mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-06-12 17:17:52 +02:00
Kevin Thomas
c46bcba401
Public function docstrings belong exclusively in .h headers per coding convention. Only static helper functions and static variables retain docstrings in .c files. Removed 413 duplicate docstrings across 185 files (15 CBM + 15 C SDK projects). All 30 projects rebuild with zero errors.
89 lines
3.2 KiB
C
89 lines
3.2 KiB
C
/**
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* @file pwm.c
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* @brief Implementation of the generic PWM output driver
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* @author Kevin Thomas
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* @date 2025
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*
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* MIT License
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*
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* Copyright (c) 2025 Kevin Thomas
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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 all
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* 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 THE
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* SOFTWARE.
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*/
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#include "pwm.h"
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#include "pico/stdlib.h"
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#include "hardware/pwm.h"
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#include "hardware/clocks.h"
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/** @brief PWM hardware slice index */
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static uint pwm_slice;
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/** @brief PWM channel (A or B) within the slice */
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static uint pwm_chan;
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/** @brief PWM counter wrap value */
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static uint32_t pwm_wrap;
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/**
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* @brief Compute the PWM clock divider that yields the target frequency
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*
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* Derives a floating-point divider from the current system clock frequency,
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* the desired output frequency, and the chosen wrap value so that the PWM
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* counter overflows exactly freq_hz times per second.
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*
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* @param freq_hz Desired PWM output frequency in Hz
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* @param wrap_val Chosen PWM counter wrap value (period - 1)
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* @return float Clock divider to program into the PWM slice
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*/
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static float _calc_clk_div(uint32_t freq_hz, uint32_t wrap_val) {
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uint32_t sys_hz = clock_get_hz(clk_sys);
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return (float)sys_hz / ((float)freq_hz * (float)(wrap_val + 1));
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}
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/**
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* @brief Apply the PWM configuration to the active slice
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*
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* Builds a default config, sets the clock divider for the target frequency,
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* programs the wrap value, starts the slice, and zeroes the channel level.
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*
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* @param freq_hz Desired PWM output frequency in Hz
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*/
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static void _apply_pwm_config(uint32_t freq_hz) {
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pwm_config cfg = pwm_get_default_config();
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pwm_config_set_clkdiv(&cfg, _calc_clk_div(freq_hz, pwm_wrap));
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pwm_config_set_wrap(&cfg, pwm_wrap);
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pwm_init(pwm_slice, &cfg, true);
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pwm_set_chan_level(pwm_slice, pwm_chan, 0);
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}
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void pwm_driver_init(uint32_t pin, uint32_t freq_hz) {
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gpio_set_function(pin, GPIO_FUNC_PWM);
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pwm_slice = pwm_gpio_to_slice_num(pin);
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pwm_chan = pwm_gpio_to_channel(pin);
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pwm_wrap = 10000 - 1;
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_apply_pwm_config(freq_hz);
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}
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void pwm_driver_set_duty_percent(uint8_t percent) {
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if (percent > 100) {
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percent = 100;
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}
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uint32_t level = ((uint32_t)percent * (pwm_wrap + 1)) / 100;
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pwm_set_chan_level(pwm_slice, pwm_chan, level);
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}
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