mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-05-21 15:16:57 +02:00
Kevin Thomas
116 lines
3.2 KiB
C
116 lines
3.2 KiB
C
/**
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* @file main.c
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* @brief PWM demonstration: LED breathing effect via duty-cycle sweep.
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* @author Kevin Thomas
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* @date 2026
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*
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* Demonstrates PWM output using the PWM driver. A signal on
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* GPIO 25 (onboard LED) sweeps its duty cycle from 0% to 100%
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* and back to produce a smooth breathing effect. The current
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* duty is reported over UART.
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*
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* Wiring:
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* GPIO0 -> UART TX (USB-to-UART adapter RX)
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* GPIO1 -> UART RX (USB-to-UART adapter TX)
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* GPIO25 -> Onboard LED (no external wiring needed)
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*
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* MIT License
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*
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* Copyright (c) 2026 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 "rp2350_pwm.h"
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#include "rp2350_uart.h"
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#include "rp2350_delay.h"
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/** @brief PWM duty cycle increment per step */
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#define SWEEP_STEP 5
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/** @brief Delay between PWM sweep steps in milliseconds */
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#define SWEEP_DELAY_MS 50
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/**
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* @brief Convert a uint8_t to a decimal string.
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* @param value number to convert (0-255)
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* @param buf output buffer (at least 4 bytes)
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* @retval None
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*/
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static void uint8_to_str(uint8_t value, char *buf)
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{
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uint8_t idx = 0;
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if (value >= 100)
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buf[idx++] = (char)('0' + value / 100);
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if (value >= 10)
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buf[idx++] = (char)('0' + (value / 10) % 10);
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buf[idx++] = (char)('0' + value % 10);
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buf[idx] = '\0';
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}
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/**
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* @brief Print a duty percentage value as a decimal string over UART.
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* @param duty duty cycle value (0-100)
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* @retval None
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*/
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static void print_duty(uint8_t duty)
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{
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char buf[4];
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uint8_to_str(duty, buf);
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uart_puts("Duty: ");
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uart_puts(buf);
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uart_puts("%\r\n");
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}
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/**
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* @brief Sweep duty cycle upward from 0 to 100 percent.
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* @retval None
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*/
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static void sweep_up(void)
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{
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for (uint8_t duty = 0; duty <= 100; duty += SWEEP_STEP)
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{
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pwm_set_duty(duty);
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print_duty(duty);
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delay_ms(SWEEP_DELAY_MS);
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}
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}
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/**
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* @brief Sweep duty cycle downward from 100 to 0 percent.
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* @retval None
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*/
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static void sweep_down(void)
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{
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for (int8_t duty = 100; duty >= 0; duty -= SWEEP_STEP)
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{
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pwm_set_duty((uint8_t)duty);
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print_duty((uint8_t)duty);
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delay_ms(SWEEP_DELAY_MS);
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}
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}
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int main(void)
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{
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uart_puts("PWM initialized: GPIO25\r\n");
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while (1)
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{
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sweep_up();
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sweep_down();
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}
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}
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