2 #include <avr/interrupt.h>
3 #include <util/delay.h>
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)
14 #define N_TRIG_SENSORS 4
16 // static int16_t distances[N_SENSORS];
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])
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 #define err_counts (hold_regs+MB_N_HOLD_REGS_EEPROM+41)
30 static void pull_trigger(uint8_t trig)
33 case 0: PORTD |= _BV(PD7); _delay_us(10); PORTD &= ~_BV(PD7); break;
34 case 1: PORTB |= _BV(PB4); _delay_us(10); PORTB &= ~_BV(PB4); break;
35 case 2: PORTC |= _BV(PC4); _delay_us(10); PORTC &= ~_BV(PC4); break;
39 static uint16_t get_pin(uint8_t trig)
42 case 0: return (PIND & 0x78) >> 3;
43 case 1: return PINB & 0x0F;
44 default: return PINC & 0x0F;
48 static void do_measurement(unsigned char trig)
50 uint16_t starttimes[N_TRIG_SENSORS], starttime;
51 uint8_t to_start = (1 << N_TRIG_SENSORS) - 1;
52 uint8_t to_measure = 0, i;
57 starttime = get_clock();
59 while (to_start || to_measure) {
63 if (now-starttime >= ECHO_TIMEOUT)
68 for (i = 0; i < N_TRIG_SENSORS; i++) {
69 uint8_t mask = 1 << i;
71 if ((to_start & mask) && (bits & mask)) {
76 } else if ((to_measure & mask) && !(bits & mask)) {
77 #if MEASUREMENT_SHIFT > 0
81 uint8_t idx = trig*N_TRIG_SENSORS+i;
84 new_d = now - starttimes[i];
85 if (new_d > max_distances[idx])
86 max_distances[idx] = new_d;
88 #if MEASUREMENT_SHIFT > 0
89 old_d = distances[idx];
93 distances[idx] = new_d;
96 (old_d << MEASUREMENT_SHIFT)
99 ) >> MEASUREMENT_SHIFT;
102 distances[idx] = new_d;
108 for (i = 0; i < N_TRIG_SENSORS; i++) {
109 uint8_t off = trig*N_TRIG_SENSORS + i;
111 if (to_start & (1 << i)) { // echo not received
112 uint16_t err_count = err_counts[off] & 0xFF;
113 if (distances[off] != -1 && err_count < 255) {
115 err_counts[off] = (err_counts[off] & 0xFF00)
119 } else if (to_measure & (1 << i)) { // echo pulse too long
120 uint16_t err_count = err_counts[off] >> 8;
122 if (err_count < 255) {
124 err_counts[off] = (err_counts[off] & 0x00FF)
128 * If the echo pulse is too long, do not treat it
129 * as error, just count it as maximum length.
131 distances[off] = now - starttimes[i];
136 static void led_set(uint8_t led, uint8_t state)
169 static void leds_update()
171 if (led_bitmap & 1) {
177 if (led_bitmap & 2) {
183 if (led_bitmap & 4) {
189 if (led_bitmap & 8) {
196 static void eval_bitmaps()
198 uint16_t free_b = 0, err_b = 0, mask;
201 for (i = 0; i < N_SENSORS; i++) {
205 if (distances[i] == -1) {
207 } else if (distances[i] > thresholds[i]) {
213 free_bitmap = free_b;
217 if (led1_sensors & err_bitmap) {
219 } else if (led1_sensors & free_bitmap) {
227 if (led2_sensors & err_bitmap) {
229 } else if (led2_sensors & free_bitmap) {
237 uint8_t hold_reg_is_valid(uint16_t reg, uint16_t val)
239 if (reg == MB_HOLD_REGS_BASE)
240 return val > 0 && val <= 247;
250 DDRD |= _BV(PD7); // Trig D
251 DDRB |= _BV(PB4) | _BV(PB5); // Trig B, LED 2
252 DDRC |= _BV(PC4) | _BV(PC5); // Trig C, LED 1
256 TCCR1B = _BV(CS12)|_BV(CS10); // CLK/1024
263 for (trig = 0; trig < N_TRIGGERS; trig++) {
265 do_measurement(trig);
267 while (get_clock()-now < MEASUREMENT_WAIT)
272 leds_update(); // might be written from modbus
274 // distances[4] > 100 || distances[11] > 100);