Skip to content

Commit

Permalink
Markdown tweaks to README
Browse files Browse the repository at this point in the history
  • Loading branch information
@caliston
caliston authored Jan 16, 2024
1 parent 49e73d8 commit 0dcbe2c
Showing 1 changed file with 105 additions and 98 deletions.
203 changes: 105 additions & 98 deletions README.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,121 +15,128 @@ sockets. You may need a riser header if the Pi's own header isn't tall enough t

2. Boot the Pi and copy the device tree overlay file by running the following:

```
git clone https://github.com/caliston/waveshare-LCD35-bookworm
cd waveshare-LCD35-bookworm
sudo cp waveshare35a-overlay.dtb /boot/overlays/waveshare35a.dtbo
```
```
git clone https://github.com/caliston/waveshare-LCD35-bookworm
cd waveshare-LCD35-bookworm
sudo cp waveshare35a-overlay.dtb /boot/overlays/waveshare35a.dtbo
```

This file tells Linux about the display hardware we've connected.
This file tells Linux about the display hardware we've connected.

3. We need to tell the Pi the existance of the .dtbo file. Edit /boot/config.txt and add to the bottom:

```
dtoverlay=waveshare35a
hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 480 320 60 6 0 0 0
hdmi_drive=2
```

While in the file, make sure the following are present and not commented out (add them if necessary):
```
dtparam=i2c_arm=on
dtparam=spi=on
disable_fw_kms_setup=1
```
and comment out the following entries:
```
#dtoverlay=vc4-kms-v3d
#max_framebuffers=2
```
Save the file. This enables SPI, sets the video mode to 480x320, and disables the native framebuffer support.
(this may cause the HDMI output to stop working.
```
dtoverlay=waveshare35a
hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt 480 320 60 6 0 0 0
hdmi_drive=2
```

While in the file, make sure the following are present and not commented out (add them if necessary):

```
dtparam=i2c_arm=on
dtparam=spi=on
disable_fw_kms_setup=1
```

and comment out the following entries:

```
#dtoverlay=vc4-kms-v3d
#max_framebuffers=2
```

Save the file. This enables SPI, sets the video mode to 480x320, and disables the native framebuffer support.
(this may cause the HDMI output to stop working.

4. Reboot the Pi:

```
sudo shutdown -r now
```

Once the Pi has come back, run `dmesg`. As it boots the display should turn grey. You should see some relevant log lines of setting up the LCD and the touch controller:

```
[ 12.075247] ads7846 spi0.1: supply vcc not found, using dummy regulator
[ 12.083302] ads7846 spi0.1: touchscreen, irq 185
[ 12.089305] input: ADS7846 Touchscreen as /devices/platform/soc/3f204000.spi/spi_master/spi0/spi0.1/input/input0
...
[ 12.420322] fb_ili9486: module is from the staging directory, the quality is unknown, you have been warned.
[ 12.421084] SPI driver fb_ili9486 has no spi_device_id for ilitek,ili9486
[ 12.438820] fb_ili9486 spi0.0: fbtft_property_value: regwidth = 16
[ 12.438866] fb_ili9486 spi0.0: fbtft_property_value: buswidth = 8
[ 12.438902] fb_ili9486 spi0.0: fbtft_property_value: debug = 0
[ 12.438928] fb_ili9486 spi0.0: fbtft_property_value: rotate = 90
[ 12.438958] fb_ili9486 spi0.0: fbtft_property_value: fps = 30
[ 12.438984] fb_ili9486 spi0.0: fbtft_property_value: txbuflen = 32768
...
[ 13.044785] graphics fb1: fb_ili9486 frame buffer, 480x320, 300 KiB video memory, 32 KiB buffer memory, fps=31, spi0.0 at 16 MHz
```

You should also see a /dev/fb0 or /dev/fb1 device appear:

```
$ ls -l /dev/fb*
crw--w---- 1 root video 29, 0 Jan 15 22:56 /dev/fb0
crw--w---- 1 root video 29, 1 Jan 16 16:54 /dev/fb1
```

You can test out this node by doing the following:
```
sudo dd if=/dev/urandom of=/dev/fb1
```

If you see multicoloured 'snow' on a part of the display you know it's working.
```
sudo shutdown -r now
```

Once the Pi has come back, run `dmesg`. As it boots the display should turn grey. You should see some relevant log lines of setting up the LCD and the touch controller:

```
[ 12.075247] ads7846 spi0.1: supply vcc not found, using dummy regulator
[ 12.083302] ads7846 spi0.1: touchscreen, irq 185
[ 12.089305] input: ADS7846 Touchscreen as /devices/platform/soc/3f204000.spi/spi_master/spi0/spi0.1/input/input0
...
[ 12.420322] fb_ili9486: module is from the staging directory, the quality is unknown, you have been warned.
[ 12.421084] SPI driver fb_ili9486 has no spi_device_id for ilitek,ili9486
[ 12.438820] fb_ili9486 spi0.0: fbtft_property_value: regwidth = 16
[ 12.438866] fb_ili9486 spi0.0: fbtft_property_value: buswidth = 8
[ 12.438902] fb_ili9486 spi0.0: fbtft_property_value: debug = 0
[ 12.438928] fb_ili9486 spi0.0: fbtft_property_value: rotate = 90
[ 12.438958] fb_ili9486 spi0.0: fbtft_property_value: fps = 30
[ 12.438984] fb_ili9486 spi0.0: fbtft_property_value: txbuflen = 32768
...
[ 13.044785] graphics fb1: fb_ili9486 frame buffer, 480x320, 300 KiB video memory, 32 KiB buffer memory, fps=31, spi0.0 at 16 MHz
```

You should also see a /dev/fb0 or /dev/fb1 device appear:

```
$ ls -l /dev/fb*
crw--w---- 1 root video 29, 0 Jan 15 22:56 /dev/fb0
crw--w---- 1 root video 29, 1 Jan 16 16:54 /dev/fb1
```

You can test out this node by doing the following:

```
sudo dd if=/dev/urandom of=/dev/fb1
```

If you see multicoloured 'snow' on a part of the display you know it's working.

5. Unfortunately the permissions on this node aren't right so we need a udev rule to fix it. Put this in /etc/udev/rules.d/99-tty.rules :
```
KERNEL=="tty[0-9]*", GROUP="tty", MODE="0660"
```

You will also need to add your user to the 'video' user if not already:
```
sudo usermod -a -G video $USER
```
```
KERNEL=="tty[0-9]*", GROUP="tty", MODE="0660"
```

You will also need to add your user to the 'video' user if not already:

```
sudo usermod -a -G video $USER
```

6. We also need to configure X11 to use this display. Put this in /etc/X11/xorg.conf.d/99-fbdev.conf :
```
Section "Device"
Identifier "Allwinner A10/A13 FBDEV"
Driver "fbdev"
Option "fbdev" "/dev/fb1"
Option "SwapbuffersWait" "true"
EndSection
```

```
Section "Device"
Identifier "Allwinner A10/A13 FBDEV"
Driver "fbdev"
Option "fbdev" "/dev/fb1"
Option "SwapbuffersWait" "true"
EndSection
```

7. Reboot the Pi. With luck you will see the windowing system (or another X11 app like Klipperscreen) appear on the display.

8. The touch input should work, but you may find its input is rotated so it's clicking on the wrong things. Edit /usr/share/X11/xorg.conf.d/40-libinput.conf and add a
CalibrationMatrix line as follows:

```
Section "InputClass"
Identifier "libinput touchscreen catchall"
MatchIsTouchscreen "on"
MatchDevicePath "/dev/input/event*"
Driver "libinput"
Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"
EndSection
```

Alternative CalibrationMatrix lines for different orientations:

- 0 degrees: `Option "CalibrationMatrix" "1 0 0 0 1 0 0 0 1"`
- 90 degrees: `Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"`
- 180 degrees: `Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"`
- 270 degrees: `Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"`
```
Section "InputClass"
Identifier "libinput touchscreen catchall"
MatchIsTouchscreen "on"
MatchDevicePath "/dev/input/event*"
Driver "libinput"
Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"
EndSection
```

Alternative CalibrationMatrix lines for different orientations:

- 0 degrees: `Option "CalibrationMatrix" "1 0 0 0 1 0 0 0 1"`
- 90 degrees: `Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"`
- 180 degrees: `Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"`
- 270 degrees: `Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"`


0 comments on commit 0dcbe2c

Please sign in to comment.