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I am trying to configure a splashscreen in u-boot on an orange pi zero plus using Armbian.
The screen is connected through spi1 using the ST7789v chip of the LCD.
I already have used systemd to display a splashscreen however I find it slow to display something. It display something only after ~12 sec. I could probably reduce that time a bit by loading the service earlier but it would never start in 5 sec.
It seems that u-boot doesn't take in charge spi as a video output. I can see LCD, HDMI, DVI, VGA,... but no SPI. Is it possible to configure the SPI as LCD? Or to send framebuffer to the SPI to display the splashscreen?
As #KamilCuk mentioned there is no ST7789V driver in U-Boot yet. But you could write your own.
In Linux there is a frame buffer driver drivers/staging/fbtft/fb_st7789v.c which could serve as a template.
On the U-Boot side you can use drivers/video/lg4573.c as a template for a SPI framebuffer driver.
Additionally to the driver you will a device tree overlay describing the SPI device. See Documentation/devicetree/bindings/display/panel/sitronix,st7789v.yaml of the Linux kernel.
Please, send your patches upstream.
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STM32 - STM32WB55CGU6
Antenna - 2450AT18B100E
Filter - MLPF-WB-01E3
Hello everyone, please help me fix the problem with my custom PCB board and BLE.
The antenna on the board won’t work (I don't see my device via Bluetooth) in any way and I don’t know where to look, can anyone implement Bluetooth via filter MLPF-WB-01E3 and antenna 2450AT18B100E on STM32WB?
I suspect that there is a problem with the board
since I run similar code on Nucleo and I can see the device through my phone but I can't see the device through my phone
Does anyone know how to check where the error is, and check if I designed the board correctly?
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I am working on the custom build Yocto Linux running on Wayland, but I do not know how to flip the screen horizontally, as I don't see xrandr in it (I did find xorg.conf). Can someone help on this? Thanks
Wayland does not use X server see this graphic
Wayland and its clients use EGL to draw directly into the framebuffer. It can be a foundation for on overlaying X but it does not have to.
For Wayland Weston there is a solution in https://community.nxp.com/t5/i-MX-Processors/How-can-I-rotate-Wayland-weston/m-p/695720 :
I found the device name at "/var/log/weston.log". And I add these
lines to "/etc/xdg/weston/weston.ini" :
(My default screen size :1024x768 and 60Hz)
[output]
name=fbdev
mode=768x1024#60
transform=270
You can set "transform" 90 or 270 to use your display vertical.
Weston is also intended to replace X on embedded systems (https://en.wikipedia.org/wiki/Wayland_(display_server_protocol)) :
https://archive.fosdem.org/2020/schedule/event/fbdev/attachments/slides/3595/export/events/attachments/fbdev/slides/3595/fosdem_2020_nicolas_caramelli_linux_framebuffer.pdf - Back to the framebuffer !
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I have run bitbake core-image-minimal-dev properly configured for a genericx86 machine. BitBake generates a bootia32.efi, a bzImage--<stuff>.bin, an .hddimg, an .iso, a .rootfs.ext3, a .rootfs.ext4, a .rootfs.tar.bz2, and a core-image-initramfs-<stuff>.rootfs.cpio.gz. I'm interested in a method of how to dd one or more of these onto the hard disk of my target machine and boot from that hard disk.
dd if=path/to/imagefile/imagename.hddimg of=/dev/usbdevicename
You'll find the correct usb device name e.g. by plugging in the usb disk and looking at dmesg|tail output -- do not guess as mistakes will be fatal to your hard disk. A practical example from my build machine:
sudo dd if=tmp/deploy/images/intel-corei7-64/core-image-sato-intel-corei7-64.hddimg \
of=/dev/sdb \
bs=4096
Note that you probably want to use intel-corei7-64 as the machine unless you know that genericx86 is correct for your hardware: despite the name former is the common Intel BSP for anything that's not ancient (that includes big Cores, Xeons, Atoms ...).
How to boot the image depends on your target device: you may need to go to BIOS settings to select "boot from USB".
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I have two USB devices which appear as /dev/ttyACMn (a barcode reader and a motor controller). For each of them, when I try to open them in the first 15 seconds after plugging in, I get a "device or resource busy" error. After more than 15 seconds, they open fine. Do you have any idea what's causing it?
I tried using lsof to check if a process is using the device, but it finds no such process (it finds my process after I manage to connect to the device).
I'm currently using Ubuntu 14.04, kernel 3.13.0 64-bit, but I have seen this behavior in earlier Ubuntu versions too.
Thank you very much,
Noam
I think the problem is ModemManager. It scans serial interfaces on startup to see, if they belong to a modem.
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I am learning about Linux boot process on ARM processors and find that U-boot is boot from the flash and then u-boot code intialize the RAM to set up the execution environment like stack set up and all
and relocate itself.
Now my question who initialize the flash so that u-boot code can execute?
Also is it any difference booting it from NOR flash or NAND flash?
Is booting from NOR flash is faster than booting from NAND flash?
naturally someone has to program that flash the first time. And each board design determines how that actually happens, sometimes the part is programmed before being soldered down, sometimes there is a backdoor a connector you can program through, etc. Sometimes not. Sometimes the processor or other hardware on the board has some other kind of bootloader that you can use to program that normal boot flash, etc.
NOR or NAND isnt usually much of a difference, my biggest problem with the newer flashes is worrying about read-disturb. Flash reading is faster than writing and a lot of the effort is or at least needs to be in write speed and density and cost, so I would assume that is where the efforts are and not so much read speed vs write speed. If you have a read speed problem, then just copy the bootloader to ram as soon as you can and run from there, stay off the prom after that.