Add 0x03_button_cbm: bare-metal RP2350 button driver

- GPIO15 active-low button input with internal pull-up - 20ms software debounce via busy-wait confirmation - LED mirrors button state, UART reports edge transitions - New gpio_config_input_pullup() in GPIO driver - 1555B FLASH, 13 source files, zero warnings
2026-08-31 07:10:55 +02:00 · 2026-04-05 16:06:46 -04:00
parent d072ec5946
commit afdc1fa594
33 changed files with 2313 additions and 0 deletions
@@ -0,0 +1,94 @@
+/**
+  ******************************************************************************
+  * @file    main.c
+  * @author  Kevin Thomas
+  * @brief   Button demonstration: debounced press mirrors to LED + UART report.
+  *
+  *          Demonstrates GPIO input using the button driver. The onboard
+  *          LED mirrors the button state and every edge transition is
+  *          reported over UART.
+  *
+  *          Wiring:
+  *            GPIO15 -> One leg of push button
+  *            GND    -> Other leg of push button
+  *            GPIO25 -> Onboard LED (no external wiring needed)
+  *
+  ******************************************************************************
+  * @attention
+  *
+  * Copyright (c) 2026 Kevin Thomas.
+  * All rights reserved.
+  *
+  * This software is licensed under terms that can be found in the LICENSE file
+  * in the root directory of this software component.
+  * If no LICENSE file comes with this software, it is provided AS-IS.
+  *
+  ******************************************************************************
+  */
+
+#include "rp2350_button.h"
+#include "rp2350_led.h"
+#include "rp2350_uart.h"
+#include "rp2350_delay.h"
+
+#define DEBOUNCE_MS  20
+#define POLL_DELAY_MS 10
+
+/**
+  * @brief  Drive the LED to match the current button state.
+  * @param  pressed true if button is pressed, false if released
+  * @retval None
+  */
+static void _set_led_state(bool pressed)
+{
+  if (pressed)
+    led_on(LED_PIN);
+  else
+    led_off(LED_PIN);
+}
+
+/**
+  * @brief  Report a button edge transition over UART.
+  * @param  pressed    current button state
+  * @param  last_state pointer to the stored previous button state
+  * @retval None
+  */
+static void _report_edge(bool pressed, bool *last_state)
+{
+  if (pressed != *last_state) {
+    if (pressed)
+      uart_puts("Button: PRESSED\r\n");
+    else
+      uart_puts("Button: RELEASED\r\n");
+    *last_state = pressed;
+  }
+}
+
+/**
+  * @brief  Poll the button, mirror to LED, and report edges.
+  * @param  last_state pointer to the stored previous button state
+  * @retval None
+  */
+static void _poll_button(bool *last_state)
+{
+  bool pressed;
+  pressed = button_is_pressed(BUTTON_PIN);
+  _set_led_state(pressed);
+  _report_edge(pressed, last_state);
+}
+
+/**
+  * @brief  Application entry point for the button debounce demo.
+  * @retval int does not return
+  */
+int main(void)
+{
+  button_init(BUTTON_PIN, DEBOUNCE_MS);
+  led_init(LED_PIN);
+  uart_puts("Button driver initialized: button=GPIO15  led=GPIO25\r\n");
+  bool last_state = false;
+  while (1) {
+    _poll_button(&last_state);
+    delay_ms(POLL_DELAY_MS);
+  }
+}