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micropython/ports/esp32/machine_pwm.c

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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include "driver/ledc.h"
#include "esp_err.h"
#include "py/nlr.h"
#include "py/runtime.h"
#include "modmachine.h"
#include "mphalport.h"
// Forward dec'l
extern const mp_obj_type_t machine_pwm_type;
typedef struct _esp32_pwm_obj_t {
mp_obj_base_t base;
gpio_num_t pin;
uint8_t active;
uint8_t channel;
} esp32_pwm_obj_t;
// Which channel has which GPIO pin assigned?
// (-1 if not assigned)
STATIC int chan_gpio[LEDC_CHANNEL_MAX];
// Params for PW operation
// 5khz
#define PWFREQ (5000)
// High speed mode
#define PWMODE (LEDC_HIGH_SPEED_MODE)
// 10-bit resolution (compatible with esp8266 PWM)
#define PWRES (LEDC_TIMER_10_BIT)
// Timer 1
#define PWTIMER (LEDC_TIMER_1)
// Config of timer upon which we run all PWM'ed GPIO pins
STATIC bool pwm_inited = false;
STATIC ledc_timer_config_t timer_cfg = {
.bit_num = PWRES,
.freq_hz = PWFREQ,
.speed_mode = PWMODE,
.timer_num = PWTIMER
};
STATIC void pwm_init(void) {
// Initial condition: no channels assigned
for (int x = 0; x < LEDC_CHANNEL_MAX; ++x) {
chan_gpio[x] = -1;
}
// Init with default timer params
ledc_timer_config(&timer_cfg);
}
STATIC int set_freq(int newval) {
int oval = timer_cfg.freq_hz;
timer_cfg.freq_hz = newval;
if (ledc_timer_config(&timer_cfg) != ESP_OK) {
timer_cfg.freq_hz = oval;
return 0;
}
return 1;
}
/******************************************************************************/
// MicroPython bindings for PWM
STATIC void esp32_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
esp32_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "PWM(%u", self->pin);
if (self->active) {
mp_printf(print, ", freq=%u, duty=%u", timer_cfg.freq_hz,
ledc_get_duty(PWMODE, self->channel));
}
mp_printf(print, ")");
}
STATIC void esp32_pwm_init_helper(esp32_pwm_obj_t *self,
size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_freq, ARG_duty };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_freq, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_duty, MP_ARG_INT, {.u_int = -1} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args,
MP_ARRAY_SIZE(allowed_args), allowed_args, args);
int channel;
int avail = -1;
// Find a free PWM channel, also spot if our pin is
// already mentioned.
for (channel = 0; channel < LEDC_CHANNEL_MAX; ++channel) {
if (chan_gpio[channel] == self->pin) {
break;
}
if ((avail == -1) && (chan_gpio[channel] == -1)) {
avail = channel;
}
}
if (channel >= LEDC_CHANNEL_MAX) {
if (avail == -1) {
mp_raise_ValueError("out of PWM channels");
}
channel = avail;
}
self->channel = channel;
// New PWM assignment
self->active = 1;
if (chan_gpio[channel] == -1) {
ledc_channel_config_t cfg = {
.channel = channel,
.duty = (1 << PWRES) / 2,
.gpio_num = self->pin,
.intr_type = LEDC_INTR_DISABLE,
.speed_mode = PWMODE,
.timer_sel = PWTIMER,
};
if (ledc_channel_config(&cfg) != ESP_OK) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"PWM not supported on pin %d", self->pin));
}
chan_gpio[channel] = self->pin;
}
// Maybe change PWM timer
int tval = args[ARG_freq].u_int;
if (tval != -1) {
if (tval != timer_cfg.freq_hz) {
if (!set_freq(tval)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"Bad frequency %d", tval));
}
}
}
// Set duty cycle?
int dval = args[ARG_duty].u_int;
if (dval != -1) {
dval &= ((1 << PWRES)-1);
ledc_set_duty(PWMODE, channel, dval);
ledc_update_duty(PWMODE, channel);
}
}
STATIC mp_obj_t esp32_pwm_make_new(const mp_obj_type_t *type,
size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
gpio_num_t pin_id = machine_pin_get_id(args[0]);
// create PWM object from the given pin
esp32_pwm_obj_t *self = m_new_obj(esp32_pwm_obj_t);
self->base.type = &machine_pwm_type;
self->pin = pin_id;
self->active = 0;
self->channel = -1;
// start the PWM subsystem if it's not already running
if (!pwm_inited) {
pwm_init();
pwm_inited = true;
}
// start the PWM running for this channel
mp_map_t kw_args;
mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
esp32_pwm_init_helper(self, n_args - 1, args + 1, &kw_args);
return MP_OBJ_FROM_PTR(self);
}
STATIC mp_obj_t esp32_pwm_init(size_t n_args,
const mp_obj_t *args, mp_map_t *kw_args) {
esp32_pwm_init_helper(args[0], n_args - 1, args + 1, kw_args);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(esp32_pwm_init_obj, 1, esp32_pwm_init);
STATIC mp_obj_t esp32_pwm_deinit(mp_obj_t self_in) {
esp32_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in);
int chan = self->channel;
// Valid channel?
if ((chan >= 0) && (chan < LEDC_CHANNEL_MAX)) {
// Mark it unused, and tell the hardware to stop routing
chan_gpio[chan] = -1;
ledc_stop(PWMODE, chan, 0);
self->active = 0;
self->channel = -1;
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(esp32_pwm_deinit_obj, esp32_pwm_deinit);
STATIC mp_obj_t esp32_pwm_freq(size_t n_args, const mp_obj_t *args) {
if (n_args == 1) {
// get
return MP_OBJ_NEW_SMALL_INT(timer_cfg.freq_hz);
}
// set
int tval = mp_obj_get_int(args[1]);
if (!set_freq(tval)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"Bad frequency %d", tval));
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(esp32_pwm_freq_obj, 1, 2, esp32_pwm_freq);
STATIC mp_obj_t esp32_pwm_duty(size_t n_args, const mp_obj_t *args) {
esp32_pwm_obj_t *self = MP_OBJ_TO_PTR(args[0]);
int duty;
if (n_args == 1) {
// get
duty = ledc_get_duty(PWMODE, self->channel);
return MP_OBJ_NEW_SMALL_INT(duty);
}
// set
duty = mp_obj_get_int(args[1]);
duty &= ((1 << PWRES)-1);
ledc_set_duty(PWMODE, self->channel, duty);
ledc_update_duty(PWMODE, self->channel);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(esp32_pwm_duty_obj,
1, 2, esp32_pwm_duty);
STATIC const mp_rom_map_elem_t esp32_pwm_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&esp32_pwm_init_obj) },
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&esp32_pwm_deinit_obj) },
{ MP_ROM_QSTR(MP_QSTR_freq), MP_ROM_PTR(&esp32_pwm_freq_obj) },
{ MP_ROM_QSTR(MP_QSTR_duty), MP_ROM_PTR(&esp32_pwm_duty_obj) },
};
STATIC MP_DEFINE_CONST_DICT(esp32_pwm_locals_dict,
esp32_pwm_locals_dict_table);
const mp_obj_type_t machine_pwm_type = {
{ &mp_type_type },
.name = MP_QSTR_PWM,
.print = esp32_pwm_print,
.make_new = esp32_pwm_make_new,
.locals_dict = (mp_obj_dict_t*)&esp32_pwm_locals_dict,
};
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