1 // Copyright 2013 Olivier Gillet.
2 //
3 // Author: Olivier Gillet (ol.gillet@gmail.com)
4 //
5 // Permission is hereby granted, free of charge, to any person obtaining a copy
6 // of this software and associated documentation files (the "Software"), to deal
7 // in the Software without restriction, including without limitation the rights
8 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
9 // copies of the Software, and to permit persons to whom the Software is
10 // furnished to do so, subject to the following conditions:
11 //
12 // The above copyright notice and this permission notice shall be included in
13 // all copies or substantial portions of the Software.
14 //
15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
21 // THE SOFTWARE.
22 //
23 // See http://creativecommons.org/licenses/MIT/ for more information.
24 //
25 // -----------------------------------------------------------------------------
26 //
27 // Driver for PWM (controlling VCF).
28 
29 #ifndef STREAMS_DRIVERS_PWM_H_
30 #define STREAMS_DRIVERS_PWM_H_
31 
32 #include "stmlib/stmlib.h"
33 
34 #include <stm32f10x_conf.h>
35 
36 namespace streams {
37 
38 const uint16_t kPwmResolution = 10;  // 10 bits -> 70kHz PWM.
39 
40 class Pwm {
41  public:
Pwm()42   Pwm() { }
~Pwm()43   ~Pwm() { }
44 
45   void Init();
46 
Write(uint8_t channel,uint16_t value)47   void Write(uint8_t channel, uint16_t value) {
48     filtered_value_[channel] += (value - filtered_value_[channel]) >> 4;
49     uint16_t channel_value = filtered_value_[channel] >> (16 - kPwmResolution);
50     if (channel == 0) {
51       TIM1->CCR3 = channel_value;
52     } else {
53       TIM1->CCR4 = channel_value;
54     }
55   }
56 
57  private:
58   uint16_t filtered_value_[2];
59   DISALLOW_COPY_AND_ASSIGN(Pwm);
60 };
61 
62 }  // namespace streams
63 
64 #endif  // STREAMS_DRIVERS_DAC_H_
65