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
|
/* 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.
*/
#include "mbed_assert.h"
#include "pwmout_api.h"
#if DEVICE_PWMOUT
#include "cmsis.h"
#include "pinmap.h"
#include "fsl_ftm_hal.h"
#include "fsl_mcg_hal.h"
#include "fsl_clock_manager.h"
#include "PeripheralPins.h"
static float pwm_clock_mhz;
void pwmout_init(pwmout_t* obj, PinName pin) {
PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
MBED_ASSERT(pwm != (PWMName)NC);
obj->pwm_name = pwm;
uint32_t pwm_base_clock;
CLOCK_SYS_GetFreq(kBusClock, &pwm_base_clock);
float clkval = (float)pwm_base_clock / 1000000.0f;
uint32_t clkdiv = 0;
while (clkval > 1) {
clkdiv++;
clkval /= 2.0f;
if (clkdiv == 7) {
break;
}
}
pwm_clock_mhz = clkval;
uint32_t channel = pwm & 0xF;
uint32_t instance = pwm >> TPM_SHIFT;
uint32_t ftm_addrs[] = FTM_BASE_ADDRS;
CLOCK_SYS_EnableFtmClock(instance);
FTM_HAL_SetTofFreq(ftm_addrs[instance], 3);
FTM_HAL_SetClockSource(ftm_addrs[instance], kClock_source_FTM_SystemClk);
FTM_HAL_SetClockPs(ftm_addrs[instance], (ftm_clock_ps_t)clkdiv);
FTM_HAL_SetCounter(ftm_addrs[instance], 0);
// default to 20ms: standard for servos, and fine for e.g. brightness control
pwmout_period_ms(obj, 20);
pwmout_write (obj, 0);
ftm_pwm_param_t config = {
.mode = kFtmEdgeAlignedPWM,
.edgeMode = kFtmHighTrue
};
FTM_HAL_EnablePwmMode(ftm_addrs[instance], &config, channel);
// Wire pinout
pinmap_pinout(pin, PinMap_PWM);
}
void pwmout_free(pwmout_t* obj) {
}
void pwmout_write(pwmout_t* obj, float value) {
uint32_t instance = obj->pwm_name >> TPM_SHIFT;
if (value < 0.0f) {
value = 0.0f;
} else if (value > 1.0f) {
value = 1.0f;
}
uint32_t ftm_addrs[] = FTM_BASE_ADDRS;
uint16_t mod = FTM_HAL_GetMod(ftm_addrs[instance]);
uint32_t new_count = (uint32_t)((float)(mod) * value);
// Stop FTM clock to ensure instant update of MOD register
FTM_HAL_SetClockSource(ftm_addrs[instance], kClock_source_FTM_None);
FTM_HAL_SetChnCountVal(ftm_addrs[instance], obj->pwm_name & 0xF, new_count);
FTM_HAL_SetCounter(ftm_addrs[instance], 0);
FTM_HAL_SetClockSource(ftm_addrs[instance], kClock_source_FTM_SystemClk);
}
float pwmout_read(pwmout_t* obj) {
uint32_t ftm_addrs[] = FTM_BASE_ADDRS;
uint16_t count = FTM_HAL_GetChnCountVal(ftm_addrs[obj->pwm_name >> TPM_SHIFT], obj->pwm_name & 0xF, 0);
uint16_t mod = FTM_HAL_GetMod(ftm_addrs[obj->pwm_name >> TPM_SHIFT]);
if (mod == 0)
return 0.0;
float v = (float)(count) / (float)(mod);
return (v > 1.0f) ? (1.0f) : (v);
}
void pwmout_period(pwmout_t* obj, float seconds) {
pwmout_period_us(obj, seconds * 1000000.0f);
}
void pwmout_period_ms(pwmout_t* obj, int ms) {
pwmout_period_us(obj, ms * 1000);
}
// Set the PWM period, keeping the duty cycle the same.
void pwmout_period_us(pwmout_t* obj, int us) {
uint32_t instance = obj->pwm_name >> TPM_SHIFT;
uint32_t ftm_addrs[] = FTM_BASE_ADDRS;
float dc = pwmout_read(obj);
// Stop FTM clock to ensure instant update of MOD register
FTM_HAL_SetClockSource(ftm_addrs[instance], kClock_source_FTM_None);
FTM_HAL_SetMod(ftm_addrs[instance], (uint32_t)(pwm_clock_mhz * (float)us) - 1);
pwmout_write(obj, dc);
FTM_HAL_SetClockSource(ftm_addrs[instance], kClock_source_FTM_SystemClk);
}
void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
}
void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
pwmout_pulsewidth_us(obj, ms * 1000);
}
void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
uint32_t ftm_addrs[] = FTM_BASE_ADDRS;
uint32_t value = (uint32_t)(pwm_clock_mhz * (float)us);
FTM_HAL_SetChnCountVal(ftm_addrs[obj->pwm_name >> TPM_SHIFT], obj->pwm_name & 0xF, value);
}
#endif
|
