Need a little help, Mega2560 shield TFT 3.5" display with a Teensy 4.1

L

Lisfin

New member
I have a TFT display shield that plugs directly into the Mega2560 and it works, however it seems slow updating where there is a slight "flash" of the text updating. So I purchased a teensy 4.1 which looks like its 100x faster!

TFT Mega display.PNG

Can anyone tell me how to wire this up to a Teensy 4.1? I understand the code as I have years of programming, but I am not a electrical engineer and struggle with the pinouts from Teensy to the display. I have tried a few different libraries and different pins over a few days but I am getting frustrated and could really use some help. A few things I am kinda confused on.

1. Would SPI work on this display, only requiring a few wires?
2. What pins are the MISO, MOSI, CLK on the display?
3. Are the SD pins used even if there is no SDcard?
4. When the code requires the reset pin, do you use LCD_RST or RESET on the display?

I have read and looked around a lot on these forums and have seen many different examples, however there are always slight differences that seem to hang me up. I think I am getting hung up on the pinouts to the display which is why its not working for me. A little help would be greatly appreciated and thanks very much for your time!
 
Sorry maybe need link to page that describes this display.

It looks like it may use parallel inputs, which is a little more difficult.
 
You can use FLEXIO3 on the 4.1 and drive it in a polling method as #3 has no DMA support.
But you are going to have to write the entire library.
You can look at my simple 8 bit parallel display driver with DMA support for the teensy MicroMod here and copy some of the code.

I don’t have much spare time on my hands right now but I can do my best to try and assist.

What is your goal with this project? What other peripherals are you using on the Teensy (SPI, I2C, CAN, Serial etc) and for what?
 
Thanks much you guys, any and all help is appreciated. I am trying to convert from the mega 2560 to the Teensy 4.1. The mega is sadly too slow which I did not know when I was getting into Arduino dev. I am using it to create a air quality sensor that gets Co2, Particle size/count, Temp, Humidity. I have it working with the mega and it displays all the data, however when it refreshes the text there is a slight flicker during the update. I have tried writing code so it will only update the text that has changed and not the whole screen, the text still has a slight flicker to it though. I was collecting the sensor data though the i2c pins on the mega...I have 2 of each sensor and then average the results to make it a little more accurate. I also have some multiplexers so I can call each sensor if I have limited pins.

It works but as a slight perfectionist the flicker drives me nuts lol. I seen the benchmarks for the teensy and was extremely impressed with its speed and wanted to port my code over to it. Mega poop, Teensy vrooom.
CoreMark-Performance-Chart-2.jpg

@KurtE It is probably a knock off I found on Amazon for cheap when it was on sale...the link to it https://www.amazon.com/2-8-3-3V-Display-480x320-Resolution-Arduino/dp/B07HFBF221?th=1

@Rezo thanks for the information, I will look into this and see what I can find out.

Thanks for your time and responses, I appreciate the help. If needs be I might just buy a display that is more compatible, what 3.5" display (with touch would be great) would you guys recommend for the 4.1? AND have a great weekend!
 
To keep things simple, I would go with an ILI9488 in SPI mode or an HX8357 from Adafruit
Both have supporting libraries for the Teensy, and you can get them up and running quickly with good performance.
 
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