mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-05-30 02:59:30 +02:00
Kevin Thomas
f560e40cf7
- PWM slice 4, channel B on GPIO25 (onboard LED) - Duty cycle sweep 0-100% in 5% steps for breathing effect - Wrap 9999 with no clock division (~650 Hz from ROSC) - UART reports each duty step - 1390B FLASH, 11 source files, zero warnings
100 lines
2.5 KiB
C
100 lines
2.5 KiB
C
/**
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******************************************************************************
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* @file main.c
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* @author Kevin Thomas
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* @brief PWM demonstration: LED breathing effect via duty-cycle sweep.
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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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******************************************************************************
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* @attention
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*
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* Copyright (c) 2026 Kevin Thomas.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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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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#define SWEEP_STEP 5
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#define SWEEP_DELAY_MS 50
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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_t idx = 0;
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if (duty >= 100) {
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buf[idx++] = '1';
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buf[idx++] = '0';
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buf[idx++] = '0';
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} else if (duty >= 10) {
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buf[idx++] = (char)('0' + duty / 10);
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buf[idx++] = (char)('0' + duty % 10);
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} else {
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buf[idx++] = (char)('0' + duty);
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}
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buf[idx] = '\0';
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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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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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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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/**
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* @brief Application entry point for the PWM LED breathing demo.
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* @retval int does not return
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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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_sweep_up();
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_sweep_down();
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}
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}
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