circuitpython/ports/nrf/modules/machine/soft_pwm.c
robert-hh e3b877826c nrf/modules/machine/soft_pwm: Add PWM for nrf51x boards using soft PWM.
Using extmod/machine_pwm.c for the Python bindings and the existing
softpwm.c driver, by just adding the interface.

Properties:
- Frequency range 1-3906 Hz.
- All PWM outputs run at the same frequency but can have different duty
  cycles.
- Limited to the P0.x pins.

Since it uses the existing softpwm.c mechanism, it will be affected by
playing music with the music class.
2023-03-10 10:44:02 +11:00

215 lines
7.2 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2023 Robert Hammelrath
*
* 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 "py/runtime.h"
#include "py/mphal.h"
#if MICROPY_PY_MACHINE_SOFT_PWM
#include "softpwm.h"
typedef enum {
DUTY_NOT_SET = 0,
DUTY,
DUTY_U16,
DUTY_NS
} pwm_duty_t;
typedef struct _machine_pwm_obj_t {
mp_obj_base_t base;
uint8_t pwm_pin;
bool defer_start;
uint8_t duty_mode;
uint32_t duty;
uint32_t freq;
} machine_pwm_obj_t;
#define SOFT_PWM_BASE_FREQ (1000000)
#define DUTY_FULL_SCALE (1024)
STATIC void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_pwm_obj_t *self = self_in;
static char *duty_suffix[] = { "", "", "_u16", "_ns" };
mp_printf(print, "<PWM: Pin=%u freq=%dHz duty%s=%d>",
self->pwm_pin, self->freq,
duty_suffix[self->duty_mode], self->duty);
}
// MicroPython bindings for machine API
STATIC void machine_soft_pwm_start(machine_pwm_obj_t *self);
STATIC void mp_machine_pwm_deinit(machine_pwm_obj_t *self);
STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq);
STATIC void mp_machine_pwm_duty_set(machine_pwm_obj_t *self, mp_int_t duty);
STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16);
STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns);
STATIC void mp_machine_pwm_init_helper(machine_pwm_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_freq, ARG_duty, ARG_duty_u16, ARG_duty_ns };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_duty, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_duty_u16, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_duty_ns, MP_ARG_KW_ONLY | 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);
self->defer_start = true;
if (args[ARG_freq].u_int != -1) {
mp_machine_pwm_freq_set(self, args[ARG_freq].u_int);
}
if (args[ARG_duty].u_int != -1) {
mp_machine_pwm_duty_set(self, args[ARG_duty].u_int);
}
if (args[ARG_duty_u16].u_int != -1) {
mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int);
}
if (args[ARG_duty_ns].u_int != -1) {
mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int);
}
self->defer_start = false;
// (Re-)start the PWM.
machine_soft_pwm_start(self);
}
STATIC mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
enum { ARG_pin, ARG_freq, ARG_duty, ARG_duty_u16, ARG_duty_ns, ARG_id };
mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
// check if the PWM pin is valid.
int pwm_pin = mp_hal_get_pin_obj(args[0])->pin;
if (pwm_pin > 31) {
mp_raise_ValueError(MP_ERROR_TEXT("Pin number >31"));
}
machine_pwm_obj_t *self = mp_obj_malloc(machine_pwm_obj_t, &machine_pwm_type);;
self->defer_start = false;
self->pwm_pin = pwm_pin;
self->duty_mode = DUTY_NOT_SET;
self->duty = 0;
self->freq = 0;
// parse the remaining arguments and start the PWM
mp_map_t kw_args;
mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
mp_machine_pwm_init_helper(self, n_args - 1, args + 1, &kw_args);
return MP_OBJ_FROM_PTR(self);
}
STATIC void mp_machine_pwm_deinit(machine_pwm_obj_t *self) {
pwm_release(self->pwm_pin);
}
STATIC mp_obj_t mp_machine_pwm_freq_get(machine_pwm_obj_t *self) {
return MP_OBJ_NEW_SMALL_INT(self->freq);
}
STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) {
if (freq > (SOFT_PWM_BASE_FREQ / 256)) {
mp_raise_ValueError(MP_ERROR_TEXT("frequency out of range"));
}
self->freq = freq;
machine_soft_pwm_start(self);
}
STATIC mp_obj_t mp_machine_pwm_duty_get(machine_pwm_obj_t *self) {
if (self->duty_mode) {
return MP_OBJ_NEW_SMALL_INT(self->duty);
} else if (self->duty_mode == DUTY_U16) {
return MP_OBJ_NEW_SMALL_INT(self->duty * 100 / 65536);
} else {
return MP_OBJ_NEW_SMALL_INT(-1);
}
}
STATIC void mp_machine_pwm_duty_set(machine_pwm_obj_t *self, mp_int_t duty) {
self->duty = duty;
self->duty_mode = DUTY;
machine_soft_pwm_start(self);
}
STATIC mp_obj_t mp_machine_pwm_duty_get_u16(machine_pwm_obj_t *self) {
if (self->duty_mode == DUTY_U16) {
return MP_OBJ_NEW_SMALL_INT(self->duty);
} else if (self->duty_mode == DUTY) {
return MP_OBJ_NEW_SMALL_INT(self->duty * 65536 / 100);
} else {
return MP_OBJ_NEW_SMALL_INT(-1);
}
}
STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty) {
self->duty = duty;
self->duty_mode = DUTY_U16;
machine_soft_pwm_start(self);
}
STATIC mp_obj_t mp_machine_pwm_duty_get_ns(machine_pwm_obj_t *self) {
if (self->duty_mode == DUTY_NS) {
return MP_OBJ_NEW_SMALL_INT(self->duty);
} else {
return MP_OBJ_NEW_SMALL_INT(-1);
}
}
STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty) {
self->duty = duty;
self->duty_mode = DUTY_NS;
machine_soft_pwm_start(self);
}
/* Interface for the implementation */
STATIC void machine_soft_pwm_start(machine_pwm_obj_t *self) {
// check if ready to go
if (self->defer_start == true || self->freq == 0 || self->duty_mode == DUTY_NOT_SET) {
return; // Not ready yet.
}
int ret = pwm_set_period_us(SOFT_PWM_BASE_FREQ / self->freq);
if (ret >= 0) {
int duty_width;
if (self->duty_mode == DUTY) {
duty_width = self->duty * DUTY_FULL_SCALE / 100;
} else if (self->duty_mode == DUTY_U16) {
duty_width = self->duty * DUTY_FULL_SCALE / 65536;
}if (self->duty_mode == DUTY_NS) {
duty_width = (uint64_t)self->duty * self->freq * DUTY_FULL_SCALE / 1000000000ULL;
}
pwm_set_duty_cycle(self->pwm_pin, duty_width);
}
}
#endif // MICROPY_PY_MACHINE_HW_PWM