bicycle_odometer

annotate odometer.c @ 2:f74f4561e71c

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first version almost done
author John Tsiombikas <nuclear@member.fsf.org>
date Wed, 24 Aug 2011 07:51:12 +0300
parents 0c1707508070
children c0c68988bcdf
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@2 25 #define SEC_TICKS (F_CPU / 256 / 256)
nuclear@2 26
nuclear@2 27 #define PRESCL_1 1
nuclear@2 28 #define PRESCL_8 2
nuclear@2 29 #define PRESCL_64 3
nuclear@2 30 #define PRESCL_256 4
nuclear@2 31 #define PRESCL_1024 5
nuclear@2 32
nuclear@2 33
nuclear@2 34 #define PB_CSEL_MASK 0x7
nuclear@2 35 #define PD_DATA_MASK 0xf
nuclear@2 36 #define PD_LEDS_MASK 0xc0
nuclear@2 37
nuclear@2 38 #define RPS_TO_KMH(x) ((36 * WHEEL_PERIMETER * (x)) / 1000)
nuclear@2 39
nuclear@2 40 #define DEBOUNCE_TICKS 1
nuclear@2 41
nuclear@2 42 #define nop() asm volatile("nop")
nuclear@2 43
nuclear@2 44 void init_timer(void);
nuclear@0 45 void latch(int n);
nuclear@0 46 void update_display(void);
nuclear@2 47 void disp_speed(int n);
nuclear@2 48 void disp_dist(int n);
nuclear@2 49 void disp_leds(int n);
nuclear@0 50
nuclear@0 51 int state;
nuclear@2 52 int debug_mode = 0;
nuclear@2 53
nuclear@2 54 volatile long ticks;
nuclear@0 55
nuclear@0 56 unsigned long nrot;
nuclear@2 57 unsigned long speed_rps;
nuclear@0 58
nuclear@0 59 /* wheel perimeter in centimeters */
nuclear@2 60 #define WHEEL_PERIMETER 220
nuclear@0 61
nuclear@0 62 int main(void)
nuclear@0 63 {
nuclear@0 64 int i;
nuclear@0 65
nuclear@0 66 DDRB = 0xf; /* only first four bits are outputs */
nuclear@0 67 DDRC = 0xff; /* speed leds 6 bits */
nuclear@2 68 DDRD = 0x3f; /* 4bits data bus, 2 bits speed leds, 2 bits comparator (input) */
nuclear@0 69
nuclear@0 70 /* zero-out the displays and disable all pullups except for the reset pin */
nuclear@0 71 PORTB = 0;
nuclear@0 72 PORTC = 0x40; /* 6th bit set, C6 is reset */
nuclear@0 73 PORTD = 0;
nuclear@0 74
nuclear@0 75 for(i=0; i<5; i++) {
nuclear@0 76 latch(i);
nuclear@0 77 }
nuclear@0 78
nuclear@2 79 /* if the button at B4 is pressed during startup, enter debug mode */
nuclear@2 80 if((PINB >> 4) & 1) {
nuclear@2 81 debug_mode = 1;
nuclear@2 82 PORTC |= 3 << 4;
nuclear@2 83 }
nuclear@2 84
nuclear@2 85 init_timer();
nuclear@2 86
nuclear@2 87 /* disable digital input buffer for the AINn pins */
nuclear@2 88 DIDR1 = 0;
nuclear@2 89
nuclear@0 90 /* read initial comparator state */
nuclear@0 91 state = (ACSR >> ACO) & 1;
nuclear@0 92
nuclear@0 93 /* in debug mode we want an interrupt both on rising and falling edge
nuclear@0 94 * to be able to blink leds when the wheel goes past. otherwise we only need
nuclear@0 95 * a rising edge interrupt to increment the rotation counter.
nuclear@0 96 */
nuclear@2 97 /* rising edge interrupt */
nuclear@2 98 /*ACSR |= (2 << ACIS0);*/
nuclear@2 99
nuclear@2 100 /* comparator interrupt enable */
nuclear@2 101 ACSR |= (1 << ACIE);
nuclear@0 102
nuclear@0 103 sei();
nuclear@0 104
nuclear@2 105 for(;;) {
nuclear@2 106 }
nuclear@0 107 return 0;
nuclear@0 108 }
nuclear@0 109
nuclear@2 110 void init_timer(void)
nuclear@2 111 {
nuclear@2 112 power_timer0_enable();
nuclear@2 113
nuclear@2 114 TCCR0A = 0;
nuclear@2 115 TCCR0B = PRESCL_256;
nuclear@2 116
nuclear@2 117 /* enable timer overflow interrupt */
nuclear@2 118 TIMSK0 = 1;
nuclear@2 119 }
nuclear@2 120
nuclear@0 121 void latch(int n)
nuclear@0 122 {
nuclear@2 123 unsigned char upper = PORTB & ~PB_CSEL_MASK;
nuclear@0 124 /* pull latch low */
nuclear@0 125 PORTB = upper | n;
nuclear@0 126 asm volatile("nop");
nuclear@0 127 /* pull all latches high again */
nuclear@0 128 PORTB = upper | 5;
nuclear@0 129 }
nuclear@0 130
nuclear@0 131 ISR(ANALOG_COMP_vect)
nuclear@0 132 {
nuclear@2 133 volatile static long prev_time;
nuclear@2 134 unsigned char aco;
nuclear@2 135
nuclear@2 136 nop();
nuclear@2 137 nop();
nuclear@2 138 nop();
nuclear@2 139
nuclear@2 140 aco = (ACSR >> ACO) & 1;
nuclear@2 141
nuclear@2 142 if(aco != state && (ticks - prev_time) > DEBOUNCE_TICKS) {
nuclear@2 143 state = aco;
nuclear@0 144
nuclear@0 145 if(state) {
nuclear@0 146 nrot++;
nuclear@2 147
nuclear@2 148 update_display();
nuclear@0 149 }
nuclear@0 150 }
nuclear@0 151
nuclear@2 152 prev_time = ticks;
nuclear@2 153 }
nuclear@2 154
nuclear@2 155 ISR(TIMER0_OVF_vect)
nuclear@2 156 {
nuclear@2 157 volatile static int sec_ticks;
nuclear@2 158 volatile static unsigned long last_rot;
nuclear@2 159
nuclear@2 160 ticks++;
nuclear@2 161 sec_ticks++;
nuclear@2 162
nuclear@2 163 if(sec_ticks >= SEC_TICKS) {
nuclear@2 164 speed_rps = nrot - last_rot;
nuclear@2 165
nuclear@2 166 update_display();
nuclear@2 167
nuclear@2 168 sec_ticks = 0;
nuclear@2 169 last_rot = nrot;
nuclear@2 170 }
nuclear@2 171
nuclear@2 172
nuclear@2 173 if(debug_mode) {
nuclear@2 174 unsigned char state = (ACSR >> ACO) & 1;
nuclear@2 175 if(state) {
nuclear@2 176 PORTD |= (1 << 5);
nuclear@2 177 } else {
nuclear@2 178 PORTD &= ~(1 << 5);
nuclear@2 179 }
nuclear@2 180 }
nuclear@0 181 }
nuclear@0 182
nuclear@0 183 void update_display(void)
nuclear@0 184 {
nuclear@2 185 if(debug_mode) {
nuclear@2 186 disp_dist(nrot);
nuclear@2 187 disp_speed(speed_rps);
nuclear@0 188
nuclear@2 189 if(state) {
nuclear@2 190 PORTD |= (1 << 5);
nuclear@2 191 } else {
nuclear@2 192 PORTD &= ~(1 << 5);
nuclear@2 193 }
nuclear@2 194 } else {
nuclear@2 195 unsigned long dist_cm = (nrot * WHEEL_PERIMETER);
nuclear@2 196 int speed_kmh = RPS_TO_KMH(speed_rps);
nuclear@2 197
nuclear@2 198 disp_dist(dist_cm / 10000);
nuclear@2 199 disp_speed(speed_kmh);
nuclear@2 200 disp_leds(speed_kmh * 8);
nuclear@2 201 }
nuclear@0 202 }
nuclear@2 203
nuclear@2 204 void disp_speed(int n)
nuclear@2 205 {
nuclear@2 206 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 207 latch(1);
nuclear@2 208 n /= 10;
nuclear@2 209 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 210 latch(0);
nuclear@2 211 }
nuclear@2 212
nuclear@2 213 void disp_dist(int n)
nuclear@2 214 {
nuclear@2 215 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 216 latch(4);
nuclear@2 217 n /= 10;
nuclear@2 218 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 219 latch(3);
nuclear@2 220 n /= 10;
nuclear@2 221 PORTD = (PORTD & ~PD_DATA_MASK) | (n % 10);
nuclear@2 222 latch(2);
nuclear@2 223 }
nuclear@2 224
nuclear@2 225 void disp_leds(int n)
nuclear@2 226 {
nuclear@2 227 int i, count, bits;
nuclear@2 228
nuclear@2 229 count = (n + 4) >> 5;
nuclear@2 230 bits = 0;
nuclear@2 231
nuclear@2 232 for(i=0; i<count; i++) {
nuclear@2 233 bits |= (1 << i);
nuclear@2 234 }
nuclear@2 235
nuclear@2 236 PORTC = bits;
nuclear@2 237 PORTD = (PORTD & PD_DATA_MASK) | ((bits & PD_LEDS_MASK) >> 2);
nuclear@2 238 }