GPIO Programming

sudo apt update
sudo apt install gpiod
sudo gpiodetect

sudo apt update
sudo apt install python3-libgpiod

import gpiod
import time
import sys

# ================= Configuration =================
# Hardware: LattePanda Mu (Intel N100/N305)
# Chip: [INTC1057:00] -> gpiochip0
CHIP_NAME = 'gpiochip0'

# Pin Definition (Mapping Name to Line Offset)
PIN_GPP_F12 = 300

# Select the target pin for this demo
TARGET_LINE_OFFSET = PIN_GPP_F12
# ===============================================

def main():
    chip = None
    line = None

    try:
        # 1. Initialize Chip
        chip = gpiod.Chip(CHIP_NAME)

        # 2. Get the specific line (GPP_F12)
        line = chip.get_line(TARGET_LINE_OFFSET)

        # 3. Request Control
        # Set direction to OUTPUT
        line.request(consumer="GPIO_Toggle_Demo", type=gpiod.LINE_REQ_DIR_OUT)

        print(f"Demo Started: Blinking Pin GPP_F12 (Line {TARGET_LINE_OFFSET})...")
        print("Press Ctrl+C to stop.")

        # 4. Main Loop
        while True:
            # Set High Level
            line.set_value(1)
            print(f"[{time.strftime('%H:%M:%S')}] GPIO -> HIGH (1)")
            time.sleep(1)

            # Set Low Level
            line.set_value(0)
            print(f"[{time.strftime('%H:%M:%S')}] GPIO -> LOW  (0)")
            time.sleep(1)

    except KeyboardInterrupt:
        print("\nDemo stopped by user (Ctrl+C).")

    except Exception as e:
        print(f"An error occurred: {e}")

    finally:
        # 5. Clean up resources
        # The 'finally' block GUARANTEES this runs even after Ctrl+C
        if line:
            line.release()
            print("GPIO Line released.")
        if chip:
            chip.close()
            print("GPIO Chip closed.")

if __name__ == "__main__":
    main()

sudo python3 gpio_toggle_demo.py

import gpiod
import time

# ================= Configuration =================
# Hardware: LattePanda Mu
# Chip: gpiochip0
# Pin: GPP_F12 -> Line Offset 300
CHIP_NAME = 'gpiochip0'
PIN_GPP_F12 = 300
# ===============================================

def main():
    chip = None
    line = None

    try:
        # 1. Initialize Chip
        chip = gpiod.Chip(CHIP_NAME)

        # 2. Get the line
        line = chip.get_line(PIN_GPP_F12)

        # 3. Request Control as INPUT
        # We specify LINE_REQ_DIR_IN for input mode
        line.request(consumer="GPIO_Input_Demo", type=gpiod.LINE_REQ_DIR_IN)

        print(f"Demo Started: Reading Input from GPP_F12 (Line {PIN_GPP_F12})...")
        print("Connect this pin to GND or VCC (3.3V) to see changes.")
        print("Press Ctrl+C to stop.")

        # 4. Main Loop
        while True:
            # Read current value (0 or 1)
            value = line.get_value()

            print(f"[{time.strftime('%H:%M:%S')}] Input Value: {value}")

            # Wait 1 second
            time.sleep(1)

    except KeyboardInterrupt:
        print("\nDemo stopped by user.")
    except Exception as e:
        print(f"Error: {e}")
    finally:
        # 5. Cleanup
        if line:
            line.release()
        if chip:
            chip.close()
        print("Resources released.")

if __name__ == "__main__":
    main()

sudo apt update
sudo apt install libgpiod-dev

#include <gpiod.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <stdbool.h>

// ================= Configuration =================
// Hardware: LattePanda Mu (Intel N100/N305)
// Chip: gpiochip0
// Pin: GPP_F12 -> Line Offset 300
// ===============================================

#define CHIP_NAME "gpiochip0"
#define PIN_GPP_F12 300

// Flag for the main loop, modified by signal handler
static volatile sig_atomic_t keep_running = 1;

// Signal Handler for Ctrl+C
void signal_handler(int sig) {
    keep_running = 0;
}

int main(void) {
    struct gpiod_chip *chip;
    struct gpiod_line *line;
    int ret;

    // 1. Register signal handler (Ctrl+C)
    signal(SIGINT, signal_handler);

    // 2. Open the GPIO Chip
    chip = gpiod_chip_open_by_name(CHIP_NAME);
    if (!chip) {
        perror("Open chip failed");
        return 1;
    }

    // 3. Get the specific line
    line = gpiod_chip_get_line(chip, PIN_GPP_F12);
    if (!line) {
        perror("Get line failed");
        gpiod_chip_close(chip);
        return 1;
    }

    // 4. Request the line as OUTPUT
    // "LattePanda_C_Demo" is the consumer label visible in gpioinfo
    ret = gpiod_line_request_output(line, "GPIO_Toggle_Demo", 0);
    if (ret < 0) {
        perror("Request line as output failed");
        gpiod_chip_close(chip);
        return 1;
    }

    printf("Demo Started: Blinking Pin GPP_F12 (Line %d)...\n", PIN_GPP_F12);
    printf("Press Ctrl+C to stop.\n");

    // 5. Main Loop
    while (keep_running) {
        // Set High
        gpiod_line_set_value(line, 1);
        printf("GPIO -> HIGH (1)\n");
        sleep(1);

        if (!keep_running) break;

        // Set Low
        gpiod_line_set_value(line, 0);
        printf("GPIO -> LOW  (0)\n");
        sleep(1);
    }

    // 6. Cleanup Resources
    printf("\nReleasing resources...\n");
    gpiod_line_release(line);
    gpiod_chip_close(chip);
    printf("Done.\n");

    return 0;
}

gcc -o gpio_toggle_demo gpio_toggle_demo.c -lgpiod
sudo ./gpio_toggle_demo

#include <gpiod.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>

// ================= Configuration =================
#define CHIP_NAME "gpiochip0"
#define PIN_GPP_F12 300
// ===============================================

static volatile sig_atomic_t keep_running = 1;

// Signal Handler for graceful exit
void signal_handler(int sig) {
    keep_running = 0;
}

int main(void) {
    struct gpiod_chip *chip;
    struct gpiod_line *line;
    int value;
    int ret;

    signal(SIGINT, signal_handler);

    // 1. Open Chip
    chip = gpiod_chip_open_by_name(CHIP_NAME);
    if (!chip) {
        perror("Open chip failed");
        return 1;
    }

    // 2. Get Line
    line = gpiod_chip_get_line(chip, PIN_GPP_F12);
    if (!line) {
        perror("Get line failed");
        gpiod_chip_close(chip);
        return 1;
    }

    // 3. Request as INPUT
    ret = gpiod_line_request_input(line, "GPIO_Input_Demo");
    if (ret < 0) {
        perror("Request input failed");
        gpiod_chip_close(chip);
        return 1;
    }

    printf("Demo Started: Reading Input from GPP_F12 (Line %d)...\n", PIN_GPP_F12);
    printf("Press Ctrl+C to stop.\n");

    // 4. Main Loop
    while (keep_running) {
        // Read Value
        value = gpiod_line_get_value(line);

        if (value < 0) {
            perror("Read value failed");
        } else {
            printf("Input Value: %d\n", value);
        }

        sleep(1);
    }

    // 5. Cleanup
    printf("\nReleasing resources...\n");
    gpiod_line_release(line);
    gpiod_chip_close(chip);

    return 0;
}

GPIO Number = Base Address + Offset Address

sudo -i

cd /sys/class/gpio
echo 812 > export
cd gpio812
echo out > direction
# Set output to High (Logic 1)
echo 1 > value
# Set output to Low (Logic 0)
echo 0 > value

# Ensure you are inside the gpio812 directory
echo in > direction
# Read current value(0 or 1) every 1 second
watch -n 1 cat value

cd /sys/class/gpio
echo 812 > unexport