blob: ea7cf55e00c4642f5f24dd7862108c0025524d65 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
/*
* Tacho.c
* Author: noname7890
*/
#define F_CPU 1000000
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#define _PRIM PORTC //Right digit
#define _SEC PORTD //Left digit
#define _WHEEL_SIZE 207 //In cm
//Define characters (negative)
#define _C1 0b10101111
#define _C2 0b11001000
#define _C3 0b10101000
#define _C4 0b10100101
#define _C5 0b10110000
#define _C6 0b10010001
#define _C7 0b10101110
#define _C8 0b10000000
#define _C9 0b10100000
#define _C0 0b10000010
#define _C_ 0b11111101
#define _CCLEAR 255
uint32_t cntr; //counter for Timer
unsigned int speed; //global var to save the calculated speed in
ISR(TIMER0_OVF_vect) //ISR for TIMER0 overflow
{
cntr++;
}
inline void calcSpeed(void)
{
float tmrSpeed = F_CPU / 256; //The timer overflow speed in Hz
float tmrTime = 1 / tmrSpeed; //The timer overflow speed in s
float comTime = tmrTime * cntr; //calculate the total time
float mps = (_WHEEL_SIZE / 100) / comTime; //Convert wheelsize to m and derive by the complete time
float kmph = mps * 3.6; //km/h = m/s * 3.6
speed = (int)kmph; //cast to int and write into global var speed
}//calcSpeed()
inline void render(int _screen)
{
char cNr[16];
int i1, i2;
itoa(_screen, cNr, 10); //convert int to string for rendering
/*
* If _screen is smaller than 10, the cNr contains 1xxxxxxxxxx, but if it is bigger than 10 it looks like this: 10xxxxxxxxxx
* So I have to change the digits
*/
if(_screen < 10)
{
i1 = 0;
i2 = 1;
cNr[1] = '0';
}
else
{
i1 = 1;
i2 = 0;
}
if(_screen > 99 || _screen < 0)
{
_SEC = _PRIM = _C_;
}
else
{
switch (cNr[i1]) //first character
{
case '0':
_PRIM = _C0;
PORTB &= ~(1<<PB2);
break;
case '1':
_PRIM = _C1;
PORTB &= ~(1<<PB2);
break;
case '2':
_PRIM = _C2;
PORTB |= (1<<PB2);
break;
case '3':
_PRIM = _C3;
PORTB &= ~(1<<PB2);
break;
case '4':
_PRIM = _C4;
PORTB &= ~(1<<PB2);
break;
case '5':
_PRIM = _C5;
PORTB &= ~(1<<PB2);
break;
case '6':
_PRIM = _C6;
PORTB &= ~(1<<PB2);
break;
case '7':
_PRIM = _C7;
PORTB &= ~(1<<PB2);
break;
case '8':
_PRIM = _C8;
PORTB &= ~(1<<PB2);
break;
case '9':
_PRIM = _C9;
PORTB &= ~(1<<PB2);
break;
}
switch (cNr[i2])//second character
{
case '0':
_SEC = _C0;
break;
case '1':
_SEC = _C1;
break;
case '2':
_SEC = _C2;
break;
case '3':
_SEC = _C3;
break;
case '4':
_SEC = _C4;
break;
case '5':
_SEC = _C5;
break;
case '6':
_SEC = _C6;
break;
case '7':
_SEC = _C7;
break;
case '8':
_SEC = _C8;
break;
case '9':
_SEC = _C9;
break;
}
}
}//render()
int main(void)
{
TCCR0 = (1 << CS00); // Prescaler 1
TIMSK = (1<<TOIE0); //Enable Overflowinterrupt
cntr = 0; //init counter for Timer
DDRC = DDRD = 255; // Output for screen pins
DDRB |= (1<<PB2);
DDRB &= ~(1<<PB1);
sei(); //enable interrupts
render(0); //init the display
while(1)//main loop
{
while(PINB & (1 << PB1) && cntr < 30000){} // wait for reedcontact on PB1
TCCR0 = ~(1 << CS00); //disable counter
cli(); //disable interrupts
calcSpeed();
//reset all variables
cntr = 0; //Reset counter
TCNT0 = 0; //Reset Timer
sei();//enable interrupts
TCCR0 = (1 << CS00); //enable counter
render(speed);//render the calculated speed
_delay_ms(100);
}
}//main()
|