286 lines
11 KiB
C
286 lines
11 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2020-2021 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/runtime.h"
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#include "py/mphal.h"
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#include "modmachine.h"
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#include "hardware/clocks.h"
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#include "hardware/pwm.h"
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/******************************************************************************/
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// MicroPython bindings for machine.PWM
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typedef struct _machine_pwm_obj_t {
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mp_obj_base_t base;
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uint8_t slice;
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uint8_t channel;
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uint8_t invert;
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uint8_t duty_type;
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mp_int_t duty;
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} machine_pwm_obj_t;
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enum {
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VALUE_NOT_SET = -1,
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DUTY_NOT_SET = 0,
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DUTY_U16,
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DUTY_NS
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};
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STATIC machine_pwm_obj_t machine_pwm_obj[] = {
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{{&machine_pwm_type}, 0, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 0, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 1, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 1, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 2, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 2, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 3, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 3, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 4, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 4, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 5, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 5, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 6, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 6, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 7, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 },
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{{&machine_pwm_type}, 7, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 },
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};
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STATIC bool defer_start;
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STATIC bool slice_freq_set[8];
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STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq);
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STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16);
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STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns);
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STATIC void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
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machine_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in);
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mp_printf(print, "<PWM slice=%u channel=%u invert=%u>",
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self->slice, self->channel, self->invert);
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}
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void machine_pwm_start(machine_pwm_obj_t *self) {
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// Start the PWM if properly set.
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if (defer_start == false && slice_freq_set[self->slice] == true && self->duty_type != DUTY_NOT_SET) {
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if (self->channel == PWM_CHAN_A) {
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pwm_set_output_polarity(self->slice, self->invert, (self + 1)->invert);
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} else {
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pwm_set_output_polarity(self->slice, (self - 1)->invert, self->invert);
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}
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pwm_set_enabled(self->slice, true);
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}
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}
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STATIC void mp_machine_pwm_init_helper(machine_pwm_obj_t *self,
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size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
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enum { ARG_freq, ARG_duty_u16, ARG_duty_ns, ARG_invert };
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static const mp_arg_t allowed_args[] = {
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{ MP_QSTR_freq, MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
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{ MP_QSTR_duty_u16, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
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{ MP_QSTR_duty_ns, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
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{ MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} },
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};
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// Parse the arguments.
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mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
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mp_arg_parse_all(n_args, pos_args, kw_args,
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MP_ARRAY_SIZE(allowed_args), allowed_args, args);
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// defer starting PWM until all provided args are checked.
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defer_start = true;
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if (args[ARG_freq].u_int != VALUE_NOT_SET) {
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mp_machine_pwm_freq_set(self, args[ARG_freq].u_int);
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}
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if (args[ARG_duty_u16].u_int != VALUE_NOT_SET) {
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mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int);
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}
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if (args[ARG_duty_ns].u_int != VALUE_NOT_SET) {
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mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int);
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}
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if (args[ARG_invert].u_int != VALUE_NOT_SET) {
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self->invert = !!args[ARG_invert].u_int;
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}
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defer_start = false;
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machine_pwm_start(self);
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}
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// PWM(pin [, args])
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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 *all_args) {
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// Check number of arguments
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mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
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// Get GPIO to connect to PWM.
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uint32_t gpio = mp_hal_get_pin_obj(all_args[0]);
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// Get static peripheral object.
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uint slice = pwm_gpio_to_slice_num(gpio);
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uint8_t channel = pwm_gpio_to_channel(gpio);
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machine_pwm_obj_t *self = &machine_pwm_obj[slice * 2 + channel];
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self->invert = 0;
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self->duty_type = DUTY_NOT_SET;
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// Select PWM function for given GPIO.
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gpio_set_function(gpio, GPIO_FUNC_PWM);
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// Process the remaining parameters.
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mp_map_t kw_args;
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mp_map_init_fixed_table(&kw_args, n_kw, all_args + n_args);
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mp_machine_pwm_init_helper(self, n_args - 1, all_args + 1, &kw_args);
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return MP_OBJ_FROM_PTR(self);
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}
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// Stop all active slices.
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void machine_pwm_deinit_all(void) {
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for (int i = 0; i < 8; i++) {
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slice_freq_set[i] = false;
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pwm_set_enabled(machine_pwm_obj[i].slice, false);
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}
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}
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STATIC void mp_machine_pwm_deinit(machine_pwm_obj_t *self) {
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pwm_set_enabled(self->slice, false);
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}
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// Returns: floor((16*F + offset) / div16)
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// Avoids overflow in the numerator that would occur if
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// 16*F + offset > 2**32
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// F + offset/16 > 2**28 = 268435456 (approximately, due to flooring)
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uint32_t get_slice_hz(uint32_t offset, uint32_t div16) {
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uint32_t source_hz = clock_get_hz(clk_sys);
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if (source_hz + offset / 16 > 268000000) {
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return (16 * (uint64_t)source_hz + offset) / div16;
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} else {
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return (16 * source_hz + offset) / div16;
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}
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}
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// Returns 16*F / denom, rounded.
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uint32_t get_slice_hz_round(uint32_t div16) {
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return get_slice_hz(div16 / 2, div16);
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}
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// Returns ceil(16*F / denom).
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uint32_t get_slice_hz_ceil(uint32_t div16) {
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return get_slice_hz(div16 - 1, div16);
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}
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STATIC mp_obj_t mp_machine_pwm_freq_get(machine_pwm_obj_t *self) {
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uint32_t div16 = pwm_hw->slice[self->slice].div;
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uint32_t top = pwm_hw->slice[self->slice].top;
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uint32_t pwm_freq = get_slice_hz_round(div16 * (top + 1));
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return MP_OBJ_NEW_SMALL_INT(pwm_freq);
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}
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STATIC void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) {
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// Set the frequency, making "top" as large as possible for maximum resolution.
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// Maximum "top" is set at 65534 to be able to achieve 100% duty with 65535.
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#define TOP_MAX 65534
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uint32_t source_hz = clock_get_hz(clk_sys);
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uint32_t div16;
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uint32_t top;
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if ((source_hz + freq / 2) / freq < TOP_MAX) {
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// If possible (based on the formula for TOP below), use a DIV of 1.
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// This also prevents overflow in the DIV calculation.
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div16 = 16;
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// Same as get_slice_hz_round() below but canceling the 16s
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// to avoid overflow for high freq.
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top = (source_hz + freq / 2) / freq - 1;
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} else {
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// Otherwise, choose the smallest possible DIV for maximum
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// duty cycle resolution.
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// Constraint: 16*F/(div16*freq) < TOP_MAX
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// So:
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div16 = get_slice_hz_ceil(TOP_MAX * freq);
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// Set TOP as accurately as possible using rounding.
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top = get_slice_hz_round(div16 * freq) - 1;
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}
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if (div16 < 16) {
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mp_raise_ValueError(MP_ERROR_TEXT("freq too large"));
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} else if (div16 >= 256 * 16) {
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mp_raise_ValueError(MP_ERROR_TEXT("freq too small"));
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}
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pwm_hw->slice[self->slice].div = div16;
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pwm_hw->slice[self->slice].top = top;
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slice_freq_set[self->slice] = true;
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if (self->duty_type == DUTY_U16) {
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mp_machine_pwm_duty_set_u16(self, self->duty);
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} else if (self->duty_type == DUTY_NS) {
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mp_machine_pwm_duty_set_ns(self, self->duty);
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}
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machine_pwm_obj_t *other = self->channel == PWM_CHAN_A ? self + 1 : self - 1;
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if (other->duty_type == DUTY_U16) {
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mp_machine_pwm_duty_set_u16(other, other->duty);
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} else if (other->duty_type == DUTY_NS) {
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mp_machine_pwm_duty_set_ns(other, other->duty);
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}
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}
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STATIC mp_obj_t mp_machine_pwm_duty_get_u16(machine_pwm_obj_t *self) {
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uint32_t top = pwm_hw->slice[self->slice].top;
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uint32_t cc = pwm_hw->slice[self->slice].cc;
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cc = (cc >> (self->channel ? PWM_CH0_CC_B_LSB : PWM_CH0_CC_A_LSB)) & 0xffff;
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// Use rounding (instead of flooring) here to give as accurate an
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// estimate as possible.
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return MP_OBJ_NEW_SMALL_INT((cc * 65535 + (top + 1) / 2) / (top + 1));
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}
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STATIC void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16) {
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uint32_t top = pwm_hw->slice[self->slice].top;
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// Use rounding here to set it as accurately as possible.
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uint32_t cc = (duty_u16 * (top + 1) + 65535 / 2) / 65535;
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pwm_set_chan_level(self->slice, self->channel, cc);
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self->duty = duty_u16;
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self->duty_type = DUTY_U16;
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machine_pwm_start(self);
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}
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STATIC mp_obj_t mp_machine_pwm_duty_get_ns(machine_pwm_obj_t *self) {
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uint32_t slice_hz = get_slice_hz_round(pwm_hw->slice[self->slice].div);
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uint32_t cc = pwm_hw->slice[self->slice].cc;
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cc = (cc >> (self->channel ? PWM_CH0_CC_B_LSB : PWM_CH0_CC_A_LSB)) & 0xffff;
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return MP_OBJ_NEW_SMALL_INT(((uint64_t)cc * 1000000000ULL + slice_hz / 2) / slice_hz);
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}
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STATIC void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns) {
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uint32_t slice_hz = get_slice_hz_round(pwm_hw->slice[self->slice].div);
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uint32_t cc = ((uint64_t)duty_ns * slice_hz + 500000000ULL) / 1000000000ULL;
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if (cc > 65535) {
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mp_raise_ValueError(MP_ERROR_TEXT("duty larger than period"));
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}
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pwm_set_chan_level(self->slice, self->channel, cc);
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self->duty = duty_ns;
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self->duty_type = DUTY_NS;
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machine_pwm_start(self);
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}
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