LCD display HAT for Raspberry Pi

lcd_hat_rpi.md

For the LCD/Joystick HAT: https://www.waveshare.com/1.44inch-lcd-hat.htm

PIN Mapping:

Symbol	Raspberry Pi PIN (BCM)	Description
KEY1	P21	Button 1/GPIO
KEY2	P20	Button 2/GPIO
KEY3	P16	Button 3/GPIO
Joystick Up	P6	Joystick Up
Joystick Down	P19	Joystick Down
Joystick Left	P5	Joystick Left
Joystick Right	P26	Joystick Right
Joystick Press	P13	Joystick Press
SCLK	P11/SCLK	SPI clock input
MOSI	P10/MOSI	SPI data input
DC	P25	Data/Command selection (high for data, low for command)
CS	P8/CE0	Chip selection, low active
RST	P27	Reset, low active
BL	P24	Backlight

LCD Display

Configuration

1. Ensure that packages are installed:

apt-get install fbset raspi-config raspi-gpio

2. Enable SPI:

raspi-config  # Select interface / SPI / Enable

3. Load the following modules at boot-time, by adding these lines in /etc/modules

spi-bcm2835
fbtft_device

4. Provide configuration for the fbtft device, by creating the file /etc/modprobe.d/fbtft.conf:

options fbtft_device name=adafruit18_green gpios=reset:27,dc:25,cs:8,led:24 speed=40000000 bgr=1 fps=60 custom=1 height=128 width=128 rotate=180

5. Reboot

6. You should get a new device called fb1

ls /dev/fb*

Using it

echo 0 > /sys/class/backlight/fb_st7735r/bl_power  # On
echo 1 > /sys/class/backlight/fb_st7735r/bl_power  # Off

fbset -i -fb /dev/fb1

mode "128x128"
    geometry 128 128 128 128 16
    timings 0 0 0 0 0 0 0
    nonstd 1
    rgba 5/11,6/5,5/0,0/0
endmode

Frame buffer device information:
    Name        : fb_st7735r
    Address     : 0
    Size        : 32768
    Type        : PACKED PIXELS
    Visual      : TRUECOLOR
    XPanStep    : 0
    YPanStep    : 0
    YWrapStep   : 0
    LineLength  : 256
    Accelerator : No

ffmpeg -v 0 -y       \
    -i imagefile.png \
    -vf scale=128:128 -vcodec rawvideo -f rawvideo -pix_fmt rgb565 - > /dev/fb1

Keys / Joystick

With gpio-keys

In file /boot/config.txt

# KEY 1/2/3
dtoverlay=gpio-key,gpio=21,gpio_pull=up,active_low=1,label=key1,keycode=1
dtoverlay=gpio-key,gpio=20,gpio_pull=up,active_low=1,label=key2,keycode=2
dtoverlay=gpio-key,gpio=16,gpio_pull=up,active_low=1,label=key3,keycode=3

# Joystick
dtoverlay=gpio-key,gpio=6,gpio_pull=up,active_low=1,label=up,keycode=103
dtoverlay=gpio-key,gpio=19,gpio_pull=up,active_low=1,label=down,keycode=108
dtoverlay=gpio-key,gpio=5,gpio_pull=up,active_low=1,label=left,keycode=105
dtoverlay=gpio-key,gpio=26,gpio_pull=up,active_low=1,label=right,keycode=106
dtoverlay=gpio-key,gpio=13,gpio_pull=up,active_low=1,label=enter,keycode=28

With sysfs

for pin in 21 20 16 6 19 5 26 13 ; do
  raspi-gpio set $pin pu
  echo $pin > /sys/class/gpio/export
done

cat /sys/class/gpio/gpio$pin/value

thx, good work.

Visible screen is only 128 x 127 pixels.

Mine is still full white .. and no fb1 detected.. using a RASPBERRY PI OS LITE only cmd no ddesktop ... any idea??

Mine is still full white .. and no fb1 detected.. using a RASPBERRY PI OS LITE only cmd no ddesktop ... any idea??

For a little while now, the Raspberry Pi OS kernel hasn't included the fbtft_device module, so unless you use an older kernel this guide won't work.