mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-07-12 23:26:33 +02:00
Kevin Thomas
86 lines
3.0 KiB
C
86 lines
3.0 KiB
C
/**
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* @file 0x0008_uninitialized-variables-c.c
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* @brief Blink LED using direct register-level pad and IO bank configuration
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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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* -----------------------------------------------------------------------------
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*
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* Blinks an LED on GPIO16 using direct register writes to PADS_BANK0 and
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* IO_BANK0 for pad configuration, plus gpioc coprocessor bit-level functions
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* for output enable and data. Demonstrates the register-level equivalent of
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* gpio_init / gpio_set_function.
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*
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* Wiring:
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* GPIO16 -> LED anode (with current-limiting resistor to GND)
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*/
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#include <stdio.h>
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#include "pico/stdlib.h"
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/** @brief GPIO pin number for the LED */
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#define LED_PIN 16
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/**
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* @brief Configure pad and IO bank registers for GPIO16 as SIO output
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*
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* @details Sets PADS_BANK0 IE/OD bits, assigns FUNCSEL to SIO in IO_BANK0,
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* clears the ISO bit, and enables output via the coprocessor.
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*
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* @retval None
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*/
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static void configure_pad_and_iobank(void) {
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gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
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gpioc_bit_out_put(LED_PIN, 0);
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hw_write_masked(&pads_bank0_hw->io[LED_PIN],
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PADS_BANK0_GPIO0_IE_BITS,
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PADS_BANK0_GPIO0_IE_BITS | PADS_BANK0_GPIO0_OD_BITS);
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io_bank0_hw->io[LED_PIN].ctrl = GPIO_FUNC_SIO << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB;
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hw_clear_bits(&pads_bank0_hw->io[LED_PIN], PADS_BANK0_GPIO0_ISO_BITS);
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gpioc_bit_oe_put(LED_PIN, GPIO_OUT);
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}
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/**
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* @brief Blink LED using coprocessor bit output functions
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*
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* @details Toggles the LED on and off with 500ms delays using
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* gpioc_bit_out_put and sleep_us.
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*
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* @retval None
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*/
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static void blink_cycle(void) {
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gpioc_bit_out_put(LED_PIN, 1);
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sleep_us(500 * 1000ull);
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gpioc_bit_out_put(LED_PIN, 0);
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sleep_us(500 * 1000ull);
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}
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int main(void) {
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configure_pad_and_iobank();
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while (true) {
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blink_cycle();
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}
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}
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