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
|
#include <avr/interrupt.h>
#include <wiring.h>
#include <Servo.h>
/*
Servo.h - Hardware Servo Timer Library
Author: Jim Studt, jim@federated.com
Copyright (c) 2007 David A. Mellis. All right reserved.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
uint8_t Servo::attached9 = 0;
uint8_t Servo::attached10 = 0;
void Servo::seizeTimer1()
{
uint8_t oldSREG = SREG;
cli();
TCCR1A = _BV(WGM11); /* Fast PWM, ICR1 is top */
TCCR1B = _BV(WGM13) | _BV(WGM12) /* Fast PWM, ICR1 is top */
| _BV(CS11) /* div 8 clock prescaler */
;
OCR1A = 3000;
OCR1B = 3000;
ICR1 = clockCyclesPerMicrosecond()*(20000L/8); // 20000 uS is a bit fast for the refresh, 20ms, but
// it keeps us from overflowing ICR1 at 20MHz clocks
// That "/8" at the end is the prescaler.
#if defined(__AVR_ATmega168__)
TIMSK1 &= ~(_BV(OCIE1A) | _BV(OCIE1B) | _BV(TOIE1) );
#else
TIMSK &= ~(_BV(TICIE1) | _BV(OCIE1A) | _BV(OCIE1B) | _BV(TOIE1) );
#endif
SREG = oldSREG; // undo cli()
}
void Servo::releaseTimer1() {}
#define NO_ANGLE (0xff)
Servo::Servo() : pin(0), angle(NO_ANGLE) {}
uint8_t Servo::attach(int pinArg)
{
return attach(pinArg, 544, 2400);
}
uint8_t Servo::attach(int pinArg, int min, int max)
{
if (pinArg != 9 && pinArg != 10) return 0;
min16 = min / 16;
max16 = max / 16;
pin = pinArg;
angle = NO_ANGLE;
digitalWrite(pin, LOW);
pinMode(pin, OUTPUT);
if (!attached9 && !attached10) seizeTimer1();
if (pin == 9) {
attached9 = 1;
TCCR1A = (TCCR1A & ~_BV(COM1A0)) | _BV(COM1A1);
}
if (pin == 10) {
attached10 = 1;
TCCR1A = (TCCR1A & ~_BV(COM1B0)) | _BV(COM1B1);
}
return 1;
}
void Servo::detach()
{
// muck with timer flags
if (pin == 9) {
attached9 = 0;
TCCR1A = TCCR1A & ~_BV(COM1A0) & ~_BV(COM1A1);
pinMode(pin, INPUT);
}
if (pin == 10) {
attached10 = 0;
TCCR1A = TCCR1A & ~_BV(COM1B0) & ~_BV(COM1B1);
pinMode(pin, INPUT);
}
if (!attached9 && !attached10) releaseTimer1();
}
void Servo::write(int angleArg)
{
uint16_t p;
if (angleArg < 0) angleArg = 0;
if (angleArg > 180) angleArg = 180;
angle = angleArg;
// bleh, have to use longs to prevent overflow, could be tricky if always a 16MHz clock, but not true
// That 8L on the end is the TCNT1 prescaler, it will need to change if the clock's prescaler changes,
// but then there will likely be an overflow problem, so it will have to be handled by a human.
p = (min16*16L*clockCyclesPerMicrosecond() + (max16-min16)*(16L*clockCyclesPerMicrosecond())*angle/180L)/8L;
if (pin == 9) OCR1A = p;
if (pin == 10) OCR1B = p;
}
uint8_t Servo::read()
{
return angle;
}
uint8_t Servo::attached()
{
if (pin == 9 && attached9) return 1;
if (pin == 10 && attached10) return 1;
return 0;
}
|
