mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-04-01 09:00:18 +02:00
86 lines
3.1 KiB
C
86 lines
3.1 KiB
C
/**
|
|
* @file pwm.c
|
|
* @brief Implementation of the generic PWM output driver
|
|
* @author Kevin Thomas
|
|
* @date 2025
|
|
*
|
|
* MIT License
|
|
*
|
|
* Copyright (c) 2025 Kevin Thomas
|
|
*
|
|
* 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 "pwm.h"
|
|
#include "pico/stdlib.h"
|
|
#include "hardware/pwm.h"
|
|
#include "hardware/clocks.h"
|
|
|
|
static uint pwm_slice;
|
|
static uint pwm_chan;
|
|
static uint32_t pwm_wrap;
|
|
|
|
/**
|
|
* @brief Compute the PWM clock divider that yields the target frequency
|
|
*
|
|
* Derives a floating-point divider from the current system clock frequency,
|
|
* the desired output frequency, and the chosen wrap value so that the PWM
|
|
* counter overflows exactly freq_hz times per second.
|
|
*
|
|
* @param freq_hz Desired PWM output frequency in Hz
|
|
* @param wrap_val Chosen PWM counter wrap value (period - 1)
|
|
* @return float Clock divider to program into the PWM slice
|
|
*/
|
|
static float _calc_clk_div(uint32_t freq_hz, uint32_t wrap_val) {
|
|
uint32_t sys_hz = clock_get_hz(clk_sys);
|
|
return (float)sys_hz / ((float)freq_hz * (float)(wrap_val + 1));
|
|
}
|
|
|
|
/**
|
|
* @brief Apply the PWM configuration to the active slice
|
|
*
|
|
* Builds a default config, sets the clock divider for the target frequency,
|
|
* programs the wrap value, starts the slice, and zeroes the channel level.
|
|
*
|
|
* @param freq_hz Desired PWM output frequency in Hz
|
|
*/
|
|
static void _apply_pwm_config(uint32_t freq_hz) {
|
|
pwm_config cfg = pwm_get_default_config();
|
|
pwm_config_set_clkdiv(&cfg, _calc_clk_div(freq_hz, pwm_wrap));
|
|
pwm_config_set_wrap(&cfg, pwm_wrap);
|
|
pwm_init(pwm_slice, &cfg, true);
|
|
pwm_set_chan_level(pwm_slice, pwm_chan, 0);
|
|
}
|
|
|
|
void pwm_driver_init(uint32_t pin, uint32_t freq_hz) {
|
|
gpio_set_function(pin, GPIO_FUNC_PWM);
|
|
pwm_slice = pwm_gpio_to_slice_num(pin);
|
|
pwm_chan = pwm_gpio_to_channel(pin);
|
|
pwm_wrap = 10000 - 1;
|
|
_apply_pwm_config(freq_hz);
|
|
}
|
|
|
|
void pwm_driver_set_duty_percent(uint8_t percent) {
|
|
if (percent > 100) {
|
|
percent = 100;
|
|
}
|
|
uint32_t level = ((uint32_t)percent * (pwm_wrap + 1)) / 100;
|
|
pwm_set_chan_level(pwm_slice, pwm_chan, level);
|
|
}
|