bicycle_odometer

annotate odometer.c @ 3:c0c68988bcdf

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changed the wheel perimeter
author John Tsiombikas <nuclear@member.fsf.org>
date Thu, 25 Aug 2011 08:22:19 +0300
parents f74f4561e71c
children f883847a0591
rev   line source
nuclear@0 1 /* PORT USAGE
nuclear@0 2 *
nuclear@0 3 * D0-D3: data bus, connected to the D0-D3 pins of all the 4511 chips
nuclear@0 4 * C0-C5,D4,D5: directly driving the 8 speed graph LEDs
nuclear@0 5 * B0-B2: connected to the decoder controlling the 4511 latches as such:
nuclear@0 6 * 000 - speed most significant
nuclear@0 7 * 001 - speed least significant
nuclear@0 8 * 010 - dist most significant
nuclear@0 9 * 011 - dist middle
nuclear@0 10 * 100 - dist least significant
nuclear@0 11 * 101 - all latches are off (high)
nuclear@0 12 * B3-B5: ISP. B4 also acts as generic pushbutton input
nuclear@0 13 * B6,B7: XTAL
nuclear@0 14 * D6,D7: comparator, hall effect sensor input and threshold trimpot.
nuclear@0 15 */
nuclear@0 16
nuclear@0 17 /* 16mhz resonator */
nuclear@2 18 #define F_CPU 16000000
nuclear@0 19
nuclear@0 20 #include <avr/io.h>
nuclear@0 21 #include <avr/interrupt.h>
nuclear@2 22 #include <avr/power.h>
nuclear@0 23 #include <util/delay.h>
nuclear@0 24
nuclear@3 25
nuclear@2 26 #define SEC_TICKS (F_CPU / 256 / 256)
nuclear@2 27
nuclear@2 28 #define PRESCL_1 1
nuclear@2 29 #define PRESCL_8 2
nuclear@2 30 #define PRESCL_64 3
nuclear@2 31 #define PRESCL_256 4
nuclear@2 32 #define PRESCL_1024 5
nuclear@2 33
nuclear@2 34
nuclear@2 35 #define PB_CSEL_MASK 0x7
nuclear@2 36 #define PD_DATA_MASK 0xf
nuclear@2 37 #define PD_LEDS_MASK 0xc0
nuclear@2 38
nuclear@2 39 #define RPS_TO_KMH(x) ((36 * WHEEL_PERIMETER * (x)) / 1000)
nuclear@2 40
nuclear@2 41 #define DEBOUNCE_TICKS 1
nuclear@2 42
nuclear@3 43
nuclear@3 44 /* wheel perimeter in centimeters */
nuclear@3 45 #define WHEEL_PERIMETER 194
nuclear@3 46
nuclear@2 47 #define nop() asm volatile("nop")
nuclear@2 48
nuclear@3 49
nuclear@2 50 void init_timer(void);
nuclear@0 51 void latch(int n);
nuclear@0 52 void update_display(void);
nuclear@2 53 void disp_speed(int n);
nuclear@2 54 void disp_dist(int n);
nuclear@2 55 void disp_leds(int n);
nuclear@0 56
nuclear@0 57 int state;
nuclear@2 58 int debug_mode = 0;
nuclear@2 59
nuclear@2 60 volatile long ticks;
nuclear@0 61
nuclear@0 62 unsigned long nrot;
nuclear@2 63 unsigned long speed_rps;
nuclear@0 64
nuclear@0 65 int main(void)
nuclear@0 66 {
nuclear@0 67 int i;
nuclear@0 68
nuclear@0 69 DDRB = 0xf; /* only first four bits are outputs */
nuclear@0 70 DDRC = 0xff; /* speed leds 6 bits */
nuclear@2 71 DDRD = 0x3f; /* 4bits data bus, 2 bits speed leds, 2 bits comparator (input) */
nuclear@0 72
nuclear@0 73 /* zero-out the displays and disable all pullups except for the reset pin */
nuclear@0 74 PORTB = 0;
nuclear@0 75 PORTC = 0x40; /* 6th bit set, C6 is reset */
nuclear@0 76 PORTD = 0;
nuclear@0 77
nuclear@0 78 for(i=0; i<5; i++) {
nuclear@0 79 latch(i);
nuclear@0 80 }
nuclear@0 81
nuclear@2 82 /* if the button at B4 is pressed during startup, enter debug mode */
nuclear@2 83 if((PINB >> 4) & 1) {
nuclear@2 84 debug_mode = 1;
nuclear@2 85 PORTC |= 3 << 4;
nuclear@2 86 }
nuclear@2 87
nuclear@2 88 init_timer();
nuclear@2 89
nuclear@2 90 /* disable digital input buffer for the AINn pins */
nuclear@2 91 DIDR1 = 0;
nuclear@2 92
nuclear@0 93 /* read initial comparator state */
nuclear@0 94 state = (ACSR >> ACO) & 1;
nuclear@0 95
nuclear@0 96 /* in debug mode we want an interrupt both on rising and falling edge
nuclear@0 97 * to be able to blink leds when the wheel goes past. otherwise we only need
nuclear@0 98 * a rising edge interrupt to increment the rotation counter.
nuclear@0 99 */
nuclear@2 100 /* rising edge interrupt */
nuclear@2 101 /*ACSR |= (2 << ACIS0);*/
nuclear@2 102
nuclear@2 103 /* comparator interrupt enable */
nuclear@2 104 ACSR |= (1 << ACIE);
nuclear@0 105
nuclear@0 106 sei();
nuclear@0 107
nuclear@2 108 for(;;) {
nuclear@2 109 }
nuclear@0 110 return 0;
nuclear@0 111 }
nuclear@0 112
nuclear@2 113 void init_timer(void)
nuclear@2 114 {
nuclear@2 115 power_timer0_enable();
nuclear@2 116
nuclear@2 117 TCCR0A = 0;
nuclear@2 118 TCCR0B = PRESCL_256;
nuclear@2 119
nuclear@2 120 /* enable timer overflow interrupt */
nuclear@2 121 TIMSK0 = 1;
nuclear@2 122 }
nuclear@2 123
nuclear@0 124 void latch(int n)
nuclear@0 125 {
nuclear@2 126 unsigned char upper = PORTB & ~PB_CSEL_MASK;
nuclear@0 127 /* pull latch low */
nuclear@0 128 PORTB = upper | n;
nuclear@0 129 asm volatile("nop");
nuclear@0 130 /* pull all latches high again */
nuclear@0 131 PORTB = upper | 5;
nuclear@0 132 }
nuclear@0 133
nuclear@0 134 ISR(ANALOG_COMP_vect)
nuclear@0 135 {
nuclear@2 136 volatile static long prev_time;
nuclear@2 137 unsigned char aco;
nuclear@2 138
nuclear@2 139 nop();
nuclear@2 140 nop();
nuclear@2 141 nop();
nuclear@2 142
nuclear@2 143 aco = (ACSR >> ACO) & 1;
nuclear@2 144
nuclear@2 145 if(aco != state && (ticks - prev_time) > DEBOUNCE_TICKS) {
nuclear@2 146 state = aco;
nuclear@0 147
nuclear@0 148 if(state) {
nuclear@0 149 nrot++;
nuclear@2 150
nuclear@2 151 update_display();
nuclear@0 152 }
nuclear@0 153 }
nuclear@0 154
nuclear@2 155 prev_time = ticks;
nuclear@2 156 }
nuclear@2 157
nuclear@2 158 ISR(TIMER0_OVF_vect)
nuclear@2 159 {
nuclear@2 160 volatile static int sec_ticks;
nuclear@2 161 volatile static unsigned long last_rot;
nuclear@2 162
nuclear@2 163 ticks++;
nuclear@2 164 sec_ticks++;
nuclear@2 165
nuclear@2 166 if(sec_ticks >= SEC_TICKS) {
nuclear@2 167 speed_rps = nrot - last_rot;
nuclear@2 168
nuclear@2 169 update_display();
nuclear@2 170
nuclear@2 171 sec_ticks = 0;
nuclear@2 172 last_rot = nrot;
nuclear@2 173 }
nuclear@2 174
nuclear@2 175
nuclear@2 176 if(debug_mode) {
nuclear@2 177 unsigned char state = (ACSR >> ACO) & 1;
nuclear@2 178 if(state) {
nuclear@2 179 PORTD |= (1 << 5);
nuclear@2 180 } else {
nuclear@2 181 PORTD &= ~(1 << 5);
nuclear@2 182 }
nuclear@2 183 }
nuclear@0 184 }
nuclear@0 185
nuclear@0 186 void update_display(void)
nuclear@0 187 {
nuclear@2 188 if(debug_mode) {
nuclear@2 189 disp_dist(nrot);
nuclear@2 190 disp_speed(speed_rps);
nuclear@0 191
nuclear@2 192 if(state) {
nuclear@2 193 PORTD |= (1 << 5);
nuclear@2 194 } else {
nuclear@2 195 PORTD &= ~(1 << 5);
nuclear@2 196 }
nuclear@2 197 } else {
nuclear@2 198 unsigned long dist_cm = (nrot * WHEEL_PERIMETER);
nuclear@2 199 int speed_kmh = RPS_TO_KMH(speed_rps);
nuclear@2 200
nuclear@2 201 disp_dist(dist_cm / 10000);
nuclear@2 202 disp_speed(speed_kmh);
nuclear@2 203 disp_leds(speed_kmh * 8);
nuclear@2 204 }
nuclear@0 205 }
nuclear@2 206
nuclear@2 207 void disp_speed(int n)
nuclear@2 208 {
nuclear@2 209 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 210 latch(1);
nuclear@2 211 n /= 10;
nuclear@2 212 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 213 latch(0);
nuclear@2 214 }
nuclear@2 215
nuclear@2 216 void disp_dist(int n)
nuclear@2 217 {
nuclear@2 218 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 219 latch(4);
nuclear@2 220 n /= 10;
nuclear@2 221 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 222 latch(3);
nuclear@2 223 n /= 10;
nuclear@2 224 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 225 latch(2);
nuclear@2 226 }
nuclear@2 227
nuclear@2 228 void disp_leds(int n)
nuclear@2 229 {
nuclear@2 230 int i, count, bits;
nuclear@2 231
nuclear@2 232 count = (n + 4) >> 5;
nuclear@2 233 bits = 0;
nuclear@2 234
nuclear@2 235 for(i=0; i<count; i++) {
nuclear@2 236 bits |= (1 << i);
nuclear@2 237 }
nuclear@2 238
nuclear@2 239 PORTC = bits;
nuclear@2 240 PORTD = (PORTD & PD_DATA_MASK) | ((bits & PD_LEDS_MASK) >> 2);
nuclear@2 241 }