259 lines
7.5 KiB
C
259 lines
7.5 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) 2016 Mark Shannon
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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/mphal.h"
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#if MICROPY_PY_MACHINE_SOFT_PWM
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#include "stddef.h"
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#include "py/runtime.h"
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#include "py/gc.h"
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#include "nrf_timer.h"
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#include "nrf_gpio.h"
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#include "pin.h"
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#include "ticker.h"
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#define CYCLES_PER_MICROSECONDS 16
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#define MICROSECONDS_PER_TICK 16
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#define CYCLES_PER_TICK (CYCLES_PER_MICROSECONDS*MICROSECONDS_PER_TICK)
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// This must be an integer multiple of MICROSECONDS_PER_TICK
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#define MICROSECONDS_PER_MACRO_TICK 6000
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#define MILLISECONDS_PER_MACRO_TICK 6
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#define PWM_TICKER_INDEX 2
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// Default period of 20ms
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#define DEFAULT_PERIOD ((20*1000)/MICROSECONDS_PER_TICK)
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typedef struct _pwm_event {
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uint16_t time;
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uint8_t pin;
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uint8_t turn_on;
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} pwm_event;
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typedef struct _pwm_events {
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uint8_t count;
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uint16_t period;
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uint32_t all_pins;
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pwm_event events[1];
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} pwm_events;
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static const pwm_events OFF_EVENTS = {
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.count = 1,
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.period = DEFAULT_PERIOD,
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.all_pins = 0,
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.events = {
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{
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.time = 1024,
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.pin = 31,
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.turn_on = 0
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}
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}
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};
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#define active_events MP_STATE_PORT(pwm_active_events)
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#define pending_events MP_STATE_PORT(pwm_pending_events)
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void softpwm_init0(void) {
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active_events = &OFF_EVENTS;
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pending_events = NULL;
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}
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static uint8_t next_event = 0;
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static inline int32_t pwm_get_period_ticks(void) {
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const pwm_events *tmp = pending_events;
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if (tmp == NULL)
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tmp = active_events;
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return tmp->period;
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}
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#if 0
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void pwm_dump_events(const pwm_events *events) {
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printf("Count %d, period %d, all pins %d\r\n", events->count, events->period, events->all_pins);
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for (uint32_t i = 0; i < events->count; i++) {
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const pwm_event *event = &events->events[i];
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printf("Event. pin: %d, duty cycle: %d, turn_on: %d\r\n",
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event->pin, event->time, event->turn_on);
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}
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}
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void pwm_dump_state(void) {
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while(pending_events);
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pwm_dump_events(active_events);
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}
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#endif
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static const pwm_events *swap_pending(const pwm_events *in) {
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__disable_irq();
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const pwm_events *result = pending_events;
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pending_events = in;
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__enable_irq();
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return result;
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}
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static pwm_events *copy_events(const pwm_events *orig, uint32_t count) {
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pwm_events *events = m_malloc(sizeof(pwm_events) + (count-1)*sizeof(pwm_event));
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events->count = count;
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uint32_t copy = count > orig->count ? orig->count : count;
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for (uint32_t i = 0; i < copy; i++) {
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events->events[i] = orig->events[i];
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}
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return events;
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}
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static int find_pin_in_events(const pwm_events *events, uint32_t pin) {
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for (int i = 0; i < events->count; i++) {
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if (events->events[i].pin == pin)
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return i;
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}
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return -1;
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}
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static void sort_events(pwm_events *events) {
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// Insertion sort
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for (int32_t i = 1; i < events->count; i++) {
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pwm_event x = events->events[i];
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int32_t j;
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for (j = i - 1; j >= 0 && events->events[j].time > x.time; j--) {
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events->events[j+1] = events->events[j];
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}
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events->events[j+1] = x;
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}
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}
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int32_t pwm_callback(void) {
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int32_t tdiff;
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const pwm_events *events = active_events;
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const pwm_event *event = &events->events[next_event];
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int32_t tnow = (event->time*events->period)>>10;
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do {
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if (event->turn_on) {
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nrf_gpio_pin_set(event->pin);
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next_event++;
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} else {
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// TODO: Resolve port for nrf52
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nrf_gpio_port_out_clear(NRF_GPIO, events->all_pins);
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next_event = 0;
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tnow = 0;
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if (pending_events) {
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events = pending_events;
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active_events = events;
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pending_events = NULL;
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}
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}
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event = &events->events[next_event];
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tdiff = ((event->time*events->period)>>10) - tnow;
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} while (tdiff == 0);
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return tdiff;
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}
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void pwm_start(void) {
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set_ticker_callback(PWM_TICKER_INDEX, pwm_callback, 120);
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}
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void pwm_stop(void) {
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clear_ticker_callback(PWM_TICKER_INDEX);
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}
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static void pwm_set_period_ticks(int32_t ticks) {
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const pwm_events *old_events = swap_pending(NULL);
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if (old_events == NULL) {
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old_events = active_events;
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}
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pwm_events *events = copy_events(old_events, old_events->count);
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events->all_pins = old_events->all_pins;
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events->period = ticks;
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pending_events = events;
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}
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int pwm_set_period_us(int32_t us) {
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if ((us < 256) ||
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(us > 1000000)) {
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return -1;
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}
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pwm_set_period_ticks(us/MICROSECONDS_PER_TICK);
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return 0;
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}
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int32_t pwm_get_period_us(void) {
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return pwm_get_period_ticks()*MICROSECONDS_PER_TICK;
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}
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void pwm_set_duty_cycle(int32_t pin, uint32_t value) {
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if (value >= (1<<10)) {
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value = (1<<10)-1;
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}
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uint32_t turn_on_time = 1024-value;
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const pwm_events *old_events = swap_pending(NULL);
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if (old_events == NULL) {
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old_events = active_events;
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}
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if (((1<<pin)&old_events->all_pins) == 0) {
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nrf_gpio_cfg_output(pin);
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}
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int ev = find_pin_in_events(old_events, pin);
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pwm_events *events;
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if (ev < 0 && value == 0) {
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return;
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} else if (ev < 0) {
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events = copy_events(old_events, old_events->count+1);
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events->all_pins = old_events->all_pins | (1<<pin);
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events->events[old_events->count].time = turn_on_time;
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events->events[old_events->count].pin = pin;
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events->events[old_events->count].turn_on = 1;
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} else if (value == 0) {
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events = copy_events(old_events, old_events->count-1);
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events->all_pins = old_events->all_pins & ~(1<<pin);
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if (ev < old_events->count-1) {
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events->events[ev] = old_events->events[old_events->count-1];
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}
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} else {
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events = copy_events(old_events, old_events->count);
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events->all_pins = old_events->all_pins;
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events->events[ev].time = turn_on_time;
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}
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events->period = old_events->period;
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sort_events(events);
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pending_events = events;
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return;
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}
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void pwm_release(int32_t pin) {
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pwm_set_duty_cycle(pin, 0);
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const pwm_events *ev = active_events;
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int i = find_pin_in_events(ev, pin);
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if (i < 0)
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return;
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// If i >= 0 it means that `ev` is in RAM, so it safe to discard the const qualifier
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((pwm_events *)ev)->events[i].pin = 31;
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nrf_gpio_pin_clear(pin);
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}
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#endif // MICROPY_PY_MACHINE_SOFT_PWM
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