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
|
//
// main.ino
//
// Testing controlling ESCs (and motors).
#include <limits.h>
// number of ESCs
#define NUM_CHANNELS 4
// pin number of first channel
#define FIRST_PIN 4
// 0 <= channel value <= this constant
#define MAX_CHANNEL_VALUE 1000UL
// pulse width when channel value is 0 and MAX_CHANNEL_VALUE in microseconds
#define MIN_PULSE_WIDTH 1150UL
#define MAX_PULSE_WIDTH 1750UL
// interval between rising edges of successinve channels in microseconds
#define CHANNEL_INTERVAL ( MAX_PULSE_WIDTH + 500UL )
// duration of a whole frame (including the pulse) in microseconds
#define FRAME_DURATION 20000UL
// test ramping
#define RAMP_START 0
#define RAMP_MAX 900
// deltas (applied every 100 milliseconds)
#define RAMP_UP_DELTA 4
#define RAMP_DOWN_DELTA -10
void setup()
{
// setup outputs
for( int pin = FIRST_PIN; pin < FIRST_PIN + NUM_CHANNELS; pin++ ) {
pinMode( pin, OUTPUT );
digitalWrite( pin, LOW );
}
Serial.begin( 9600 );
}
signed long calculate_duration( unsigned long then, unsigned long now )
{
// does it look like now has overflowed (and wrapped)?
if( now < then && now < ( ULONG_MAX / 2 ) && then > ( ULONG_MAX / 2 ) )
return now + ( ULONG_MAX - then );
// else, calculate duration
else
return now - then;
}
void update_channels( int channels[] )
{
static int event = NUM_CHANNELS * 2;
unsigned long now = micros();
static unsigned long frame_start = now - FRAME_DURATION;
static unsigned long next_event_at;
if( now >= next_event_at )
{
// action event
digitalWrite( FIRST_PIN + ( event / 2 ), ( event & 1 )? LOW : HIGH );
// move to next event
if( ++event >= NUM_CHANNELS * 2 ) {
event = 0;
frame_start += FRAME_DURATION;
}
// calculate the time that the next event will occur
next_event_at = frame_start + ( event / 2 ) * CHANNEL_INTERVAL;
if( event & 1 )
next_event_at += MIN_PULSE_WIDTH + channels[ event / 2 ] *
( MAX_PULSE_WIDTH - MIN_PULSE_WIDTH ) / MAX_CHANNEL_VALUE;
// Serial.print( event / 2 );
// Serial.print( ( event & 1 )? 'v' : '^' );
// Serial.print( " " );
// Serial.println( next_event_at );
if( event == 1 ) {
unsigned long width = MIN_PULSE_WIDTH +
(unsigned long)channels[ event / 2 ] *
( MAX_PULSE_WIDTH - MIN_PULSE_WIDTH ) / MAX_CHANNEL_VALUE;
Serial.print( channels[ event / 2 ] );
Serial.print( " " );
Serial.println( width );
}
}
}
void loop()
{
int channels[ NUM_CHANNELS ];
for( int a = 0; a < NUM_CHANNELS; a++ )
channels[ a ] = 0;
// test ramping state
unsigned long then = millis();
int val = RAMP_START, delta = RAMP_UP_DELTA;
while( true )
{
update_channels( channels );
// update ramp value and set channel 0 value
unsigned long now = millis();
if( now > then + 100 ) {
then = now;
val += delta;
if( val >= RAMP_MAX ) {
val = RAMP_MAX;
delta = RAMP_DOWN_DELTA;
}
if( val <= 0 ) {
val = 0;
delta = 0;
}
channels[ 0 ] = val;
}
}
}
|