1 |
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2 | /**
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3 | * ADCdisplay displays the value of the adc :-)
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4 | * version 2 - uses ISR
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5 | *
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6 | * Outupt on a 2x16 LCD:
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7 | * ----------------
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8 | * ADC-Value
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9 | * -> 223/222/224
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10 | * ----------------
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11 | * which is -> current / min / max
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12 | *
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13 | */
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14 |
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15 | #define F_CPU 16000000UL // Clock speed
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16 |
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17 | #define LED_RED 0b00000001 // PIN Register for the red led
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18 | #define LED_GREEN 0b00000010 // PIN Register for the green led
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19 |
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20 | #include <stdlib.h>
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21 | #include <avr/io.h>
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22 | #include <avr/interrupt.h>
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23 | #include <util/delay.h>
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24 | #include "lcd.h"
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25 |
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26 | volatile int value = 0; // current value
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27 | int last_value = 0; // value from the last messurement
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28 | int biggest = 0; // max value
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29 | int lowest = 1023; // min value
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30 |
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31 | char buf[4]; // a buffer for the value to disply
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32 |
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33 | /**
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34 | * On the dev-board there are two
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35 | * static led's a red one and a
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36 | * green one.
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37 | * This routine flashes one off
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38 | * the static leds.
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39 | * ---------------------------- //
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40 | *
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41 | */
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42 | void blink_led(int led){ // toggle a PIN on PortB for any blink call
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43 | PORTB |= led; // LED on
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44 | _delay_ms(150);
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45 | PORTB &= ~led; // toggle LED off
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46 | _delay_ms(300);
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47 | return;
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48 | }
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49 |
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50 | /**
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51 | * Interupt calld by change in
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52 | * ADC register
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53 | * ---------------------------- //
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54 | *
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55 | */
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56 | ISR(ADC_vect)
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57 | {
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58 | blink_led(LED_GREEN); // tell that the conversation is done
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59 | value = ADCW;
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60 | }
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61 |
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62 | /**
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63 | * Enable and configure
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64 | * the analog-digital converter
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65 | * ---------------------------- //
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66 | *
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67 | */
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68 | void initADC(channel){
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69 |
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70 | TCNT0=0x00; // set timer.0 to initial 0
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71 | TCCR0B = (1<<CS02); // start timer0 with /256 prescaler
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72 |
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73 | ADCSRA = (1<<ADEN) // enable ADC
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74 | | (1<<ADIE) // enable interupt
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75 | | (1<<ADATE)
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76 | | (1<<ADPS2) // set 128 to the prescaller
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77 | | (1<<ADPS1)
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78 | | (1<<ADPS0);
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79 |
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80 | ADCSRB = ((1<<ADTS2) // set timer.0 overflow
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81 | | (0<<ADTS1)
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82 | | (0<<ADTS0));
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83 |
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84 | ADMUX = channel | (1<<REFS0); // set the channel
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85 |
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86 | }
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87 |
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88 | /**
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89 | * Main routine
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90 | * ---------------------------- //
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91 | *
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92 | */
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93 | int main(void){
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94 | DDRB = 0b00000011; // set up pin direction PortB as Output
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95 | blink_led(LED_RED);
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96 |
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97 | lcd_init(LCD_DISP_ON); // initialize display, cursor off
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98 |
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99 | lcd_puts("*** WELCOME ***\n"); // welcome message
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100 | lcd_puts(" - ADCV V.2 - ");
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101 | _delay_ms(2000); // wait for 2sec
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102 |
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103 | lcd_clrscr(); // clear display and home cursor
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104 | lcd_puts("ADC-Value\n"); // show the mode
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105 | lcd_puts("->"); // show the indicator
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106 |
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107 |
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108 | initADC(5);
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109 |
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110 | sei();
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111 | while(1) { // Mainloop
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112 | blink_led(LED_RED);
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113 |
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114 | if(value != last_value){ // if something has changes
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115 |
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116 | itoa(value, buf, 10); // convert the int to string buffer
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117 |
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118 | lcd_home(); // display cleanup
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119 | lcd_gotoxy(2,1);
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120 | lcd_puts(" ");
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121 | lcd_home();
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122 | lcd_gotoxy(2,1);
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123 | lcd_puts(buf); // show current value
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124 |
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125 | if(value > biggest){ // get min and max
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126 | biggest = value;
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127 | }
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128 | if(value < lowest){
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129 | lowest = value;
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130 | }
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131 |
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132 | lcd_puts("/");
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133 | itoa(lowest, buf, 10);
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134 | lcd_puts(buf); // show min
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135 |
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136 | lcd_puts("/");
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137 | itoa(biggest, buf, 10);
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138 | lcd_puts(buf); // show max
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139 |
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140 | last_value = value; // remember the last value
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141 |
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142 | }
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143 | }
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144 | }
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