mirror of
https://github.com/mytechnotalent/Embedded-Hacking.git
synced 2026-05-21 23:26:52 +02:00
Kevin Thomas
134 lines
3.7 KiB
C
134 lines
3.7 KiB
C
/**
|
|
* @file main.c
|
|
* @brief DHT11 temperature and humidity sensor demonstration.
|
|
* @author Kevin Thomas
|
|
* @date 2026
|
|
*
|
|
* Reads the DHT11 sensor on GPIO4 every 2 seconds, printing
|
|
* humidity and temperature over UART. Reports read failures
|
|
* for wiring diagnostics.
|
|
*
|
|
* Wiring:
|
|
* GPIO0 -> UART TX (USB-to-UART adapter RX)
|
|
* GPIO1 -> UART RX (USB-to-UART adapter TX)
|
|
* GPIO4 -> DHT11 DATA (10k pull-up to 3.3V recommended)
|
|
* 3.3V -> DHT11 VCC
|
|
* GND -> DHT11 GND
|
|
*
|
|
* MIT License
|
|
*
|
|
* Copyright (c) 2026 Kevin Thomas
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in all
|
|
* copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
* SOFTWARE.
|
|
*/
|
|
#include "rp2350_dht11.h"
|
|
#include "rp2350_uart.h"
|
|
#include "rp2350_delay.h"
|
|
#include "rp2350_xosc.h"
|
|
|
|
/**
|
|
* @brief Minimum polling interval for the DHT11 sensor in milliseconds.
|
|
*/
|
|
/** @brief Interval between DHT11 sensor reads in milliseconds */
|
|
#define DHT11_POLL_MS 2000U
|
|
|
|
/**
|
|
* @brief Convert an unsigned integer (0-255) to a decimal string.
|
|
* @param value number to convert
|
|
* @param buf output buffer (at least 4 bytes)
|
|
* @retval None
|
|
*/
|
|
static void uint_to_str(uint8_t value, char *buf)
|
|
{
|
|
uint8_t idx = 0;
|
|
if (value >= 100)
|
|
buf[idx++] = (char)('0' + value / 100);
|
|
if (value >= 10)
|
|
buf[idx++] = (char)('0' + (value / 10) % 10);
|
|
buf[idx++] = (char)('0' + value % 10);
|
|
buf[idx] = '\0';
|
|
}
|
|
|
|
/**
|
|
* @brief Print a successful DHT11 reading over UART.
|
|
* @param humidity humidity percentage (integer)
|
|
* @param temperature temperature in Celsius (integer)
|
|
* @retval None
|
|
*/
|
|
static void print_reading(uint8_t humidity, uint8_t temperature)
|
|
{
|
|
char buf[4];
|
|
uart_puts("Humidity: ");
|
|
uint_to_str(humidity, buf);
|
|
uart_puts(buf);
|
|
uart_puts("% Temperature: ");
|
|
uint_to_str(temperature, buf);
|
|
uart_puts(buf);
|
|
uart_puts(" C\r\n");
|
|
}
|
|
|
|
/**
|
|
* @brief Print a read failure message over UART.
|
|
* @retval None
|
|
*/
|
|
static void print_failure(void)
|
|
{
|
|
uart_puts("DHT11 read failed - check wiring on GPIO4\r\n");
|
|
}
|
|
|
|
/**
|
|
* @brief Initialize clocks, timer, DHT11, and announce over UART.
|
|
* @retval None
|
|
*/
|
|
static void dht11_setup(void)
|
|
{
|
|
uint8_t dummy_h;
|
|
uint8_t dummy_t;
|
|
xosc_set_clk_ref();
|
|
dht11_timer_release_reset();
|
|
dht11_timer_start_tick();
|
|
dht11_init();
|
|
delay_ms(DHT11_POLL_MS);
|
|
dht11_read(&dummy_h, &dummy_t);
|
|
delay_ms(DHT11_POLL_MS);
|
|
uart_puts("DHT11 driver initialized on GPIO4\r\n");
|
|
}
|
|
|
|
/**
|
|
* @brief Read the sensor once and print results or failure.
|
|
* @retval None
|
|
*/
|
|
static void poll_sensor(void)
|
|
{
|
|
uint8_t humidity;
|
|
uint8_t temperature;
|
|
if (dht11_read(&humidity, &temperature))
|
|
print_reading(humidity, temperature);
|
|
else
|
|
print_failure();
|
|
delay_ms(DHT11_POLL_MS);
|
|
}
|
|
|
|
int main(void)
|
|
{
|
|
dht11_setup();
|
|
while (1)
|
|
poll_sensor();
|
|
}
|