🛠 Faire clignoter une LED via le GPIO avec libgpiod

Objectives

Discover the 40-pin connector on the Orange Pi 3B (Rockchip RK3566) and blink an LED using libgpiod, the modern Linux API based on character devices — without using the legacy gpio export sysfs mechanism.

Hardware

• Orange Pi 3B running Armbian (Debian/Ubuntu), powered via USB-C at 5 V / 3 A
• 1 LED + 330 Ω resistor, female-to-male Dupont cables
• Display or SSH session

Full Code

sudo apt install gpiod
gpiodetect                 # gpiochip0 = gpio0 ... gpiochip4 = gpio4 (RK3566)
gpioinfo gpiochip1
# Banques Rockchip exposées par libgpiod : PA=0-31, PB=32-63, PC=64-95, PD=96-127
# Exemple : gpio1_b3 = 32+3 = 35 sur gpiochip1 (vérifier une broche libre sur le plan officiel 40 broches)
sudo gpioset -c gpio1 --time=1 35=1        # niveau haut pendant 1 s
# Clignotage 10 fois
for i in $(seq 1 10); do sudo gpioset -c gpio1 --time=0.2 35=1; sleep 0.3; done
# Récupérer la LED heartbeat système (gpio0_C0 = ligne 64) si elle gêne :
echo none | sudo tee /sys/class/leds/green\:heartbeat/trigger

Expected Verification

gpiodetect displays gpiochip0 through gpiochip4. The LED lights up for approximately 1 second with gpioset --time=1, then blinks 10 times in the loop. The board's green heartbeat LED (gpio0_C0, defined in the mainline device tree) blinks under Linux; this is normal.

Common Errors

• Using old GPIO sysfs numbers inherited from Raspberry Pi tutorials: under Armbian/Rockchip, the pins are the gpio0…gpio4 banks exposed by libgpiod, not BCM numbers.
• Selecting the wrong gpiochip: gpio1_b3 is line 35 of gpiochip1, not gpiochip0.
• Reversing the LED (anode/cathode) or forgetting the 330 Ω resistor.
• Powering the board too weakly: >