mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-06-06 06:13:59 +02:00
Kevin Thomas
108f3f5598
- Single-wire protocol on GPIO4 via SIO register bit-bang - TIMER0 TIMERAWL for microsecond pulse-width measurement - Tick generator configured for 1 us ticks at 12 MHz clk_ref - UART output: humidity/temperature or wiring failure message - Zero warnings, 1876 bytes text
111 lines
3.0 KiB
C
111 lines
3.0 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 DHT11 temperature and humidity sensor demonstration.
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*
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* Reads the DHT11 sensor on GPIO4 every 2 seconds, printing
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* humidity and temperature over UART. Reports read failures
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* for wiring diagnostics.
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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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* GPIO4 -> DHT11 DATA (10k pull-up to 3.3V recommended)
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* 3.3V -> DHT11 VCC
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* GND -> DHT11 GND
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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_dht11.h"
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#include "rp2350_uart.h"
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#include "rp2350_delay.h"
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#include "rp2350_xosc.h"
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/**
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* @brief Minimum polling interval for the DHT11 sensor in milliseconds.
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*/
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#define DHT11_POLL_MS 2000U
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/**
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* @brief Convert an unsigned integer (0-255) to a decimal string.
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* @param value number to convert
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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 _uint_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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buf[idx++] = (char)('0' + (value / 10) % 10);
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buf[idx++] = (char)('0' + value % 10);
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} else if (value >= 10) {
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buf[idx++] = (char)('0' + value / 10);
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buf[idx++] = (char)('0' + value % 10);
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} else {
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buf[idx++] = (char)('0' + value);
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}
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buf[idx] = '\0';
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}
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/**
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* @brief Print a successful DHT11 reading over UART.
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* @param humidity humidity percentage (integer)
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* @param temperature temperature in Celsius (integer)
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* @retval None
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*/
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static void _print_reading(uint8_t humidity, uint8_t temperature)
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{
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char buf[4];
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uart_puts("Humidity: ");
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_uint_to_str(humidity, buf);
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uart_puts(buf);
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uart_puts("% Temperature: ");
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_uint_to_str(temperature, buf);
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uart_puts(buf);
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uart_puts(" C\r\n");
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}
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/**
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* @brief Print a read failure message over UART.
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* @retval None
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*/
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static void _print_failure(void)
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{
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uart_puts("DHT11 read failed - check wiring on GPIO4\r\n");
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}
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/**
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* @brief Application entry point for the DHT11 sensor 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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uint8_t humidity;
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uint8_t temperature;
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xosc_set_clk_ref();
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dht11_timer_release_reset();
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dht11_timer_start_tick();
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dht11_init();
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uart_puts("DHT11 driver initialized on GPIO4\r\n");
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while (1) {
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if (dht11_read(&humidity, &temperature))
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_print_reading(humidity, temperature);
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else
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_print_failure();
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delay_ms(DHT11_POLL_MS);
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}
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}
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