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
|
/*
* Xytronic LF-1600
* Current PWM
*
* Copyright (c) 2015-2017 Michael Buesch <m@bues.ch>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "pwm_current.h"
#include "scale.h"
#include "controller_current.h"
#include "util.h"
#include <avr/io.h>
/* The max duty value (which actually is min current).
* Note that changing this changes the PWM frequency.
*/
#define PWMCURR_MAX_DUTY 0x1FFF
void pwmcurr_set(fixpt_t current_amps)
{
uint16_t duty;
/* Scale amps to duty cycle duration.
* Scaling is inverse:
* 0 -> full current
* pwm-max -> no current
*/
duty = (uint16_t)unscale(current_amps,
float_to_fixpt(CONTRCURR_NEGLIM),
float_to_fixpt(CONTRCURR_POSLIM),
(int16_t)PWMCURR_MAX_DUTY, 0);
/* Program the hardware */
OCR1A = duty;
}
void pwmcurr_init(void)
{
build_assert(F_CPU == 8000000UL);
/* Configure the port as output; high level. */
PORTB |= (1 << PB1);
DDRB |= (1 << DDB1);
/* Set frequency and initial duty cycle. */
ICR1 = (uint16_t)PWMCURR_MAX_DUTY;
OCR1A = (uint16_t)PWMCURR_MAX_DUTY;
/* Enable timer: Fast PWM (Mode 14), OC1A clr/set, PS 256 */
TCCR1A = (1 << COM1A1) | (0 << COM1A0) |
(0 << COM1B1) | (0 << COM1B0) |
(1 << WGM11) | (0 << WGM10);
TCCR1C = 0;
TCCR1B = (1 << WGM13) | (1 << WGM12) |
(1 << CS12) | (0 << CS11) | (0 << CS10);
TCNT1 = 0;
}
|
