The framebuffer wants an image in the 16 bit RGB565 format. This means 16 bit depth and more precisely 5 bits for Red, 6 for Green, and 5 for Blue. The framebuffer just wants raw data so we have to strip metadata and headers.
convert /path/to/image.jpg\["$fbw"x"$fbh"^\] +flip -strip -define bmp:subtype=RGB565 bmp2:- | tail -c $(( fbw * ...
Ok, I figured out the approach! Turns out there is a catch with just 2 files that makes it cache regardless.
I created 2 symlinks to the original image file, and specified -cachemem 0. This triggered it to re-read the file on every refresh. So this allows me to update the image every 60 seconds:
fbi -T 1 -d /dev/fb0 -a -noverbose -t 60 -cachemem 0 /tmp/...
In thanks to Gerard's answer I was able to find a comment in that bug chain with a successful workaround to this problem, it took me some time to find so I will provide it here for anyone else searching:
echo blacklist vc4 > /etc/modprobe.d/blacklist-vc4.conf
To explain, Sylvain Pasche avoids this hangup by blacklisting the vc4 driver. Ryniker notes ...
A device tree overlay which allows the use of an ssd1306 via i2c was merged into the Raspberry Pi OS (Raspbian) kernel in early 2019 (https://github.com/raspberrypi/firmware/issues/1098).
To use this, you could add dtoverlay=ssd1306 to /boot/config.txt.
If you want to use the ssd1306 as your primary console, then you can prevent the Pi GPU being used as the ...
Are you exactly running con2fbmap 1 1 after the display drivers are loaded?
If the desktop runs on HDMI also with the Framebuffer set to fb1, then there is an option in /usr/share/X11/xorg.conf.d/99-fbturbo.conf.
Look for the line Option "fbdev" "/dev/fb0" and remove/comment it.
It is this issue: https://github.com/notro/fbtft/issues/63
Did you consider 2D Game engines/libraries ? Because OpenGL/OpenVG are very low-level and don't do font handling , the added "belt and suspenders" of those libs will make your life much easier :
I understand ImageMagic's convert doesn't support RGB565, which is the typical 16-bit framebuffer format. It's possible to perform the conversion with scripts, as the linked thread suggests, but those are not exactly one-liners.
I would rather try to switch to 32-bit framebuffer on your Pi 4, similar to what you had on Pi 3:
fbset -fb /dev/fb0 -depth 32
The SPI driver (spi-bcm2708_dma.c) appears to be written for the earlier model Pis. The Pi2 model uses a different base address for the peripherals.
I didn't look at how the driver is using DMA but there have also been changes in this area. I'm not sure if the DMA changes affect kernel modules.
I haven't looked through the rest of the code.
You'll at ...
I was struggling with this as well since the 7" screen is a bit too small for my old eyes to do actual development.
The solution is to add a line to /boot/config.txt as described in https://www.raspberrypi.org/blog/the-eagerly-awaited-raspberry-pi-display/ :
"The Raspberry Pi will now automatically detect the display and use it as the default display (...
xinit(1) is the script/command you are looking for!
Literal excerpt from the manpage:
EXAMPLESBelow are several examples of how command line arguments in xinit are used.
xinit This will start up a server named X and run the user's .xinitrc, if it exists, or else start an xterm.xinit -- /usr/bin/Xvnc :1 This is how one could start a specific type of ...
I found a well structured program in git hub :
which handles my task. to open a .png file and show it on the HDMI display while DSI screen is functioning as the main screen on the raspberry pi.
after download and running the 'make' in the subfolder of the program, an executable file will be generated in ...
Framebuffer color depth can be changed by fbset
fbset -fb /dev/fb0 -depth 16 ...
Writing the desired framebuffer configuration in /etc/fb.modes could help making the change permanent, but I never tried that personally.
The Pi has 3 "components" the CPU, GPIO and Video Core which are relatively independent.
As you might guess the Video Core is responsible for display, and will continue to display the contents of the frame buffer, even if the CPU is not running.
In early versions of Raspbian, you could halt the CPU (and later restart) and the display and programs would ...
Allocate two framebuffers from config.txt
Tell Xorg to use only one screen: create xorg.conf with sudo xorg -configure and edit it to keep only the first device. If Xorg is not using the second screen anyway, skip this step.
Run omxplayer on the second screen with --display 7 as described here.
T1 can be estimated reasonably well by toggling a GPIO pin.
T2 can be measured with an HDMI analyzer or a high-end oscilloscope. Don't expect this to be cheap.
I bet Broadcom have already measured the delay themselves but unfortunately I have no idea what it takes to get such information from them. Some companies (like TI) are quite cool and send you a lot ...
Link with instructions to build SDL2 (no X) on Pi:
you will get hardware accelerated graphics with SDL2
For more fun just use dispmanx/EGL/OpenVG for hardware accelerated graphics.
A user here has reported that "The sdl2-config --cflags --libs compiler option found on ...
You can try to use Debian Stretch with Raspberry Pi Desktop for PC and Mac. I don't know if it fit your needs, in particular accessing the hardware and framebuffer but I think it is worth to have a look at it.
Looks like the unsigned char pointer was actually casting to unsigned char and thus truncating the data to only 8 bits, 5 of which were blue, and 3 were least significant bits of green.
Fixed by changing
unsigned char *fbp_2 = NULL;
uint16_t *fbp_2 = NULL;
color_out = ((red_in >> 3) << 10) | ((green_in >> 3) << 5) | ((...
Have another program which runs on the user's account and is autostarted whenever the user logs in. That program waits for notifications from your background daemon received via a unix domain socket or TCP socket, then opens a fullscreen window with the appropriate message.
That's pretty much how every other notification service is implemented.
This Config need to be use with ssh remote
Please Pay attentions xD
First of all install normal libray LCD-SHOW-XX-XX-XX.TAR.GZ
extract and find lcd35-show
and then run => ./lcd35-show
Install kedei library with LCD35 and then chose LCD-hdmi in kedei
go to website http://kedei.net/raspberry/raspberry.html
download LCD_show_v6_x_X into your ...
unfortunatey the re-install you mentioned does not work since the kernel version seems not to be in the repository any more.
Since I noticed the issue afterwards the upgrade, I was in the same situation as Innidael.
Nevertheless I found the necessary packages still being stored in the apt cache /var/cache/apt/archives/. Therefore I was able to install both ...
Same for me (I'm using the same display).
Solved it by re-installing and setting the packages raspberrypi-kernel and raspberrypi-bootloader to "hold":
sudo apt-mark hold raspberrypi-kernel raspberrypi-bootloader
It might also work to "revert" to the old kernel/bootloader (instead of reinstalling) by doing:
sudo apt-get install ...
I got 2D vector graphics library working, using it from C Language, currently with a 128x128 OLED display on a headless Raspberry Pi 3B, using the following recipe. Note: X-Windows (X11) is not installed (e.g. Raspian lite edition). As for performance considerations, OpenVG's claim to fame is that it utilizes available HW acceleration layer(s) rather than ...
We cannot run two separate X because we simply don't have second frame buffer and need some development to get another frame buffer working. However, we are still capable to run both the touch and HDMI screen if the application is modified to do so. OMX player as example.
omxplayer --display 5 xxx.avi this will play the video on the HDMI screen while the X ...
framebuffer_width/height only set's the resolution of the text console.
hdmi_mode 13 is 720x240, what you are seeing is correct, I had the same initial dramas however found some information on how to set 320x240 using a custom mode:
Add the below to your config.txt file:
# uncomment if hdmi display is not detected and composite is being output
Do you know another way to test the framebuffer?
the command "dmesg" gives out all loaded modules, if you loaded a module correctly then it should appear at the end of a gigantic output of modules.
[roughly the last 10 lines are description of the module]
fbi -d /dev/fb1 -a happycat_oled_64.ppm
using "DejaVu Sans Mono-16", pixelsize=16,...