firmware/firmware.c

   1 #include <avr/io.h>
   2 #include <avr/interrupt.h>
   3 #include <util/delay.h>
   4 #include <stdio.h>
   5 #include "modbus.h"
   6
   7 #define TIMEOUT 0x2FF
   8
   9 #define N_TRIGGERS 3
  10 #define N_SENSORS 12
  11 #define N_TRIG_SENSORS 4
  12
  13 // static int16_t distances[N_SENSORS];
  14
  15 // hold_regs[0] is unit ID
  16 #define thresholds      (hold_regs+1)
  17 #define led1_sensors    (hold_regs[13])
  18 #define led2_sensors    (hold_regs[14])
  19
  20 #define led_bitmap      (hold_regs[MB_N_HOLD_REGS_EEPROM])
  21 #define distances       (hold_regs+MB_N_HOLD_REGS_EEPROM+1)
  22 #define free_bitmap     (hold_regs[MB_N_HOLD_REGS_EEPROM+13])
  23 #define err_bitmap      (hold_regs[MB_N_HOLD_REGS_EEPROM+14])
  24
  25 static void pull_trigger(uint8_t trig)
  26 {
  27         switch (trig) {
  28         case 0: PORTD |= _BV(PD7); _delay_us(10); PORTD &= ~_BV(PD7); break;
  29         case 1: PORTB |= _BV(PB4); _delay_us(10); PORTB &= ~_BV(PB4); break;
  30         case 2: PORTC |= _BV(PC4); _delay_us(10); PORTC &= ~_BV(PC4); break;
  31         }
  32 }
  33
  34 static uint16_t get_pin(uint8_t trig)
  35 {
  36         switch (trig) {
  37         case 0: return (PIND & 0x78) >> 3;
  38         case 1: return PINB & 0x0F;
  39         default: return PINC & 0x0F;
  40         }
  41 }
  42
  43 static void do_measurement(unsigned char trig)
  44 {
  45         uint16_t starttimes[N_TRIG_SENSORS], starttime;
  46         uint8_t to_start = (1 << N_TRIG_SENSORS) - 1;
  47         uint8_t to_measure = 0, i;
  48
  49         pull_trigger(trig);
  50
  51         starttime = TCNT1;
  52
  53         while (to_start || to_measure) {
  54                 uint8_t bits = 0;
  55                 uint16_t now = TCNT1;
  56
  57                 if (now-starttime >= TIMEOUT)
  58                         break;
  59
  60                 bits = get_pin(trig);
  61
  62                 for (i = 0; i < N_TRIG_SENSORS; i++) {
  63                         uint8_t mask = 1 << i;
  64
  65                         if ((to_start & mask) && (bits & mask)) {
  66                                 // echo start
  67                                 starttimes[i] = now;
  68                                 to_start &= ~mask;
  69                                 to_measure |= mask;
  70                         } else if ((to_measure & mask) && !(bits & mask)) {
  71                                 // echo end
  72                                 to_measure &= ~mask;
  73                                 distances[trig*N_TRIG_SENSORS + i]
  74                                         = now - starttimes[i];
  75                         }
  76                 }
  77         }
  78
  79         for (i = 0; i < N_TRIG_SENSORS; i++)
  80                 if (to_start & (1 << i))
  81                         distances[trig*N_TRIG_SENSORS + i] = -1;
  82                 else if (to_measure & (1 << i))
  83                         distances[trig*N_TRIG_SENSORS + i] = 0;
  84 }
  85
  86 static void do_measurements()
  87 {
  88         uint8_t trig;
  89
  90         for (trig = 0; trig < N_TRIGGERS; trig++) {
  91                 do_measurement(trig);
  92                 _delay_ms(200);
  93         }
  94 }
  95
  96 static void led_set(uint8_t led, uint8_t state)
  97 {
  98         if (led == 0) {
  99                 if (state) {
 100                         PORTC |= _BV(PC5);
 101                         led_bitmap |= 1;
 102                 } else {
 103                         PORTC &= ~_BV(PC5);
 104                         led_bitmap &= ~1;
 105                 }
 106         } else {
 107                 if (state) {
 108                         PORTB |= _BV(PB5);
 109                         led_bitmap |= 2;
 110                 } else {
 111                         PORTB &= ~_BV(PB5);
 112                         led_bitmap &= ~2;
 113                 }
 114         }
 115 }
 116
 117 static void eval_bitmaps()
 118 {
 119         uint16_t free_b = 0, err_b = 0, mask;
 120         uint8_t i;
 121
 122         for (i = 0; i < N_SENSORS; i++) {
 123                 mask = 1 << i;
 124
 125                 if (thresholds[i]) {
 126                         if (distances[i] == -1 || distances[i] == 0) {
 127                                 err_b |= mask;
 128                         } else if (distances[i] > thresholds[i]) {
 129                                 free_b |= mask;
 130                         }
 131                 }
 132         }
 133
 134         free_bitmap = free_b;
 135         err_bitmap  = err_b;
 136
 137         if (led1_sensors) {
 138                 if (led1_sensors & free_bitmap) {
 139                         led_set(0, 1);
 140                 } else {
 141                         led_set(0, 0);
 142                 }
 143         }
 144
 145         if (led2_sensors) {
 146                 if (led2_sensors & free_bitmap) {
 147                         led_set(1, 1);
 148                 } else {
 149                         led_set(1, 0);
 150                 }
 151         }
 152 }
 153
 154 uint8_t hold_reg_is_valid(uint16_t reg, uint16_t val)
 155 {
 156         if (reg == MB_HOLD_REGS_BASE)
 157                 return val > 0 && val <= 247;
 158
 159         return 1;
 160 }
 161
 162 int main()
 163 {
 164         modbus_init(0);
 165
 166         // output pins
 167         DDRD |= _BV(PD7); // Trig D
 168         DDRB |= _BV(PB4) | _BV(PB5); // Trig B, LED 2
 169         DDRC |= _BV(PC4) | _BV(PC5); // Trig C, LED 1
 170
 171         // set up the timer
 172         TCCR1A = 0;
 173         TCCR1B = _BV(CS12)|_BV(CS10); // CLK/1024
 174
 175         // enable interrupts
 176         sei();
 177
 178         while(1) {
 179                 uint8_t trig;
 180                 for (trig = 0; trig < N_TRIGGERS; trig++) {
 181                         uint16_t now;
 182                         do_measurement(trig);
 183                         now = TCNT1;
 184                         while (TCNT1-now < 200)
 185                                 modbus_poll();
 186                 }
 187
 188                 eval_bitmaps();
 189 //              led_set(0,
 190 //                      distances[4] > 100 || distances[11] > 100);
 191         }
 192 }
 193