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
|
/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBED_PWMOUT_H
#define MBED_PWMOUT_H
#include "platform/platform.h"
#if DEVICE_PWMOUT
#include "hal/pwmout_api.h"
#include "platform/mbed_critical.h"
namespace mbed {
/** \addtogroup drivers */
/** @{*/
/** A pulse-width modulation digital output
*
* @Note Synchronization level: Interrupt safe
*
* Example
* @code
* // Fade a led on.
* #include "mbed.h"
*
* PwmOut led(LED1);
*
* int main() {
* while(1) {
* led = led + 0.01;
* wait(0.2);
* if(led == 1.0) {
* led = 0;
* }
* }
* }
* @endcode
*
* @note
* On the LPC1768 and LPC2368, the PWMs all share the same
* period - if you change the period for one, you change it for all.
* Although routines that change the period maintain the duty cycle
* for its PWM, all other PWMs will require their duty cycle to be
* refreshed.
*/
class PwmOut {
public:
/** Create a PwmOut connected to the specified pin
*
* @param pin PwmOut pin to connect to
*/
PwmOut(PinName pin) {
core_util_critical_section_enter();
pwmout_init(&_pwm, pin);
core_util_critical_section_exit();
}
/** Set the ouput duty-cycle, specified as a percentage (float)
*
* @param value A floating-point value representing the output duty-cycle,
* specified as a percentage. The value should lie between
* 0.0f (representing on 0%) and 1.0f (representing on 100%).
* Values outside this range will be saturated to 0.0f or 1.0f.
*/
void write(float value) {
core_util_critical_section_enter();
pwmout_write(&_pwm, value);
core_util_critical_section_exit();
}
/** Return the current output duty-cycle setting, measured as a percentage (float)
*
* @returns
* A floating-point value representing the current duty-cycle being output on the pin,
* measured as a percentage. The returned value will lie between
* 0.0f (representing on 0%) and 1.0f (representing on 100%).
*
* @note
* This value may not match exactly the value set by a previous <write>.
*/
float read() {
core_util_critical_section_enter();
float val = pwmout_read(&_pwm);
core_util_critical_section_exit();
return val;
}
/** Set the PWM period, specified in seconds (float), keeping the duty cycle the same.
*
* @note
* The resolution is currently in microseconds; periods smaller than this
* will be set to zero.
*/
void period(float seconds) {
core_util_critical_section_enter();
pwmout_period(&_pwm, seconds);
core_util_critical_section_exit();
}
/** Set the PWM period, specified in milli-seconds (int), keeping the duty cycle the same.
*/
void period_ms(int ms) {
core_util_critical_section_enter();
pwmout_period_ms(&_pwm, ms);
core_util_critical_section_exit();
}
/** Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
*/
void period_us(int us) {
core_util_critical_section_enter();
pwmout_period_us(&_pwm, us);
core_util_critical_section_exit();
}
/** Set the PWM pulsewidth, specified in seconds (float), keeping the period the same.
*/
void pulsewidth(float seconds) {
core_util_critical_section_enter();
pwmout_pulsewidth(&_pwm, seconds);
core_util_critical_section_exit();
}
/** Set the PWM pulsewidth, specified in milli-seconds (int), keeping the period the same.
*/
void pulsewidth_ms(int ms) {
core_util_critical_section_enter();
pwmout_pulsewidth_ms(&_pwm, ms);
core_util_critical_section_exit();
}
/** Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
*/
void pulsewidth_us(int us) {
core_util_critical_section_enter();
pwmout_pulsewidth_us(&_pwm, us);
core_util_critical_section_exit();
}
/** A operator shorthand for write()
*/
PwmOut& operator= (float value) {
// Underlying call is thread safe
write(value);
return *this;
}
PwmOut& operator= (PwmOut& rhs) {
// Underlying call is thread safe
write(rhs.read());
return *this;
}
/** An operator shorthand for read()
*/
operator float() {
// Underlying call is thread safe
return read();
}
protected:
pwmout_t _pwm;
};
} // namespace mbed
#endif
#endif
/** @}*/
|
