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Thread: How can I tell if a TFT LCD screen is compatible with Teensy3.6

  1. #26
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    Not really enough free pins on most Teensy projects for even an 8-bit parallel interface!

    The only 3.5" SPI/SPI TFT boards I could find were designed for the RPi - and this library works OK with that.

    Here's a board similar to the one I have, which works with a T3.6:

    https://www.ebay.com.au/itm/3-5-TFT-...B/141932024322

  2. #27
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    Note: There are other 3.5" SPI displays with similar resolution, some that I have include:
    https://www.adafruit.com/product/2050 - Uses our HX8357 library.

    Some ILI9488 displays including:
    https://www.buydisplay.com/lcd-3-5-i...breakout-board

    Note: there are several listings on Ebay for these...
    https://www.ebay.com/itm/3-5inch-TFT...gAAOSwWG5egw00

  3. #28
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    I am not an electrical guy, so please be lenient towards me.


    Does any ili9486/88 spi Display work? Some chinese seller sell ili9486/88 spi displays, isn't there a difference between the controllers?

    Wanted to buy the Waveshare 4" model. This should work right? https://www.waveshare.com/wiki/4inch_TFT_Touch_Shield

    Is there a chance to make dma work on teensy 4.1 with the bigger displays? (512kb should be ennough when 3.6 with 256kb can run half the resolution?)

  4. #29
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    Quote Originally Posted by dslocum View Post
    THanks for the super quick reply! Not sure what happened to my post. POOF! :-(

    Actually, I was looking for the wiring for a Teensy 3.2, not an STM. I saw your #defines in the code, they didn't relate to the Teensy and my display which has different pin descriptions

    Anyway if it helps someone else, I managed to get it working using:

    Teensy 3.2 Display
    ------------------------------------
    13 SCLK
    12 MISO
    11 MOSI
    10 LCD_CS
    9 LCD_DC
    8 LCD_RST

    Cheers!
    HI - returning to this after several years.
    SO trying to get the OP TFT workinhg with a T3.2 again.

    Im so confused with all teh different labelling for teh various pins.
    SO can some mark the TFT pin number against the Teensy Pin Number pls

  5. #30
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    Sorry if it has been several years, not sure what TFT you are referring to? What labeling? ...

  6. #31
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    Quote Originally Posted by KurtE View Post
    Sorry if it has been several years, not sure what TFT you are referring to? What labeling? ...
    Kuman 3.5 inch 320*480 Resolution Touch Screen TFT LCD Display With Protective Case + 3 x Heat sinks+ Touch Pen for Raspberry Pi 3 Model B, Pi 2 Model B & Pi Model B+ SC11
    https://www.amazon.co.uk/dp/B01FX790...135791_TE_item

    Its the Dispay pin numbers Im after (not descriptions) pls.

    SO I know which Dispay pin number goes to what Teensy pin number

  7. #32
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    Im seeing things like

    TFT_CS LCD_CS
    TFT_RST LCD_RST

    which I assume are equivalent.

    But then
    TFT_RS
    LCD_DC

    are they equivalent?

    Sorry - probably quite simple - but just not getting it.

  8. #33
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    Again Sorry, I can not appear to get to that link...

    Is it this one: http://www.kumantech.com/kuman-35-in...c06_p0014.html

    If so no idea if it will work or not. It is for an RPI, so could be one of many different Setups with their own RPI driver. Might be lucky and be one that uses ILI9488 (or maybe ILI9486)

    Nto sure if RS is DC or not.. Maybe, but maybe not... Some like the KeDei display for RPI have a real screwy interface, using shift registers, and this may be similar...

    Sorry not sure without more information... You might try our KeDei driver or the ILI9488 driver or HX8357 driver... As all three have that resolution...

  9. #34
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    OK thanks.

    Per post #14 & 19 - I assumed these folks had already proved thsi display can work with Teensy.

    I will take a look at the Libs you have suggested - cheers

  10. #35
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    Quote Originally Posted by KurtE View Post
    Again Sorry, I can not appear to get to that link...

    Is it this one: http://www.kumantech.com/kuman-35-in...c06_p0014.html

    If so no idea if it will work or not. It is for an RPI, so could be one of many different Setups with their own RPI driver. Might be lucky and be one that uses ILI9488 (or maybe ILI9486)

    .
    BTW - looks very simialr to that one. But markings are slightly different.
    Mines does nt call out teh Touch COntroller XPT2046.

    Just says HVGA 480x320

  11. #36

  12. #37
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    Yes - it works. Still no details on what the actual interface is, so not sure...

    Good luck

  13. #38
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    If you read the questions and answers at the end of the amazon page it is this LCD
    http://www.lcdwiki.com/3.5inch_RPi_Display

    Features
    320480 resolution
    Resistive touch control
    Supports any revision of Raspberry Pi (directly-pluggable)
    Compatible with Raspberry Pi A, B, A+, B+, 2B, 3B, 3B+,4B versions
    Drivers provided (works with your own Raspbian/Ubuntu directly)
    Size perfectly fits the Pi
    High quality immersion gold surface plating
    Supports Raspbian system, ubuntu system ,kali Linux system

    Key Parameters

    SKU MPI3501
    LCD Type TFT
    LCD Interface SPI(Fmax:32MHz)
    Touch Screen Type Resistive
    Touch Screen Controller XPT2046
    Colors 65536
    Driver IC ILI9486
    Backlight LED
    Resolution 320*480 (Pixel)
    Backlight Current 120ma
    Power Dissipation 0.13A*5V
    Operating Temp. (℃) -20~60
    Active Area 48.96x73.44(mm)
    Product Size 85.42*55.60(mm)
    Package Size 118*72*34 (mm)
    Rough Weight(Package containing) 75 (g)

    Interface

    PIN NO. SYMBOL DESCRIPTION

    1, 17 3.3V Power positive (3.3V power input)
    2, 4 5V Power positive (5V power input)
    3, 5, 7, 8, 10, 12, 13, 15, 16 NC NC
    6, 9, 14, 20, 25 GND Ground
    11 TP_IRQ Touch Panel interrupt, low level while the Touch Panel detects touching
    18 LCD_RS Instruction/Data Register selection
    19 LCD_SI / TP_SI SPI data input of LCD/Touch Panel
    21 TP_SO SPI data output of Touch Panel
    22 RST Reset
    23 LCD_SCK / TP_SCK SPI clock of LCD/Touch Panel
    24 LCD_CS LCD chip selection, low active
    26 TP_CS Touch Panel chip selection, low active

    Driver Installation

    This LCD Module need install driver first.

    Step 1:Download the Raspbian IMG

    https://www.raspberrypi.org/downloads/raspbian/

    Step 2: Burn the system image

    If you don't know how to do that,you can refer to the Raspberry Pi office tutorial

    Step 3: Open terminal(SSH) and install the driver on RaspberryPi

    (tested on RaspberryPi 3B+,3B,2B,2B+,1B,ZERO)

    Run:

    sudo rm -rf LCD-show
    git clone https://github.com/goodtft/LCD-show.git
    chmod -R 755 LCD-show
    cd LCD-show/
    sudo ./LCD35-show

  14. #39
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    Quote Originally Posted by christoph View Post
    Yes, that combo would work. You can also buy a display module from China that includes a controller (iirc I bought one from buydisplay.com)
    Beware though. I'm not out to bash BuyDisplay, I've used many of their displays in my projects. Mostly the 3-inch ILI9341 display with xpt-2046 resistive touch and the 4.3-inch display with capacitive touch and the 5206 (?) touch controler which both worked very well. They also have other touch controllers such as the GSL1680 on their 5-inch RA8875 display. The display is super nice and the display drivers work well with it. It's the dang GSL1680 touch controller that has been a bear to get working, YES, I'm still trying. Some folks posted here that they got it working but I have had no such luck. So when you buy at BuyDisplay be sure to verify the touch chip you are getting. Besides that I do feel BuyDisplay is a good place to purchase displays. No bad feeling intended to other display vendors.

  15. #40
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    Yesterday, I wired the waveshare 4inch tft touch screen to teensy 4.1. One thing I had to change was the spi config on the display board. There are three switches to select the six pin spi connector or the outboard pins for spi.
    There is one issue that I have not looked into is the fact I have to connect the serial monitor before the graphics test will run. The pin numbers for the teensy 4.1 were identical to the mega or due.

  16. #41
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    Post your code and someone might be able to help.

  17. #42
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    Quote Originally Posted by pintoshine View Post
    Yesterday, I wired the waveshare 4inch tft touch screen to teensy 4.1. One thing I had to change was the spi config on the display board. There are three switches to select the six pin spi connector or the outboard pins for spi.
    There is one issue that I have not looked into is the fact I have to connect the serial monitor before the graphics test will run. The pin numbers for the teensy 4.1 were identical to the mega or due.
    In cases like this it really helps others to help you, when we have additional information. Things like what display is this. I suppose we could do a search to see what boards waveshare produces that happens to be 4". What library are you using?
    What sketch you are running...

    But if the main issue is that it won't run until you connect up the USB Serial monitor.

    Than it is likely the sketch you are running has something in it like: while (!Serial) ;
    Which waits forever for a serial monitor

    To resolve that in code you can either remove it. Or do like I often do something like: while (!Serial && millis() < 5000) ;
    Which waits up to 5 seconds for the serial monitor before it continues. This gives you some time to get it open and not lose output, but continues if you don't. Also this works mainly at start of program. More generic, is to do something like:
    Code:
    uint32_t start_time = millis();
    while (!Serial && (millis()-start_time) < 5000) ;

  18. #43
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    Click image for larger version. 

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    Code is no issue for me 35 year c/c++ programmer.
    I had to fix the example supplied with the library from waveshare. The SPI was using sendBytes instead of transfer.

  19. #44
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    https://www.waveshare.com/4inch-tft-touch-shield.htm
    I believe this will provide enough information.

  20. #45
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    So it looks like it is an ILI9486 display: https://www.waveshare.com/wiki/4inch_TFT_Touch_Shield

    Looks like you have some stuff running. Not sure if we have adapted some of our other libraries like the ILI9488_t3 library to work with it or not... I know some have done with either this one or ILI9481_t3... library
    I don't remember if this one in SPI mode uses 18 bit colors 666 (24 bits to SPI) per pixel or if it can use the 565 16 bit color like many of our displays do. The 88 can only do this in parallel mode.

  21. #46
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    https://www.youtube.com/watch?v=RnDwhczVmj4 better quality https://youtu.be/-awU1vFeB2c
    This is a short video of the demo to display BMP files from the built in ssd card slot.
    These demos at https://www.waveshare.com/wiki/File:...Shield_Code.7z
    require a couple of repairs as far as finding fonts, casting a couple variables and fixing some string constants but operate correctly on the teensy 4.1.
    I added a few of my own images from a control gui I created a few years ago. I draw my gui backgrounds with inkscape.
    There are no additional libraries needed with the examples. They coded all the hardware interaction in the demo. It is delightful to see this example compiles to a mere 34KB
    Last edited by pintoshine; 11-15-2020 at 11:01 PM.

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