Frequency Counter

1/*
2 * LCD Counter
3 * Created: 12/08/2017 23:34:47
4 *  Author:  moty22.co.uk
5*/
6
7#include <LiquidCrystal.h>
8
9  byte overF=0;
10  unsigned long freq;
11  double period;
12  
13   // initialize the library  with the numbers of the interface pins
14  LiquidCrystal lcd(12, 11, A2, A3, A4,  A5);
15
16// the setup function runs once when you press reset or power the board
17void  setup() {
18 
19    lcd.begin(16, 2);   // set up the LCD's number of columns  and rows:
20    
21          //1 Hz timer
22    OCR0A = 249;
23    TCCR0A =  _BV(WGM00) | _BV(WGM01) | _BV(COM0A0); //   
24    TCCR0B = _BV(WGM02) | _BV(CS02)  | _BV(CS01);  //  PWM mode, input T0 pin D4
25    pinMode(6, OUTPUT);
26    
27      //250 Hz - timer2
28    OCR2A =249;
29    OCR2B = 125;  
30    TCCR2A =  _BV(COM2B1) | _BV(COM2B0) | _BV(WGM21) | _BV(WGM20);  //output B in phase, fast  PWM mode
31    TCCR2B = _BV(WGM22) | _BV(CS22) | _BV(CS21); // set prescaler to  256 and start the timer
32    pinMode(3, OUTPUT);
33    
34        //  counter  input T1 pin D5
35    OCR1A = 32767;   //32768 counts
36    TCCR1A = _BV(WGM10)  | _BV(WGM11) | _BV(COM1A0); //   
37    TCCR1B =_BV(WGM12) | _BV(WGM13) | _BV(CS12)  | _BV(CS11); //input pin D5
38    pinMode(9, OUTPUT);
39    
40    lcd.setCursor(7,  0); // top middle
41    lcd.print("hi");
42
43}
44
45  
46  // the loop  function runs over and over again forever
47void loop() {
48
49      //wait for  high
50    while(digitalRead(6)){}
51    while(!digitalRead(6)){}
52      //start  the count
53    TIFR1 = _BV(OCF1A);    //reset int
54    OCR1A = 32767; 
55    TCNT1=0;
56    overF=0;
57    while(digitalRead(6)){
58    if(TIFR1 & (1<<OCF1A)) {++overF;  TIFR1 = _BV(OCF1A);}   //overflow 
59    }
60        //count end
61    freq =  (unsigned long)TCNT1 + ((unsigned long)overF * 32768);
62    period = 1000000 /  (double)freq;
63    if(freq == 0){period=0;}
64    
65    lcd.clear();
66    lcd.setCursor(3,  0); // top line
67    lcd.print(freq,DEC);
68    lcd.setCursor(11, 0);
69    lcd.print("Hz");
70    lcd.setCursor(3, 1);
71    lcd.print(period,DEC);
72    lcd.setCursor(10,  1);
73    lcd.print(" uS   ");
74}
75
76
77

1/*
2 * LCD Counter
3 * Created: 12/08/2017 23:34:47
4 *  Author:
5  moty22.co.uk
6*/
7
8#include <LiquidCrystal.h>
9
10  byte overF=0;
11
12  unsigned long freq;
13  double period;
14  
15   // initialize the library
16  with the numbers of the interface pins
17  LiquidCrystal lcd(12, 11, A2, A3, A4,
18  A5);
19
20// the setup function runs once when you press reset or power the board
21void
22  setup() {
23 
24    lcd.begin(16, 2);   // set up the LCD's number of columns
25  and rows:
26    
27          //1 Hz timer
28    OCR0A = 249;
29    TCCR0A =
30  _BV(WGM00) | _BV(WGM01) | _BV(COM0A0); //   
31    TCCR0B = _BV(WGM02) | _BV(CS02)
32  | _BV(CS01);  //  PWM mode, input T0 pin D4
33    pinMode(6, OUTPUT);
34    
35
36      //250 Hz - timer2
37    OCR2A =249;
38    OCR2B = 125;  
39    TCCR2A =
40  _BV(COM2B1) | _BV(COM2B0) | _BV(WGM21) | _BV(WGM20);  //output B in phase, fast
41  PWM mode
42    TCCR2B = _BV(WGM22) | _BV(CS22) | _BV(CS21); // set prescaler to
43  256 and start the timer
44    pinMode(3, OUTPUT);
45    
46        //  counter
47  input T1 pin D5
48    OCR1A = 32767;   //32768 counts
49    TCCR1A = _BV(WGM10)
50  | _BV(WGM11) | _BV(COM1A0); //   
51    TCCR1B =_BV(WGM12) | _BV(WGM13) | _BV(CS12)
52  | _BV(CS11); //input pin D5
53    pinMode(9, OUTPUT);
54    
55    lcd.setCursor(7,
56  0); // top middle
57    lcd.print("hi");
58
59}
60
61  
62  // the loop
63  function runs over and over again forever
64void loop() {
65
66      //wait for
67  high
68    while(digitalRead(6)){}
69    while(!digitalRead(6)){}
70      //start
71  the count
72    TIFR1 = _BV(OCF1A);    //reset int
73    OCR1A = 32767; 
74    TCNT1=0;
75
76    overF=0;
77    while(digitalRead(6)){
78    if(TIFR1 & (1<<OCF1A)) {++overF;
79  TIFR1 = _BV(OCF1A);}   //overflow 
80    }
81        //count end
82    freq =
83  (unsigned long)TCNT1 + ((unsigned long)overF * 32768);
84    period = 1000000 /
85  (double)freq;
86    if(freq == 0){period=0;}
87    
88    lcd.clear();
89    lcd.setCursor(3,
90  0); // top line
91    lcd.print(freq,DEC);
92    lcd.setCursor(11, 0);
93    lcd.print("Hz");
94
95    lcd.setCursor(3, 1);
96    lcd.print(period,DEC);
97    lcd.setCursor(10,
98  1);
99    lcd.print(" uS   ");
100}
101
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103