circuitpython/ports/espressif/common-hal/pwmio/PWMOut.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
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* Copyright (c) 2020 Lucian Copeland for Adafruit Industries
*
* 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.
*/
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#include <math.h>
#include "common-hal/pwmio/PWMOut.h"
#include "shared-bindings/pwmio/PWMOut.h"
#include "py/runtime.h"
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#include "components/driver/include/driver/ledc.h"
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#define INDEX_EMPTY 0xFF
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STATIC uint32_t reserved_timer_freq[LEDC_TIMER_MAX];
STATIC bool varfreq_timers[LEDC_TIMER_MAX];
STATIC uint8_t reserved_channels[LEDC_CHANNEL_MAX] = { [0 ... LEDC_CHANNEL_MAX - 1] = INDEX_EMPTY};
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STATIC bool never_reset_tim[LEDC_TIMER_MAX];
STATIC bool never_reset_chan[LEDC_CHANNEL_MAX];
STATIC uint32_t calculate_duty_cycle(uint32_t frequency) {
uint32_t duty_bits = 0;
uint32_t interval = LEDC_APB_CLK_HZ / frequency;
for (size_t i = 0; i < 32; i++) {
if (!(interval >> i)) {
duty_bits = i - 1;
break;
}
}
if (duty_bits >= LEDC_TIMER_14_BIT) {
duty_bits = LEDC_TIMER_13_BIT;
}
return duty_bits;
}
void pwmout_reset(void) {
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for (size_t i = 0; i < LEDC_CHANNEL_MAX; i++) {
if (reserved_channels[i] != INDEX_EMPTY) {
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ledc_stop(LEDC_LOW_SPEED_MODE, i, 0);
}
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if (!never_reset_chan[i]) {
reserved_channels[i] = INDEX_EMPTY;
}
}
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for (size_t i = 0; i < LEDC_TIMER_MAX; i++) {
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if (reserved_timer_freq[i]) {
ledc_timer_rst(LEDC_LOW_SPEED_MODE, i);
}
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if (!never_reset_tim[i]) {
reserved_timer_freq[i] = 0;
varfreq_timers[i] = false;
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}
}
}
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pwmout_result_t common_hal_pwmio_pwmout_construct(pwmio_pwmout_obj_t *self,
const mcu_pin_obj_t *pin,
uint16_t duty,
uint32_t frequency,
bool variable_frequency) {
// check the frequency (avoid divide by zero below)
if (frequency == 0) {
return PWMOUT_INVALID_FREQUENCY;
}
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// Calculate duty cycle
uint32_t duty_bits = calculate_duty_cycle(frequency);
if (duty_bits == 0) {
return PWMOUT_INVALID_FREQUENCY;
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}
// Find a viable timer
size_t timer_index = INDEX_EMPTY;
size_t channel_index = INDEX_EMPTY;
for (size_t i = 0; i < LEDC_TIMER_MAX; i++) {
// accept matching freq timers unless this instance is varfreq or a prior one was
if ((reserved_timer_freq[i] == frequency) && !variable_frequency && !varfreq_timers[i]) {
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// prioritize matched frequencies so we don't needlessly take slots
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timer_index = i;
break;
} else if (reserved_timer_freq[i] == 0) {
timer_index = i;
break;
}
}
if (timer_index == INDEX_EMPTY) {
// Running out of timers isn't pin related on ESP32S2.
return PWMOUT_ALL_TIMERS_IN_USE;
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}
// Find a viable channel
for (size_t i = 0; i < LEDC_CHANNEL_MAX; i++) {
if (reserved_channels[i] == INDEX_EMPTY) {
channel_index = i;
break;
}
}
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if (channel_index == INDEX_EMPTY) {
return PWMOUT_ALL_CHANNELS_IN_USE;
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}
// Run configuration
self->tim_handle.timer_num = timer_index;
self->tim_handle.duty_resolution = duty_bits;
self->tim_handle.freq_hz = frequency;
self->tim_handle.speed_mode = LEDC_LOW_SPEED_MODE;
self->tim_handle.clk_cfg = LEDC_AUTO_CLK;
if (ledc_timer_config(&(self->tim_handle)) != ESP_OK) {
return PWMOUT_INITIALIZATION_ERROR;
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}
self->chan_handle.channel = channel_index;
self->chan_handle.duty = duty >> (16 - duty_bits);
self->chan_handle.gpio_num = pin->number;
self->chan_handle.speed_mode = LEDC_LOW_SPEED_MODE; // Only LS is allowed on ESP32-S2
self->chan_handle.hpoint = 0;
self->chan_handle.timer_sel = timer_index;
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if (ledc_channel_config(&(self->chan_handle))) {
return PWMOUT_INITIALIZATION_ERROR;
}
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// Make reservations
reserved_timer_freq[timer_index] = frequency;
reserved_channels[channel_index] = timer_index;
if (variable_frequency) {
varfreq_timers[timer_index] = true;
}
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self->variable_frequency = variable_frequency;
self->pin = pin;
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self->deinited = false;
self->duty_resolution = duty_bits;
claim_pin(pin);
// Set initial duty
common_hal_pwmio_pwmout_set_duty_cycle(self, duty);
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return PWMOUT_OK;
}
void common_hal_pwmio_pwmout_never_reset(pwmio_pwmout_obj_t *self) {
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never_reset_tim[self->tim_handle.timer_num] = true;
never_reset_chan[self->chan_handle.channel] = true;
never_reset_pin_number(self->pin->number);
}
void common_hal_pwmio_pwmout_reset_ok(pwmio_pwmout_obj_t *self) {
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never_reset_tim[self->tim_handle.timer_num] = false;
never_reset_chan[self->chan_handle.channel] = false;
}
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bool common_hal_pwmio_pwmout_deinited(pwmio_pwmout_obj_t *self) {
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return self->deinited == true;
}
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void common_hal_pwmio_pwmout_deinit(pwmio_pwmout_obj_t *self) {
if (common_hal_pwmio_pwmout_deinited(self)) {
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return;
}
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if (reserved_channels[self->chan_handle.channel] != INDEX_EMPTY) {
ledc_stop(LEDC_LOW_SPEED_MODE, self->chan_handle.channel, 0);
}
reserved_channels[self->chan_handle.channel] = INDEX_EMPTY;
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// Search if any other channel is using the timer
bool taken = false;
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for (size_t i = 0; i < LEDC_CHANNEL_MAX; i++) {
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if (reserved_channels[i] == self->tim_handle.timer_num) {
taken = true;
}
}
// Variable frequency means there's only one channel on the timer
if (!taken || self->variable_frequency) {
ledc_timer_rst(LEDC_LOW_SPEED_MODE, self->tim_handle.timer_num);
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reserved_timer_freq[self->tim_handle.timer_num] = 0;
// if timer isn't varfreq this will be off aleady
varfreq_timers[self->tim_handle.timer_num] = false;
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}
common_hal_reset_pin(self->pin);
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self->deinited = true;
}
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void common_hal_pwmio_pwmout_set_duty_cycle(pwmio_pwmout_obj_t *self, uint16_t duty) {
ledc_set_duty(LEDC_LOW_SPEED_MODE, self->chan_handle.channel, duty >> (16 - self->duty_resolution));
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ledc_update_duty(LEDC_LOW_SPEED_MODE, self->chan_handle.channel);
}
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uint16_t common_hal_pwmio_pwmout_get_duty_cycle(pwmio_pwmout_obj_t *self) {
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return ledc_get_duty(LEDC_LOW_SPEED_MODE, self->chan_handle.channel) << (16 - self->duty_resolution);
}
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void common_hal_pwmio_pwmout_set_frequency(pwmio_pwmout_obj_t *self, uint32_t frequency) {
// Calculate duty cycle
uint32_t duty_bits = calculate_duty_cycle(frequency);
if (duty_bits == 0) {
mp_arg_error_invalid(MP_QSTR_frequency);
}
self->duty_resolution = duty_bits;
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ledc_set_freq(LEDC_LOW_SPEED_MODE, self->tim_handle.timer_num, frequency);
}
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uint32_t common_hal_pwmio_pwmout_get_frequency(pwmio_pwmout_obj_t *self) {
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return ledc_get_freq(LEDC_LOW_SPEED_MODE, self->tim_handle.timer_num);
}
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bool common_hal_pwmio_pwmout_get_variable_frequency(pwmio_pwmout_obj_t *self) {
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return self->variable_frequency;
}
const mcu_pin_obj_t *common_hal_pwmio_pwmout_get_pin(pwmio_pwmout_obj_t *self) {
return self->pin;
}