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Thread: I would like a 3.5 inch 480x320 touchscreen display!

  1. #1
    Senior Member Projectitis's Avatar
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    I would like a 3.5 inch 480x320 touchscreen display!

    Hi people - first post here. I'm a long time tinkerer, but new to teensy. Really enjoyed dabbling (software side) on GamePark GP32 and Wiz a few years back, and finally now getting back into things with a platform that is more widely used!

    I'm really keen on a larger (320x480, 3.5"+) display like the one mentioned in Paul's post - How about a 3.5inch 480x320 touchscreen display.
    I've got a Teensy 3.6 on the way. After a lot of reading, I'm pretty sure I want a display with SPI.
    There have been lots of different controllers mentioned - RA8875, HX8357D, ILI9481, ILI9488, SSD1963

    As you can likely tell I have next to zero experience with displays apart from what I've read over the past week or so. I'll most likely buy a display from AliExpress to start with (getting anything else in New Zealand tends to be quite expensive). Whats my best bet for a display that has the most chance of success of working? What should I look for?

    Any help appreciated!
    Peter

  2. #2
    Senior Member Projectitis's Avatar
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    I'm thinking of something like this ILI9481 display (with no touch).
    Or maybe one of their other ILI9481 displays might be better suited?

    Appreciate any help/advice I can get!

  3. #3
    Senior Member PaulStoffregen's Avatar
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    Quote Originally Posted by Projectitis View Post
    Appreciate any help/advice I can get!
    This probably isn't the answer you want, but honestly, the slightly smaller 320x240 ILI9341 displays with 4 wire SPI are the best supported, using the ILI9341_t3 library. If you go with anything else, you really should expect quite a lot of work and effort required.

    For those parallel interface displays, you'll probably use the UTFT library. Be aware that you need to connect *many* wires. The 16 bit ones end up consuming nearly all the pins on a Teensy. It's a *lot* of wires to connect. If any wire isn't right, the whole thing is dead and usually the only way to troubleshoot is double checking your wires. Many people have gone down that path and been terribly frustrated when they made a wiring mistake they couldn't find (it's a natural human tendency to overlook the mistake over and over until sometime else checks every wire).

    Hardly any serial interface 480x320 displays exist, because it's so many pixels to try controlling. There aren't any highly optimized libs like ILI9341_t3 (or at least not any I personally know about) which means you'll probably end up resorting to something like one of Adafruit's libs, which work but can be terribly slow.

    I highly recommend getting the well supported ILI9341 display. It's still quite a lot of resolution. Get that up and running first, so you have something that works before you start the long and likely painful journey of going with a poorly supported display.

  4. #4
    Senior Member Projectitis's Avatar
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    Appreciate your reply, Paul, and understand totally what you are saying. I don't actually mind a bit of work and frustration trying to get a larger display to work - if I'm successful it'll help out anyone that wants to use a larger display

    I'm a bit worried about your comment regarding parallel interface displays, though. The display I linked to says "Interface: SPI Serial + RGB Interface". I was under the impression that that meant I could use either - but does that mean it's somehow a combination of both and will consume a set of SPI pins as well as all those required for the parallel RGB interface?

    As an aside, do larger 320x240 ILI9341 displays exist - i.e. 3.2 inches or more (with larger pixels, naturally)?

  5. #5
    Senior Member PaulStoffregen's Avatar
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    I have limited experience with other displays. (that's a theme you'll probably get used to hearing....)

    Many of the controller chips have 3 or 4 pins which configure the type of interface, like 3-wire & 9 bit SPI, or normal 4 wire SPI, or 16 bit parallel, or 18 bits, or other modes. The chips are similar, but with minor differences. Whether any particular display brings those pins to the user, either on the flex-PCB or the rigid PCB (if it has one) is a good question. Many times those pins are hard-wired to one setting and you can't easily change.

    Again, this stuff varies between chips & displays. Everything I've said might not apply to any particular display. You're going to have to check the (usually incomplete) info from the vendors, or ask them for help. These are their products, afterall.

    Exactly what products exist changes pretty rapidly, so there too, you're going to have to do your homework and ask question from the vendors if the info isn't clear. The reality of Aliexpress is low prices but low expectation of quality & service. Buying anything on Aliexpress always involve some risk. Often it pays off, especially when buying something very common where you already are very familiar with how it works. Sometimes things don't work out as well. Maybe others will comment with their success or fails from Aliexpress.

    The best advice I can tell you is PJRC mainly supports ILI9341 with a highly optimized library. Even if you try something else, I highly recommend *also* using ILI9341 so you can compare and have something that works well with good performance while you (maybe) suffer frustration with something else.

  6. #6
    Senior Member Projectitis's Avatar
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    Thanks Paul, good advice. I'll get my stuff working with ILI9341 first. That'll at least allow me to progress reasonably quickly and have something to work in between bashing-my-head-against-the-wall sessions with a larger display.

    This will be my 89th order on AliExpress, so I'm familiar with the quality expectations :P
    I'll hit up the vendors regarding their displays and see if there is more info available - I'm of course interested in using the least amount of pins possible, so 4-wire SPI sounds ideal (if it's available in a display this large).

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    Another source for displays is Buydisplay. Their prices and delivery times are competive with Aliexpress and they have downloadable documentation for the controllers and touch screens.

  8. #8
    Senior Member Projectitis's Avatar
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    Awesome - thank you! I just assumed it was US-based. I shouldn't assume...

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    Senior Member Projectitis's Avatar
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    Wow, BuyDisplay is waaaaay better than AliExpress for displays. Now I'm looking at this ILI9488 display (4-wire SPI, capacitive touch) which I'm pretty sure is the same one Paul purchased for his testing last year.

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    The last time I bought from them the delivery was fairly quick, maybe 10 days or so.

  11. #11
    Senior Member+ MichaelMeissner's Avatar
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    Another thought is somewhat of a kludge. If you need a bigger display (5-7"), and are primarily doing simple things on the display, it might be simpler to get a Raspberry Pi Zero (or Zero-W) to drive one of the various HDMI displays already supported for the PI, and communicate with the Teensy via serial port and/or i2c. You would need to be able to program both the Pi and the Teensy, and create a simple protocol to send stuff from the Teensy to the display, and possibly send back touch information. That way, you don't have to create the infrastructure for a display.

  12. #12
    Senior Member Projectitis's Avatar
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    That's a good thought, Michael I've seen another project where that exact thing was done - Alexis Boisserand's wooden handheld game console. My eventual goal is actually to do the same thing (handheld game console) but powered completely by teensy

  13. #13
    Senior Member Projectitis's Avatar
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    I have two displays on the way from BuyDisplay - a 240x320 ILI9341 and a 320x480 ILI9488, both with 4-wire SPI and capacitive touch, and both around the same size (3.2" and 3.5").

  14. #14
    I've had a lot of fun with the ILI9341 displays as well. https://youtu.be/RK0VyQ14qFc that one is a 2.8 inch one from adafruit.

    Now I'm playing around with a gameduino3 http://excamera.com/sphinx/gameduino3/ on a teensy 3.6 which is a lot of fun. It uses a 4.3 inch screen and a FT810 which is a gpu with 1mb of ram. The teensy connects to it over SPI and sends display commands.

  15. #15
    Senior Member Projectitis's Avatar
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    Wow, very cool! Do the controllers come off, or did you just style it after the switch? I have the exact same PSP thumb sticks on the way (along with tons of other buttons and goodies) from AliExpress.
    The gameduinio 3 looks amazing. I think I can see another purchase on the horizon...

  16. #16
    The controllers are stuck on there :-) I only made the case kinda look like a switch. Here are some pics with the case off: https://forum.pjrc.com/threads/47248...l=1#post159619

  17. #17
    Senior Member Projectitis's Avatar
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    Wink

    My displays have arrived from BuyDisplay. Can't wait to get stuck in over the next week or two. Unfortunately no time this weekend
    This is what I got:

    LCD 3.5" 320x480 TFT
    IC: ILI9488
    Interface: Pin Header Connection-4-Wire SPI
    Power Supply (Typ.): VDD=3.3V
    Touch Panel: 3.5" Capacitive Touch Panel with Controller

    240x320 Touch Screen 3.2" TFT
    IC: ILI9341
    Interface: Pin Header Connection-4-wire SPI
    Power Supply (Typ.): VDD=3.3V
    Touch Panel: 3.2" Capacitive Touch Panel

    Click image for larger version. 

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    Click image for larger version. 

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  18. #18
    Heya Projectitis,
    It looks like you found a 3.5" display already. If you encounter any difficulties, I was able to get the adafruit 3.5" HX8357 display working, with KurtE's help. (thanks Kurt)
    https://forum.pjrc.com/threads/50397...357_t3-library

    I was able to use the faster HX8357_t3 library, which can also use all the ILI9341_t3 fonts. Just some info if it helps your project. Cheers!

    https://www.adafruit.com/product/3651

  19. #19
    Senior Member Projectitis's Avatar
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    Awesome, thanks Willyman. Just waiting for some breadboard headers to arrive before I can get started, but glad you have yours working

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