }
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138 |
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139 | uint8_t uart_ReceiveByte( struct circ_buffer *buf )
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140 | {
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141 | while ( buffer_is_empty(buf) ); /* wait for incoming data */
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142 | return buffer_read(buf); /* return data */
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143 | }
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144 |
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145 |
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146 | void uart_TransmitByte(struct circ_buffer *buf, uint8_t data )
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147 | {
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148 | while ( buffer_is_full(buf) );
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149 | buffer_write(buf,data); /* store data in buffer */
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150 |
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151 | UCSR0B |= (1<<UDRIE0); // Enable UDRIE- UART Data Register empty Interrupt - UDRE-ISR is going to put data in UDR
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152 | }
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153 |
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154 | /* END UART_functions.c */
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155 |
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156 |
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157 | /* MAIN.c */
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158 |
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159 | #include <avr/io.h>
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160 | #include <avr/interrupt.h>
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161 | #include <stdlib.h>
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162 | #include "stdbool.h"
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163 | #include <string.h>
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164 |
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165 | #define F_CPU 20E6 //Systemtakt in Hz
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166 |
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167 | #include "UART_functions.h"
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168 | #include "circbuf.h"
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169 | #include <util/delay.h>
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170 |
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171 | // Global VARIABLES
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172 | unsigned char byte_buffer;
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173 | struct circ_buffer uart_rx_buffer; // Receive-Circular-Buffer
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174 | struct circ_buffer uart_tx_buffer; // Send-Circular-Buffer
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175 |
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176 |
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177 | // UART RX-Complete interrupt:
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178 | // Receiving data + buffering (saving)
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179 | ISR(USART0_RX_vect)
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180 | {
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181 | unsigned char data;
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182 | data = UDR0;
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183 | buffer_write(&uart_rx_buffer, data);
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184 | }
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185 |
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186 | // UART Data register empty interrupt:
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187 | // loading new data into UART sending register
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188 | ISR(USART0_UDRE_vect)
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189 | {
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190 | if (!buffer_is_empty(&uart_tx_buffer)) // Is buffer filled?
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191 | {
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192 | UDR0 = buffer_read(&uart_tx_buffer);
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193 | }
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194 | else
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195 | {
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196 | UCSR0B &= ~(1<<UDRIE0); // Disable UDRIE- UART Data Register empty Interrupt
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197 | }
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198 | }
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199 |
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200 | int main(void)
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201 | {
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202 | /* Buffer Initialization */
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203 | buffer_init(&uart_rx_buffer);
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204 | buffer_init(&uart_tx_buffer);
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205 |
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206 | /* Variables */
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207 | char controlbyte;
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208 | uint8_t sendbuffer;
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209 | uint32_t adcrec;
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210 |
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211 | /*********************** Initialization ***********************/
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212 | //Port Directions
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213 |
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214 | DDRA= 0b11011011;
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215 | DDRB= 0b10100110;
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216 | DDRC= 0b01010001; // SPI Slave select, LEDs
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217 | DDRD= 0b00001010; // UART
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218 |
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219 | UART_Init(); // UART initialization
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220 | sei(); // Global Interrupt enable
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221 |
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222 | /*********** MAIN LOOP **************/
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223 | while(1)
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224 | {
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225 |
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226 | if (!buffer_is_empty(&uart_rx_buffer)) // Received Commands?
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227 | {
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228 | controlbyte = uart_ReceiveByte(&uart_rx_buffer);
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229 |
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230 | switch (controlbyte)
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231 | {
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232 | case 0xAA: {
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233 | sendbuffer =00;
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234 | uart_TransmitByte(&uart_tx_buffer, sendbuffer);
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235 |
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236 | adcrec = 0xFFABCDEF;
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237 |
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238 | sendbuffer =(adcrec >>24);
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239 | uart_TransmitByte(&uart_tx_buffer, sendbuffer);
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240 | sendbuffer =(adcrec >>16);
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241 | uart_TransmitByte(&uart_tx_buffer, sendbuffer);
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242 | sendbuffer =(adcrec >>8);
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243 | uart_TransmitByte(&uart_tx_buffer, sendbuffer);
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244 | sendbuffer =adcrec;
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245 | uart_TransmitByte(&uart_tx_buffer, sendbuffer);
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246 | sendbuffer =00;
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247 | uart_TransmitByte(&uart_tx_buffer, sendbuffer);
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248 | break;
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249 | }
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250 | case 0xBB: {
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251 | break;
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252 | }
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253 | case 0xCC:{
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254 | break;
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255 | }
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256 | }
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257 | }
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258 | }
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259 | }
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260 |
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261 | /* END MAIN.C */
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