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
  53         pull_trigger(trig);
  54
  55         starttime = get_clock();
  56
  57         while (to_start || to_measure) {
  58                 uint8_t bits = 0;
  59                 uint16_t now = get_clock();
  60
  61                 if (now-starttime >= ECHO_TIMEOUT)
  62                         break;
  63
  64                 bits = get_pin(trig);
  65
  66                 for (i = 0; i < N_TRIG_SENSORS; i++) {
  67                         uint8_t mask = 1 << i;
  68
  69                         if ((to_start & mask) && (bits & mask)) {
  70                                 // echo start
  71                                 starttimes[i] = now;
  72                                 to_start &= ~mask;
  73                                 to_measure |= mask;
  74                         } else if ((to_measure & mask) && !(bits & mask)) {
  75 #if MEASUREMENT_SHIFT > 0
  76                                 uint16_t old_d;
  77 #endif
  78                                 uint16_t new_d;
  79                                 uint8_t idx = trig*N_TRIG_SENSORS+i;
  80                                 // echo end
  81                                 to_measure &= ~mask;
  82                                 new_d = now - starttimes[i];
  83                                 if (new_d > max_distances[idx])
  84                                         max_distances[idx] = new_d;
  85
  86 #if MEASUREMENT_SHIFT > 0
  87                                 old_d = distances[idx];
  88
  89                                 if (old_d == 0
  90                                         || old_d == -1) {
  91                                         distances[idx] = new_d;
  92                                 } else {
  93                                         distances[idx] = (
  94                                                 (old_d << MEASUREMENT_SHIFT)
  95                                                 + new_d
  96                                                 - old_d
  97                                                 ) >> MEASUREMENT_SHIFT;
  98                                 }
  99 #else
 100                                 distances[idx] = new_d;
 101 #endif
 102                         }
 103                 }
 104         }
 105
 106         for (i = 0; i < N_TRIG_SENSORS; i++)
 107                 if (to_start & (1 << i))
 108                         distances[trig*N_TRIG_SENSORS + i] = -1;
 109                 else if (to_measure & (1 << i))
 110                         distances[trig*N_TRIG_SENSORS + i] = 0;
 111 }
 112
 113 static void led_set(uint8_t led, uint8_t state)
 114 {
 115         if (led == 0) {
 116                 switch (state) {
 117                 case 0:
 118                         led_bitmap &= ~1;
 119                         led_bitmap &= ~2;
 120                         break;
 121                 case 1:
 122                         led_bitmap |= 1;
 123                         led_bitmap &= ~2;
 124                         break;
 125                 default: // error
 126                         led_bitmap |= 2;
 127                         break;
 128                 }
 129         } else {
 130                 switch (state) {
 131                 case 0:
 132                         led_bitmap &= ~4;
 133                         led_bitmap &= ~8;
 134                         break;
 135                 case 1:
 136                         led_bitmap |= 4;
 137                         led_bitmap &= ~8;
 138                         break;
 139                 default:
 140                         led_bitmap |= 8;
 141                         break;
 142                 }
 143         }
 144 }
 145
 146 static void leds_update()
 147 {
 148         if (led_bitmap & 1) {
 149                 PORTC |= _BV(PC5);
 150         } else {
 151                 PORTC &= ~_BV(PC5);
 152         }
 153
 154         if (led_bitmap & 2) {
 155                 DDRC &= ~_BV(PC5);
 156         } else {
 157                 DDRC |= _BV(PC5);
 158         }
 159
 160         if (led_bitmap & 4) {
 161                 PORTB |= _BV(PB5);
 162         } else {
 163                 PORTB &= ~_BV(PB5);
 164         }
 165
 166         if (led_bitmap & 8) {
 167                 DDRB |= _BV(PB5);
 168         } else {
 169                 DDRB &= ~_BV(PB5);
 170         }
 171 }
 172
 173 static void eval_bitmaps()
 174 {
 175         uint16_t free_b = 0, err_b = 0, mask;
 176         uint8_t i;
 177
 178         for (i = 0; i < N_SENSORS; i++) {
 179                 mask = 1 << i;
 180
 181                 if (thresholds[i]) {
 182                         if (distances[i] == -1 || distances[i] == 0) {
 183                                 err_b |= mask;
 184                         } else if (distances[i] > thresholds[i]) {
 185                                 free_b |= mask;
 186                         }
 187                 }
 188         }
 189
 190         free_bitmap = free_b;
 191         err_bitmap  = err_b;
 192
 193         if (led1_sensors) {
 194                 if (led1_sensors & err_bitmap) {
 195                         led_set(0, 2);
 196                 } else if (led1_sensors & free_bitmap) {
 197                         led_set(0, 1);
 198                 } else {
 199                         led_set(0, 0);
 200                 }
 201         }
 202
 203         if (led2_sensors) {
 204                 if (led2_sensors & err_bitmap) {
 205                         led_set(1, 2);
 206                 } else if (led2_sensors & free_bitmap) {
 207                         led_set(1, 1);
 208                 } else {
 209                         led_set(1, 0);
 210                 }
 211         }
 212 }
 213
 214 uint8_t hold_reg_is_valid(uint16_t reg, uint16_t val)
 215 {
 216         if (reg == MB_HOLD_REGS_BASE)
 217                 return val > 0 && val <= 247;
 218
 219         return 1;
 220 }
 221
 222 int main()
 223 {
 224         modbus_init(0);
 225
 226         // output pins
 227         DDRD |= _BV(PD7); // Trig D
 228         DDRB |= _BV(PB4) | _BV(PB5); // Trig B, LED 2
 229         DDRC |= _BV(PC4) | _BV(PC5); // Trig C, LED 1
 230
 231         // set up the timer
 232         TCCR1A = 0;
 233         TCCR1B = _BV(CS12)|_BV(CS10); // CLK/1024
 234
 235         // enable interrupts
 236         sei();
 237
 238         while(1) {
 239                 uint8_t trig;
 240                 for (trig = 0; trig < N_TRIGGERS; trig++) {
 241                         uint16_t now;
 242                         do_measurement(trig);
 243                         now = get_clock();
 244                         while (get_clock()-now < MEASUREMENT_WAIT)
 245                                 modbus_poll();
 246                 }
 247
 248                 eval_bitmaps();
 249                 leds_update(); // might be written from modbus
 250 //              led_set(0,
 251 //                      distances[4] > 100 || distances[11] > 100);
 252         }
 253 }
 254