How to Connect ITEAD 2.8” TFT to Teensy 3.6?

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ohthepain

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I am trying to learn Teensy and get my ITEAD ITDB02 v1 2.8” TFT working at the same time.

How do I figure out which pins on the shield connect to which pins on my Teensy 3.6? Specifically, which pins on the teensy should shield pins DB8-15 go to?

I have checked the 3.6 schematic against the data sheet for the shield, but I couldn’t figure it out. I'd love to find an introduction that explains the hardware basics to experienced coders.
Cheers!
 
Ouch... probably not the best idea to use a display with parallel interface. The highly optimized IL9341 graphic libraries for Teensy MCUs are (if I remember correctly) best with displays driven via the SPI bus. But this ITEAD display has SPI only for the SD card, not for the display itself.
Quick solution: take a different display for which high speed Teensy libraries exist, for example this one: https://www.pjrc.com/store/display_ili9341_touch.html (it’s even cheaper)
Academic solution: write your own library for your display. A good starting point is this library which has been written for another 8bit parallel display with ILI9341 controller IC: https://github.com/LudumDareDevelopment/Teensy-ILI9341-8-bit-Parallel-Library
 
Can’t tell. Adafruit sells hundreds of different displays with different specifications, but this website does not tell which type it exactly is. They do not link a datasheet, nor to a wiring diagram, they don’t tell which controller chip and which bus type is used. They just tell that it could somehow work with Raspberry Pi MCUs. Not serious at all, that website.
I fear you’ll have to make an international order to get something reliable. And in that case, you might go directly for the PJRC display which has proven to work with the Teensy and for which there is an excellent library and forum support.
 
Thanks for your responses!

The controller is the HX8357. Does that help?

I did manage to find a data sheet for the controller:
https://cdn-shop.adafruit.com/datasheets/HX8357-D_DS_April2012.pdf

More info here:
https://learn.adafruit.com/adafruit-pitft-3-dot-5-touch-screen-for-raspberry-pi/downloads

Ordering from the states take weeks, and I am off this week. There's no point in this hobby if I have to order from the states. But if this screen works then I can go down the street and pick it up today and start coding for it. Woo hoo!
 
Ok, I’m out of this thread... Since Adafruit intends this display to be used with a Raspberry Pi MCU and not with a Teensy, they don’t publish the needed technical details or libraries for use with the Teensy, thus I can’t take the responsibility to acknowledge if this display can be made working with the Teensy. Why do you insist on putting a Saab motor into a Volvo car? Use Saab motor with Saab cars, and Volvo motor with Volvo cars.

Technically, there is almost always a way to make things somehow work together, but that depends on the individual engineering and coding skills on an individual. I’m sure that one can (perhaps with degraded performance) make the ITEAD or the Adafruit Display make work somehow with a Teensy, but that could take much longer than ordering a known working display from overseas and I’m not sure that the volunteers here in these forums find it meaningful to spend time in supporting such an uncertain approach.
 
I agree with @Theremingenieur that it is most likely possible. But not sure how much support you will find for it. If it were me, I would look at the Adafruit page: https://learn.adafruit.com/adafruit-pitft-3-dot-5-touch-screen-for-raspberry-pi/downloads

Probably from there go to their board design files (eagle): https://github.com/adafruit/Adafruit-PiTFT-3.5-Plus-PCB

And then look at all of the schematic... Which I printed to a PDF file:

I would then have to look through each of the IO pins to figure out which pins logically might go to which Teensy pin. Example, there are SPI pins... There is an STMPE610 touch controller, which there is an Arduino library for... You would then need to look or create Arduino library to talk to the TFT chip controller, which again looks like SPI with CS and DC pins... Not sure how much different than some of the other controller code...
 

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Thanks, I have looked into it and agree with you guys that it does look complicated and I would definitely need a lot of help.

Is there a list of displays that are known to work with Teensy 3.6? Or can anybody recommend a touch screen that I might be able to get sooner here in Sweden? Big plans for my week off! = )
 
ohthepain said:
Thanks, I have looked into it and agree with you guys that it does look complicated and I would definitely need a lot of help.

Is there a list of displays that are known to work with Teensy 3.6? Or can anybody recommend a touch screen that I might be able to get sooner here in Sweden? Big plans for my week off! = )
Click to expand...

I can't give you a list, but can say that this one works very well with Teensy 3.5
 
ohthepain said:
Thanks, I checked it out. Is it slow? In adafruit's product video they say it takes a second refresh the screen.
Click to expand...

I'm in the same boat as you, going to attempt to get HX8357 working on teensy 3.6. I believe the adafruit display linked above is the same display used as a feather wing: https://www.adafruit.com/product/3651

I'm using the arduino feather with this HX8357 right now, but refresh rate is slow(~500ms for complete redraw). I believe this is due to feather spi limitations and adafruit library limitations. My hope is teensy will dramatically improve refresh rate.

Long story short... the display is not limited to raspberry pi only. Adafruit has arduino library support for this driver
 
It comes to simple computation. If you have 320x480px at 16bit color, 2,457,600 bits have to be transferred for a full screen refresh. Divide the maximum SPI clock which the display can do (or which the Teensy can do) by this number and you get the approximate refresh rate in fps. Even at a very high SPI clock of 24MHz, the (full) refresh rates will remain below 10fps, independent of the Teensy or the display controller IC.

Thus, it all comes down to intelligent programming, avoiding full screen refresh but meticulously targeted and well thought partial redrawing where needed.
 
I will order the PJRC one and pick it up when I am in the USA later in March. 10fps is fine for my UI purposes, and I am still very excited for this display.

For the meantime I picked up a 4x20 HD44780 display, which is working fine for now.

Thanks everybody for your help here!
 
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