kedei 3.5 inch spi tft lcd arduino quotation

Is there a chance of getting it working with an Arduino Uno R3 or Mega2560? The graphics libraries that use SPI that I"ve found keep mentioning the RST and DC lines, which aren"t present on this board.

I haven"t had the opportunity to try it on a Raspberry Pi yet. From pinouts of raspi (googled images) they only have one long strip of GPIO/etc connectors, do they not? Even if plugging this board onto the 40-pin connector, where the two 5V pins match up, on the raspi the opposing two aren"t GND, they"re listed as "+3,3V" and "SDA". Something tells me that.. well, either I"m missing something, or this display needs some form of connector between itself and the raspi it"s meant to run off originally. (Oddly enough, they came with raspi-with-TFT-on-top plastic enclosures, which wouldn"t leave any space for rewiring pins.)

I doubt it. It would be a lot cleaner with regular SPI for both. You just change mode each time. e.g. 9-bit mode #3 for TFT. 8-bit mode #0 for the XPT.

Ah-ha. The HC595 is a shift register. They might use them to produce 16-bit parallel to drive the TFT. If they do, it will be a nightmare. Even worse than 9-bit SPI.

Well, it"ll be interesting to see if I get this to work eventually. A quick guess would be that with L_CS pulled low, the LCD chip gets to talk with the MISO/MOSI lines. After initializing it, I suppose the next step will be to (read datasheet..) and see if the MISO/MOSI-lines are used to clock out display data with L_CS high so the LCD chip doesn"t listen to that garbage, or if it is meant to be fed through the LCD chip aswell.

16-bit modules are cheaper than SPI display modules. So it is quite possible that he has crippled the display with shift registers instead of buying a proper SPI module.

Oh, this makes it easier - googling for the tarball I needed (lcd_show_v6 for my board since it"s got "v6.1" printed on it) got me to OsoYooTFT/README.md at master · jgamblin/OsoYooTFT · GitHub and http://en.kedei.net/raspberry/raspberry.html

Hrmm.. I don"t think source is included. In the lcd_show_xx blobs are just kernels and modules, with a couple of very small scripts to copy the LED or HDMI kernel to the /boot place of the filesystem. (And no error checking, if you try copying the LED kernel, it backups the original kernel, but if you then run the copy-LED-kernel command again, it happily overwrites your original kernel, leaving you with two LED-enabled kernels and no original. hrrf..)

Well, I downloaded the whole 35MB .GZ file. Unpacked it and found 3402 .ko files. I presume that these are kernel object files. Nothing that looked remotely like source files for your TFT display.

Since the ILI9481 can be driven directly by SPI, this seems a crazy way to do things. Especially since a HC595 might be clockable at 100MHz but you need to wiggle all 24-bits. And an AVR can only manage 8MHz on a good day.

Not when you consider that once you have loaded an 18 bit colour all you need to do is toggle the T_CS pin at say 10MHz and you can load the same pixels sequentially at 10Mpixels/s (=180Mbps) i.e. clear the screen faster than it is refreshed. With SPI you have to keep serially sending the same pixel N bits of colour over and over again, which is very inefficient. In the worst case (where sequential pixels are different colours) the shift register still wins if you can clock it faster than an SPI link maximum rate (easy on higher performance computers) because the same number of bits need to be clocked whatever interface is used.

This suggests more control bit are shifted in than is actually needed, but my hunch of an 18 bit + control parallel interface to the TFT seems to be correct.

That aside, I sort of assume I"ll need a 3,3V logic converter, since the rpi has 3,3v GPIO pins and most arduinos have 5V? So I don"t accidentally burn out the display chips.

Yes, I expect that bodmer or myself could probably get you working if we made some inspired guessing with the schematic. You could always email Kedei and ask him for the genuine schematic. Make sure that you tell him the Revision number(s) on the pcb.

I had success with downloading Kedei"s 4GB images specific for the 6.1 board and putting on an SD card. Now the raspi boots up, and I see the boot messages scroll by. The original article said "expect about 6fps from the display" and that seems right - it"s jerky, but works.

I"m going to order a couple of logic level converters now (a pair of 74LVC245 should do nicely on a breadboard), and then I can poke at it from an arduino environment.

I"ve gotten the level converters now, and experimented a little, with no results but a plain white screen. I copied the "init commands" code from the Linux source for ILI9341, which are the closest thing I could see in the patch made by KeDei for any init-code, plugged an arduino Uno in via a level converter from 5v down to 3v3, with SCK/MOSI/MISO from arduino pins 13/12/11, and pin 9 to toggle L_CS, keeping it HIGH but pulling it LOW for 1 to 5 milliseconds after each 4-byte SPI write.

Eventually I tried without the level converter too, since the 74HC595 datasheet said it could handle "up to Vcc" on the input pins, Vcc being max 6V. But that was after trying a lot of combinations in the code; all the variations of SPISettings in Arduino"s SPI library, for transferring four bytes one at a time (someone else who also looked at these displays found out that the registers always want four bytes - and that the first byte is always 0x0 !). Also doing as you suggested with an extra "DC command bit" so that the "bytes" were 9-bits wide, ending in a zero bit to indicate "command". No luck, ah well.. And I can"t even be sure that either the display is an ILI9341 just because the sales page said so (others had gotten similar displays with another drive chip), or that the code in the kernel source matches this KeDei-version of the display.

This is a modified version of the official PJRC ILI9341_t3 library (https://github.com/PaulStoffregen/ILI9341_t3) to work with KeDei Raspberry Pi displays.

And it is always a Work In Progress. Also using a lot of work from the the Raspberry Pi implementation: https://github.com/cnkz111/RaspberryPi_KeDei_35_lcd_v62

This library was created to allow extended use on the KeDei Raspberry Pi display and supports T3.5, t3.6 T4 and beyond. It also has support for other T3.x boards as well as TLC.

Your SPI communications on this board does not go directly to display but instead go to three shift registers. There are also two SPI Chip select pins, one labeled, which looks like it is for the Display and the other looks like it is for the touch controller. This is partially true.

However the SPI communications with the display are a lot different than any other I have seen. For example there are no reset pins, nor a Data/Command(DC) pin. Instead this information is encoded into the SPI data that you send to the display.

We figured it out, as the RPI startup code, did several strange SPI transfers at the beginning, which appeared like they were directed to the XPT2046 Touch controller.

This library borrows some concepts and functionality from another ILI9341 library, https://github.com/KurtE/ILI9341_t3n. It also incorporates functionality from the TFT_ILI9341_ESP, https://github.com/Bodmer/TFT_ILI9341_ESP, for additional functions:

The teensy 3.6 and now 3.5 have a lot more memory than previous Teensy processors, so on these boards, I borrowed some ideas from the ILI9341_t3DMA library and added code to be able to use a logical Frame Buffer. To enable this I added a couple of API"s

Place the Adafruit_ILI9341 library folder your arduinosketchfolder/libraries/ folder. You may need to create the libraries subfolder if its your first library. Restart the IDE

However changing the size of the table from const unsigned char font16_B[96][16] to const unsigned char font16_B[96][8] means that the characters displayed on the TFT screen will be smaller.

Using Preprocessor directives to select the font table to use and selecting a subsection of the file font8x8_basic.h from Hepper"s GitHub repository, I added the following to the KeDei TFT library.

I have forked the KeDei TFT library source code from Osoyoo"s GitHub and have begun modifications to the source. The fork is located at https://github.com/RichardChambers/driver/tree/master/KeDeiTFT

In order to support the number of buttons, I rewrote the Button class so that I could have buttons which share some data thus saving about 11 bytes per button. So this GUI with eight buttons that are using the data sharing feature saves some 77 bytes of memory, a significant saving for an Arduino.

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.

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.

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 designed this case so I could have the TFT35 screen from a Raspberry Pi on the front of my Ratrig V-Core 3. ...It will probably fit other extrusions but it was designed to sit nicely on 3030 extrusion that the Ratrig has.

I designed this case so I could have the TFT35 screen from a Raspberry Pi on the front of my Ratrig V-Core 3. ...It will probably fit other extrusions but it was designed to sit nicely on 3030 extrusion that the Ratrig has. Print Settings Printer:...

3.5 inch TFT LCD touch screen waveshare. ...Arduino Shield.assembled in a bracket with M2x8 screws and M2-IUTB-inserts.Designed By Alon Rahamim from Trixel Engineering.

It also hold a 3.5 Inch TFT Screen. It is made of nine 3.25mm pieces that all connect with four - 3mm screws. Its very easy to print and assemble. Print each piece in any color you want and then just assemble in order 1 through...

This is a slightly tilted (and upright version included) holder for an Arduino mounted ILI9488 3.5" TFT display with touch and TF card reader. While not a complete enclosure, it looks a bit more elegant and is a bit more short-out-safe than having...

Since I switched to klipper and didn"t feel like figuring out the stock screen, I ended up using a Kuman 3.5" tft and a Pi3b+ for my klipper conversion.

Simplified model of a 3.5 inch LCD for Raspberry Pi. ...I used the usb connectors from this model: Raspberry Pi 3 Model B Reference Design Solidworks CAD Raspberry-Pi Raspberrypi Rpi

Fit an [Adafruit 3.5" TFT LCD touchscreen](https://www.adafruit.com/product/2441) [Octopi rig](https://octoprint.org/) in the front panel of the [Prusa i3 Mk3](https://www.prusa3d.com/original-prusa-i3-mk3/), keeping it centered on the printer...

Lerdge 3.5 inch screen Features:Add all-inclusive steel frame for the touch screen, more stable.The motherboard adopts resistance to touch, man-machine interaction provides a variety of options.High-resolution of 480*320.Support high-speed hardware...

This is enclosure for [Mellow FLY TFT V1 3.5 inches](https://aliexpress.com/item/1005004091787313.html). ...The enclosure was designed for Ender 3 printer.

Pi TFT plus Console Case for 3.5 Inch Displays Some additions for using displays without mounting holes: The support frame to place between Display und PI to give the display a better foundation then the connector plug alone could give (fits tightly...

Screen used is KeDei 3.5 inch LCD TFT 320x480 touch screen (sample link https://www.aliexpress.com/item/New-Original-3-5-Inch-LCD-TFT-Touch-Screen-Display-for-Raspberry-Pi-2-Raspberry-Pi/32851565266.html). ... You will need: - The screen (KeDei 3.5 inch...

This is a case for Raspberry Pi 4 with 3.5 inch TFT/LCD Display. It is a tight fit and may require some wriggling to fit the PI in. ...This is a very simple and a sleek case.

ER-TFTM050-3 is 5 inch tft lcd module WVGA 800x480 display,serial,spi,i2c parallel interface,RA8875 controller,capacitive or resistive touch screen panel.Souce from EastRising/buydisplay.com

I designed this stand frame for my new 5 inch CTP screen. It"s this one: JLT Technologies JRP 5008 https://es.aliexpress.com/item/1005002280377732.html Use some M3 screws to hold it. I put some auto adhesive small rubber feet to prevent slipping....

I"ve designed this and use it for holding this screen: http://www.banggood.com/FPV-4_3-Inch-TFT-LCD-Monitor-Screen-For-RC-Models-p-940817.html on my Turnigy 9X remote.

Are are links to the hardware: * [kuman for Raspberry Pi 3B+ TFT LCD Display, 3.5 Inch 480x320 TFT Touch Screen Monitor for Raspberry Pi Model B A+ SPI Interface with Touch Pen SC06](https://amzn.to/33aILS4) * [CableCreation [2-Pack] 3.2 feet Right...

This is a slanted box for compact projects incorporating a 3.2" TFT display such as this one which can be found on Aliexpress and many other places for about $USD8: https://www.aliexpress.com/item/32960934541.html I typically use a daughter card...

The display support comes before the assembly on the RJ45 connection. As a touch screen, I use the Elegoo Display 3.5 "inch TFT LCD touch screen monitor 480x320 for Raspberry Pi.