1 | #include <avr/io.h>
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2 | #include <avr/interrupt.h>
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3 | #include <util/delay.h>
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4 | #include <string.h>
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5 | #include <stdlib.h>
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6 |
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7 |
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8 | #define BAUD 9600
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9 |
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10 |
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11 | #define MYUBRR ((uint16_t) ((F_CPU / ((BAUD) * 16.0)) + .5) - 1)
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12 | #define LED1 PD6
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13 | #define LED2 PD7
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14 |
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15 |
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16 |
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17 | // contains what the bluetooth module received
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18 | uint8_t data;
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19 |
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20 |
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21 | void USART_Init(unsigned int ubrr) {
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22 | // set baud rate
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23 | UBRRH = (unsigned char)(ubrr>>8);
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24 | UBRRL = (unsigned char)(ubrr);
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25 | // enable receiver, transmitter and interrupts for rx/tx
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26 | //UCSRB = (1<<RXEN) | (1<<TXEN) | (1<<RXCIE) | (1<< TXCIE);
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27 | UCSRB = (1<<TXEN);
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28 |
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29 | // frame format: 8 bits data, 1 stop bit, no parity - these are the default settings for atmega168.
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30 | // no change needed
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31 | // could be changed here: //(0<<UPM00) not tested
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32 | // UCSR0C = (1<<UCSZ00) | (1<<UCSZ01) | (0<<UPM00) | (0<<UPM01);
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33 | }
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34 |
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35 |
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36 |
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37 | void USART_transmit(char c) {
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38 | // the commented out test if we are ready to send should work too
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39 | //while ((UCSR0A & (1 << UDRE0)) == 0) {};
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40 | while ( !(UCSRA & (1<<UDRE)) ) {}
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41 | UDR = c;
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42 | }
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43 |
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44 |
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45 |
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46 |
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47 | void send_string(char s[]) {
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48 | int i =0;
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49 |
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50 | while (s[i] != 0x00) {
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51 | USART_transmit(s[i]);
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52 | i++;
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53 | }
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54 | USART_transmit('\r');
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55 | USART_transmit('\n');
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56 |
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57 | }
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58 |
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59 |
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60 |
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61 |
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62 | void InitADC(void) {
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63 | // Select Vref=AVcc
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64 | ADMUX |= ( 1 << REFS0);
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65 |
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66 | // old, clumsy code...to much at once
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67 | //ADCSRA |= (1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0)|(1<<ADEN);
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68 |
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69 | // ADEN = Enable ADC
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70 | ADCSRA=(1<<ADEN);
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71 |
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72 | // prescalar FCPU/128 = 16000000 / 128 = 125khz
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73 | ADCSRA=(1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0);
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74 | }
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75 |
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76 |
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77 | uint16_t readADC(uint8_t ADCchannel) {
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78 |
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79 | // This is the code that selects the channel. AND out the entire mux area,
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80 | // then OR in the desired analog channel.
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81 | ADMUX &= ~((1<<MUX3) | (1<<MUX2) | (1<<MUX1) | (1<<MUX0));
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82 | ADMUX |= ADCchannel;
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83 |
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84 | //ADMUX |= 0xb00000000;
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85 |
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86 | // single conversion mode
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87 | ADCSRA |= (1<<ADSC);
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88 |
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89 | // ...if you block on ADSC rather than ADIF (wait while it's high rather than low) then it self clears (goes back to 0) so you don't need to manually clear it.
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90 | // Wait for conversion to complete
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91 | while(ADCSRA & (1<<ADSC));
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92 |
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93 | // second conversion, the first maybe off
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94 | ADCSRA |= (1<<ADSC);
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95 |
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96 | while(ADCSRA & (1<<ADSC));
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97 |
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98 |
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99 |
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100 | return(ADC);
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101 | }
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102 |
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103 |
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104 |
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105 |
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106 |
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107 |
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108 |
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109 | int main(void) {
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110 | unsigned int adc_value;
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111 | InitADC();
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112 |
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113 |
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114 | DDRD |= (1 << LED1);
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115 | DDRD |= (1 << LED2);
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116 | // led test
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117 | PORTD |= (1 << LED1); // Turn on LED1
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118 | _delay_ms(1000);
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119 | PORTD &= ~(1 << LED1); // Turn off LED1
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120 |
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121 |
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122 | // this gives a buffer overflow, the range 0...1023 does not fit into 3
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123 | //char output[3];
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124 |
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125 | char output[7];
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126 |
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127 | USART_Init(MYUBRR);
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128 |
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129 | sei();
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130 |
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131 | while(1){
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132 | adc_value = readADC(0);
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133 |
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134 | if (adc_value > 10) {
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135 | PORTD |= (1 << LED2); // Turn on LED1
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136 | _delay_ms(1000);
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137 | PORTD &= ~(1 << LED2); // Turn off LED1
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138 | }
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139 |
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140 |
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141 |
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142 | // !!!
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143 | // use stdoul as replacement for itoa
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144 | // convert integer to string
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145 | itoa(adc_value, output, 10);
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146 |
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147 | // send value via bluetooth
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148 | send_string(output);
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149 |
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150 | // (I KNOW; _delay_ms is bad) wait for the next conversion, 3 seconds
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151 | _delay_ms(3000);
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152 |
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153 | // show some activity to know that the chip didnt hang
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154 | PORTD |= (1 << LED1); // Turn on LED1
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155 | _delay_ms(1000);
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156 | PORTD &= ~(1 << LED1); // Turn off LED1
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157 |
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158 | }
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159 | }
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