root / branches / autonomous_recharging / code / projects / colonet / testing / dongle / robot_receiver / analog.c @ 1390
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1 | 13 | emarinel | /*
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2 | analog.c - Contains the function implementations for manipulating the ADC
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3 | on the firefly+ board
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4 | |||
5 | author: CMU Robotics Club, Colony Project
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6 | code mostly taken from fwr analog file (author: Tom Lauwers)
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7 | */
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8 | |||
9 | #include <util/delay.h> |
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10 | #include <avr/interrupt.h> |
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11 | #include "analog.h" |
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12 | |||
13 | void analog_init(void){ |
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14 | |||
15 | /*
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16 | ADC Status Register A
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17 | Bit 7 - ADEN is set (enables analog)
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18 | Bit 6 - Start conversion bit is set (must be done once for free-running mode)
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19 | Bit 5 - Enable Auto Trigger (for free running mode)
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20 | Bit 3 - Enable ADC Interrupt (required to run free-running mode)
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21 | Bits 2-0 - Set to create a clock divisor of 128, to make ADC clock = 16,000,000/128
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22 | */
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23 | ADCSRA |= 0xEF;
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24 | |||
25 | /*
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26 | ADMUX register
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27 | Bit 7,6 - Set voltage reference to AVcc (0b01)
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28 | Bit 5 - Set ADLAR bit for left adjust to do simple 8-bit reads
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29 | Bit 4 - X
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30 | Bit 3:0 - Sets the current channel
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31 | */
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32 | ADMUX = 0x67;
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33 | |||
34 | #ifdef FFPP
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35 | DDRA |= 0x70;
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36 | set_adc_mux(0x07);
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37 | #endif
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38 | |||
39 | } |
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40 | |||
41 | #ifdef FFPP
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42 | void set_adc_mux(int which) |
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43 | { |
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44 | // A4..A6 set mux to port 0-7 via binary selection
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45 | |||
46 | // mask so only proper bits are possible.
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47 | which &= 0x07;
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48 | PORTA &= 0x8F;
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49 | PORTA |= which << 4;
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50 | } |
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51 | |||
52 | void enable_analog(int analog_setting) //why do we need this? |
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53 | { |
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54 | // Digital input disable - don't disable any of them
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55 | // Set any of the lower six bits to a 1 to disable that bit
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56 | DDRF = 0x00; //ALL_ANALOG; |
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57 | } |
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58 | #endif
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59 | |||
60 | unsigned int analog8(int which){ |
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61 | |||
62 | #ifdef FFPP
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63 | |||
64 | if(which < EXT_MUX)
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65 | { |
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66 | ADMUX = 0x60 + which;
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67 | } |
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68 | else if(which == EXT_MUX) //Why dont we combine this and the above? |
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69 | { |
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70 | return 0; |
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71 | } |
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72 | else
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73 | { |
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74 | ADMUX = 0x60 + EXT_MUX;
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75 | set_adc_mux(which - 8);
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76 | _delay_ms(10);
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77 | } |
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78 | |||
79 | |||
80 | #else
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81 | ADMUX = 0x60 + which;
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82 | #endif
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83 | |||
84 | _delay_ms(1); // need at least 130 us between conversions (for fwr robot, how much for new avr?) |
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85 | return ADCH;
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86 | } |
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87 | |||
88 | unsigned int analog10(int which){ |
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89 | unsigned int adc_h = 0; |
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90 | unsigned int adc_l = 0; |
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91 | |||
92 | |||
93 | |||
94 | #ifdef FFPP
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95 | |||
96 | if(which < EXT_MUX)
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97 | { |
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98 | ADMUX = 0x60 + which;
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99 | } |
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100 | else if(which == EXT_MUX) //Why dont we combine this and the above? |
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101 | { |
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102 | return 0; |
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103 | } |
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104 | else
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105 | { |
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106 | ADMUX = 0x60 + EXT_MUX;
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107 | set_adc_mux(which - 8);
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108 | _delay_ms(10);
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109 | } |
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110 | |||
111 | |||
112 | #else
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113 | ADMUX = 0x60 + which;
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114 | #endif
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115 | _delay_ms(1);
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116 | adc_l = ADCL; /* highest 2 bits of ADCL -> least 2 bits of analog val */
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117 | adc_h = ADCH; /* ADCH -> 8 highest bits of analog val */
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118 | |||
119 | return (adc_h << 2) | (adc_l >> 6); |
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120 | } |
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121 | |||
122 | int wheel(void){ |
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123 | return analog8(WHEEL_PORT);
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124 | } |
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125 | |||
126 | int battery(void){ |
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127 | return analog8(BATT_PORT) * 500 >>7; /* 5 volts is the max, 255 is the max 8bit number , *2 for the divider */ |
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128 | } |
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129 | |||
130 | SIGNAL (SIG_ADC) |
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131 | { |
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132 | // This is just here to catch ADC interrupts because ADC is free running.
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133 | // No code needs to be in here.
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134 | } |