firmware/firmware.c

   1 #include <avr/io.h>
   2 #include <avr/interrupt.h>
   3 #include <util/delay.h>
   4 #include <stdio.h>
   5 #include "clock.h"
   6 #include "modbus.h"
   7
   8 #define ECHO_TIMEOUT            (CLOCK_HZ/10)   // 100 ms
   9 #define MEASUREMENT_WAIT        (2*ECHO_TIMEOUT)
  10 #define MEASUREMENT_SHIFT       0               // running avg (1 << M_SHIFT)
  11
  12 #define N_TRIGGERS 3
  13 #define N_SENSORS 12
  14 #define N_TRIG_SENSORS 4
  15
  16 // static int16_t distances[N_SENSORS];
  17
  18 // hold_regs[0] is unit ID
  19 #define thresholds      (hold_regs+1)
  20 #define led1_sensors    (hold_regs[13])
  21 #define led2_sensors    (hold_regs[14])
  22
  23 #define led_bitmap      (hold_regs[MB_N_HOLD_REGS_EEPROM])
  24 #define distances       (hold_regs+MB_N_HOLD_REGS_EEPROM+1)
  25 #define free_bitmap     (hold_regs[MB_N_HOLD_REGS_EEPROM+13])
  26 #define err_bitmap      (hold_regs[MB_N_HOLD_REGS_EEPROM+14])
  27 #define max_distances   (hold_regs+MB_N_HOLD_REGS_EEPROM+21)
  28
  29 static void pull_trigger(uint8_t trig)
  30 {
  31         switch (trig) {
  32         case 0: PORTD |= _BV(PD7); _delay_us(10); PORTD &= ~_BV(PD7); break;
  33         case 1: PORTB |= _BV(PB4); _delay_us(10); PORTB &= ~_BV(PB4); break;
  34         case 2: PORTC |= _BV(PC4); _delay_us(10); PORTC &= ~_BV(PC4); break;
  35         }
  36 }
  37
  38 static uint16_t get_pin(uint8_t trig)
  39 {
  40         switch (trig) {
  41         case 0: return (PIND & 0x78) >> 3;
  42         case 1: return PINB & 0x0F;
  43         default: return PINC & 0x0F;
  44         }
  45 }
  46
  47 static void do_measurement(unsigned char trig)
  48 {
  49         uint16_t starttimes[N_TRIG_SENSORS], starttime;
  50         uint8_t to_start = (1 << N_TRIG_SENSORS) - 1;
  51         uint8_t to_measure = 0, i;
  52         uint16_t now;
  53
  54         pull_trigger(trig);
  55
  56         starttime = get_clock();
  57
  58         while (to_start || to_measure) {
  59                 uint8_t bits = 0;
  60                 now = get_clock();
  61
  62                 if (now-starttime >= ECHO_TIMEOUT)
  63                         break;
  64
  65                 bits = get_pin(trig);
  66
  67                 for (i = 0; i < N_TRIG_SENSORS; i++) {
  68                         uint8_t mask = 1 << i;
  69
  70                         if ((to_start & mask) && (bits & mask)) {
  71                                 // echo start
  72                                 starttimes[i] = now;
  73                                 to_start &= ~mask;
  74                                 to_measure |= mask;
  75                         } else if ((to_measure & mask) && !(bits & mask)) {
  76 #if MEASUREMENT_SHIFT > 0
  77                                 uint16_t old_d;
  78 #endif
  79                                 uint16_t new_d;
  80                                 uint8_t idx = trig*N_TRIG_SENSORS+i;
  81                                 // echo end
  82                                 to_measure &= ~mask;
  83                                 new_d = now - starttimes[i];
  84                                 if (new_d > max_distances[idx])
  85                                         max_distances[idx] = new_d;
  86
  87 #if MEASUREMENT_SHIFT > 0
  88                                 old_d = distances[idx];
  89
  90                                 if (old_d == 0
  91                                         || old_d == -1) {
  92                                         distances[idx] = new_d;
  93                                 } else {
  94                                         distances[idx] = (
  95                                                 (old_d << MEASUREMENT_SHIFT)
  96                                                 + new_d
  97                                                 - old_d
  98                                                 ) >> MEASUREMENT_SHIFT;
  99                                 }
 100 #else
 101                                 distances[idx] = new_d;
 102 #endif
 103                         }
 104                 }
 105         }
 106
 107         for (i = 0; i < N_TRIG_SENSORS; i++)
 108                 if (to_start & (1 << i))
 109                         distances[trig*N_TRIG_SENSORS + i] = -1;
 110                 else if (to_measure & (1 << i))
 111                         /*
 112                          * If the echo pulse is too long, do not treat it
 113                          * as error, just count it as maximum length.
 114                          */
 115                         distances[trig*N_TRIG_SENSORS + i]
 116                                 = now - starttimes[i];
 117 }
 118
 119 static void led_set(uint8_t led, uint8_t state)
 120 {
 121         if (led == 0) {
 122                 switch (state) {
 123                 case 0:
 124                         led_bitmap &= ~1;
 125                         led_bitmap &= ~2;
 126                         break;
 127                 case 1:
 128                         led_bitmap |= 1;
 129                         led_bitmap &= ~2;
 130                         break;
 131                 default: // error
 132                         led_bitmap |= 2;
 133                         break;
 134                 }
 135         } else {
 136                 switch (state) {
 137                 case 0:
 138                         led_bitmap &= ~4;
 139                         led_bitmap &= ~8;
 140                         break;
 141                 case 1:
 142                         led_bitmap |= 4;
 143                         led_bitmap &= ~8;
 144                         break;
 145                 default:
 146                         led_bitmap |= 8;
 147                         break;
 148                 }
 149         }
 150 }
 151
 152 static void leds_update()
 153 {
 154         if (led_bitmap & 1) {
 155                 PORTC |= _BV(PC5);
 156         } else {
 157                 PORTC &= ~_BV(PC5);
 158         }
 159
 160         if (led_bitmap & 2) {
 161                 DDRC &= ~_BV(PC5);
 162         } else {
 163                 DDRC |= _BV(PC5);
 164         }
 165
 166         if (led_bitmap & 4) {
 167                 PORTB |= _BV(PB5);
 168         } else {
 169                 PORTB &= ~_BV(PB5);
 170         }
 171
 172         if (led_bitmap & 8) {
 173                 DDRB |= _BV(PB5);
 174         } else {
 175                 DDRB &= ~_BV(PB5);
 176         }
 177 }
 178
 179 static void eval_bitmaps()
 180 {
 181         uint16_t free_b = 0, err_b = 0, mask;
 182         uint8_t i;
 183
 184         for (i = 0; i < N_SENSORS; i++) {
 185                 mask = 1 << i;
 186
 187                 if (thresholds[i]) {
 188                         if (distances[i] == -1) {
 189                                 err_b |= mask;
 190                         } else if (distances[i] > thresholds[i]) {
 191                                 free_b |= mask;
 192                         }
 193                 }
 194         }
 195
 196         free_bitmap = free_b;
 197         err_bitmap  = err_b;
 198
 199         if (led1_sensors) {
 200                 if (led1_sensors & err_bitmap) {
 201                         led_set(0, 2);
 202                 } else if (led1_sensors & free_bitmap) {
 203                         led_set(0, 1);
 204                 } else {
 205                         led_set(0, 0);
 206                 }
 207         }
 208
 209         if (led2_sensors) {
 210                 if (led2_sensors & err_bitmap) {
 211                         led_set(1, 2);
 212                 } else if (led2_sensors & free_bitmap) {
 213                         led_set(1, 1);
 214                 } else {
 215                         led_set(1, 0);
 216                 }
 217         }
 218 }
 219
 220 uint8_t hold_reg_is_valid(uint16_t reg, uint16_t val)
 221 {
 222         if (reg == MB_HOLD_REGS_BASE)
 223                 return val > 0 && val <= 247;
 224
 225         return 1;
 226 }
 227
 228 int main()
 229 {
 230         modbus_init(0);
 231
 232         // output pins
 233         DDRD |= _BV(PD7); // Trig D
 234         DDRB |= _BV(PB4) | _BV(PB5); // Trig B, LED 2
 235         DDRC |= _BV(PC4) | _BV(PC5); // Trig C, LED 1
 236
 237         // set up the timer
 238         TCCR1A = 0;
 239         TCCR1B = _BV(CS12)|_BV(CS10); // CLK/1024
 240
 241         // enable interrupts
 242         sei();
 243
 244         while(1) {
 245                 uint8_t trig;
 246                 for (trig = 0; trig < N_TRIGGERS; trig++) {
 247                         uint16_t now;
 248                         do_measurement(trig);
 249                         now = get_clock();
 250                         while (get_clock()-now < MEASUREMENT_WAIT)
 251                                 modbus_poll();
 252                 }
 253
 254                 eval_bitmaps();
 255                 leds_update(); // might be written from modbus
 256 //              led_set(0,
 257 //                      distances[4] > 100 || distances[11] > 100);
 258         }
 259 }
 260