Architectures/ARM/Raspberry Pi/HATs

Raspberry Pi HATs

This page will be used to document using various HATs on the Raspberry Pi. Please feel free to add notes pertaining to other HATs or additions to the existing entries.

For all HATs

Remove the symlink for the dtb:

rm /boot/dtb

Prevent the symlink from being recreated on kernel upgrade.

echo "FirmwareDT=True" >> /etc/u-boot.conf

You now need to add the overlay for the HAT to the '/boot/efi/config.txt'. Below are some examples.

Sense Hat

Edit the '/boot/efi/config.txt' to add the overlay

dtoverlay=rpi-sense

Working

• Humidity Sensor (hts221)
• Barometer (lps25h)
• Magnetometer (lsm9ds1_magn)
• Temperature (hts221, lps25h)

Not Working

• 8x8 LED matrix display
• Small 5 button joystick

Adafruit PiTFT Plus (3.5 inch Resistive Touch screen)

To use the screen you will need to install 'bcm283x-firmware-20191118-1.68ec481.fc31' or later. To use the touch features of the screen you also need to install 'kernel-5.4.0-0.rc8.git0.1.fc32' or later.

Edit the '/boot/efi/config.txt' to add the overlay

dtparam=i2c_arm=on
dtoverlay=pitft35-resistive
hdmi_force_hotplug=1

Add to the kernel parameters

fbcon=map:10 fbcon=font:ProFont6x11

Due to a bug the kernel module will not load automatically. On boot the module can be loaded with:

modprobe hx8357d

Due to a bug with the VC4 driver you will also need to blacklist it:

echo "blacklist vc4" >> /etc/modprobe.d/blacklist-vc4.conf

To workaround the bug and have it load automatically use:

echo hx8357d >> /etc/modules-load.d/hx8357d.conf