A Raspberry Pi Hat for testing embedded Linux boards.
Key features:
- Well visible 23mm LEDs, red & green
- Buzzer
- One-Wire interface
- 3.3V UART interface (same pin-out as the FTDI UART cable)
- 2 Grove connectors with 2 digital outputs each
- EEPROM to store the hat-id
You may find this HAT useful in embedded Linux flash- or test stations. Connect up to 4 relays to control the board power and boot pins.
Compile the device tree overlay
dtc -@ -I dts -O dtb -o test_pi_overlay.dtbo test_pi_overlay.dts
Install the device tree overlay
sudo mv test_pi_overlay.dtbo /boot/overlays/
Edit /boot/config.txt to load the overlay at boot:
dtoverlay=test_pi_overlay
Reboot the Raspberry Pi:
sudo reboot
Check One-Wire:
ls /sys/bus/w1/devices/
If you have a 1-Wire device (e.g., DS18B20 sensor), it should appear here.
Check UART:
ls -l /dev/serial*
It should show /dev/serial0 mapped to ttyS0.
Toggle Buzzer Output:
# Buzzer ON
sudo gpioset -c gpiochip0 6=1
# Buzzer OFF
sudo gpioset -c gpiochip0 6=0
Toogle LED Outputs:
# Green LED ON/OFF
sudo gpioset -c gpiochip0 12=1
sudo gpioset -c gpiochip0 12=0
# Red LED ON/OFF
sudo gpioset -c gpiochip0 13=1
sudo gpioset -c gpiochip0 13=0
Toggle Digital Outputs:
# Grove 1 DO0 ON/OFF
sudo gpioset -c gpiochip0 21=1 -z
sudo gpioset -c gpiochip0 21=0 -z