kedei 3.5 inch tft lcd display spi with touch screen made in china
While googling for any info about lcd controller I came across this page: http://heikki.virekunnas.fi/2015/raspberry-pi-tft/, author managed to get from manufacturer patch file for kernel sources and tested it with 4.1.y - on which lcd worked. But still LCD replace HDMI, but I want to use this screen as additional for user interaction, while the bigger on HDMI as presentation monitor.
Since, fbtft has been merged with rpi kernel, so the fb drivers (including ili9341.c) was moved to fbtft_device driver (so the author of page can"t compile latest kernel with driver+patch).
So something about hardware, which I reverse engineered by the "hard way" - "grab multimeter and run through all LCD FPC pins and shift register pins"
Now I noticed there is "9486L" which can suggest that LCD screen is controlled by ILI9486L, I found this LCD on taobao too but I can"t contact seller.
I"m pretty sure about D/C (Pin 37 on LCD) and Reset (Pin 19 on LCD) pins by looking into driver code, but I can"t identify other signals (WR/RD/CS/etc...)
[ 4.838806] input: MOSART Semi. Rapoo 2.4G Wireless Touch Desktop as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/1-1.3:1.0/0003:24AE:1000.0001/input/input1
[ 4.862704] hid-generic 0003:24AE:1000.0001: input,hidraw0: USB HID v1.10 Keyboard [MOSART Semi. Rapoo 2.4G Wireless Touch Desktop ] on usb-bcm2708_usb-1.3/input0
[ 4.902783] input: MOSART Semi. Rapoo 2.4G Wireless Touch Desktop as /devices/platform/bcm2708_usb/usb1/1-1/1-1.3/1-1.3:1.1/0003:24AE:1000.0002/input/input2
[ 4.926400] hid-generic 0003:24AE:1000.0002: input,hiddev0,hidraw1: USB HID v1.10 Mouse [MOSART Semi. Rapoo 2.4G Wireless Touch Desktop ] on usb-bcm2708_usb-1.3/input1
- Controller is not ILI9341/ILI9325 - those are for smaller displays (320x240, etc...), I guess this might be ILI9486/9488 because they are for 480x320 displays. But when I compared init with DS it does not fit right so LCD can have a clone of ILI9486/9488 ...
- Module use only SPI interface and two CE signals (CE0 for touch controller, CE1 for LCD shift registers - compared to others lcd modules, in KeDei module this is swapped),
When surfing for information on 3.5 ” TFT touchscreens for the Raspberry Pi,to improve the TinyLCD experience, I stumbled upon AliExpress where several shops offer a 3.5″ LCD TFT Touch Screen Display for incredible low prices.
Here my experiences with the screen: quite slow refresh, not too high contrast, crisp screen, touch works, software works but is already outdated, but considering the price this screen is well worth the money! If I compare it to the NeoSec screen it is a better deal for applications with a high contrast theme and no demand on smooth video.
So now for the test. On the sellers page an URL is placed to get the software, on a Google drive. Not a clickable url, but an image with a long filename to type over …. Oh well, I got the archive.
Update June 2016: There is now a download/information page at http://osoyoo.com/driver/rpiscreen.php. Images for more versions (mine i 2.0, latest is 6.2) are available there. Alternative ishttp://kedei.net/raspberry/raspberry.html with Kali Ubuntu drivers too for version 3.0 and up.
The archive contains an image of Raspbian with the LCD driver installed. The image is quite current, and fit for B, B+ or 2 B. When I bought the screen an older image, build in augustus 2015, was downloadable, the kernel is quite fresh built, early October 2015.
The image supplied is wheezy, 3.18.9-v7 #27 SMP PREEMPT Sun Oct 4 23:57:41 CST 2015 armv7l. So quite a recent system! Also the Model 1 B and B+ kernel is present, also just current wheezy.
Now the bad news: no word how these kernels were build. So we are stuck with wheezy for now until the Chinese supply a more current build, hopefully based upon jessie. Until then: be careful updating the system by holding back on kernel updates.
The system uses SPI to copy the screen contents to the LCD screen, and some GPIO’s for the touchscreen. Other GPIOs are free, and the connector construction leaves these pins indeed accessible!
I orderer a 3.5″ SPI touchscreen with a Raspberry Pi 2 and a case, thinking it would be easy to set up, as it seemed to be like the one here. Unfortunately that was not the case.
With some googling I found out it was made by KeDei LCD and exactly this screen. Identifying strings on the screens were “Madei in KeDei of china”, “3.5 linch SPI TFTLCD”, “480*320 16bit/18bit” and “vision 1.0 2015/6/11”. I hope the guys who made this screen can write code better than english… Seems like it requires custom drivers by KeDei. Drivers could be downloaded from Baidu and they include the diff to compile your custom kernel. I haven’t compiled kernels before, so lets see if I could manage without doing that.
I downloaded drivers and installed them in a fresh installation of Raspbian. They worked, somewhat at least. I could see console in the screen and also LXDE started in it. However it seemed to override HDMI output completely, as it was /dev/fb0 and no other framebuffers were present. Touchscreen appeared in /dev/input/event0, but I couldn’t get it respond. Probably the touch sensor is defective, as the glass on the screen also had a crack. I did get a free resend however, so I’ll see whether it was defective hardware.
The drivers replaced current kernel with a custom 3.18.x version with drivers in it, so you can’t update kernel if using that method. Perhaps I should try to compile more recent kernel with drivers.
I installed Ubuntu on my Macbook Pro on an external hard drive (which is a whole another story, thanks to EFI), so I could follow instructions on Raspberry Pi pages. Compiling on RPi is quite slow (tried that overnight), so cross compiling is the way to go. Following the instructions worked pretty well, however I cloned tools to my home directory and added /home/heikki/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin to my path. After that everything worked as expected. After cloning and changing branch to rpi-4.1.y I patched semi-manually from the supplied diff from KeDei, however I have uploaded my updated diff to make it easier for you. There’s instructions on patching too, but long story short it’s “cat
Update: I accidentally updated kernel with apt-get, so I tried to compile the kernel to the latest. However I noticed the patch missed a whole file, which belongs to drivers/video/fbdev/ and is attached here: ili9341.c.I still couldn’t get it right, so I just installed the previously compiled kernel.
You should now have two framebuffer devices, /dev/fb0 and /dev/fb1. I’m not quite sure how the fbtft library interferes with the patch, as it seems to be activated too, but it works so no problem. (Actually I first activated module fb_ili9341, so you can try that too, if it contributed to my success). You can change to console to fb1 by command “con2fbmap 1 1” and back with “con2fbmap 1 0“, or on boot by editing /boot/cmdline.txt: add “fbcon=map:1” to the line somewhere. You can also change the font with “fbcon=font:ProFont6x11“. More things like this here.
The framerate on this screen is really slow, something like 0.5 secs to refresh the screen, so no video playback on this screen. For simple GUIs probably quite sufficient. Haven’t tried whether backlight can be controlled, probably not, so always on.
I’ll test the touchscreen with custom kernel later when I get the new unit. The touchscreen driver seems to be added (/dev/input/event2 for me with Logitech keyboard/mouse connected), so it might work.
The RPi LCD can be driven in two ways: Method 1. install driver to your Raspbian OS. Method 2. use the Ready-to-use image file of which LCD driver was pre-installed.
3) Connect the TF card to the Raspberry Pi, start the Raspberry Pi. The LCD will display after booting up, and then log in to the Raspberry Pi terminal,(You may need to connect a keyboard and HDMI LCD to Pi for driver installing, or log in remotely with SSH)
1. Executing apt-get upgrade will cause the LCD to fail to work properly. In this case, you need to edit the config.txt file in the SD card and delete this sentence: dtoverlay=ads7846.
This LCD can be calibrated through the xinput-calibrator program. Note: The Raspberry Pi must be connected to the network, or else the program won"t be successfully installed.
I finally received my 3.5" KeDei 480x320 16bit/18bit version 3.0 TFT LCD touchscreen from Hong Kong. It only connects through the GPIO pins. I plugged it into my Raspberry Pi 2 and I was met with a white screen when I tried both the Ubuntu and Raspbian images.
I have updated Raspbian, I know that my good power supply is good, and I tried enabling the SPI kernel module through the Raspberry Pi Configuration GUI since the touchscreen says that it connects via SPI. The only thing that I think could be wrong now is that the drivers are not installed or that I don"t have the right kernel.
If I can get the touchscreen to function on either the Ubuntu or the Raspbian image, then I will just take the one that works. Though if both could work flawlessly I think I would prefer using the Ubuntu image since I am more familiar with it.
I had in plans to create a custom driver but I decided this is not worth my time. I"m going to "re-interface" this lcd to be supported by fbtft. I have a prototype pcb with fbtft-spi interface ready (I have to send this project to pcb prototype service).
Unfortunatly, because of my "spider-circuit" I"ve broken my lcd (I"ve made a some short
Ms.Josey 
Ms.Josey