Using Waveshare 1.14" w/Teensy 4.1

markometer

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Just received my first Teensy 4.1, and seem to be having some nooby issues setting up a display screen on this thing. I was hoping for more plug and play but apparently my thick brain isn't comprehending the correct pin setup/library to use. I have a Waveshare 1.14" LCD using SPI. I've tried every combination I can think of but all I get is the backlight. I've tried using simple examples using both the Adafruit_ST7789.h with its helper libraries and also the ST7789_t3.h as mentioned in another post. The sketches load and run, but no display action at all. I have no other modules attached, so it shouldn't be too difficult to get a display to pop on. I'm just not having any luck. Attached is a photo with what I thought should be the correct pinout.
Any advice on what to try next?
 

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Welcome to the forum.
You may want to share more and higher resolution pictures. I tried to see where the wires go from the display to the Teensy, but it's not discernible.
Please share a schematic and your simplest code that shows the issue. Another few questions:
[1] What is the exact partnumber of the display? plus a link to the Waveshare site
[2] Which version Arduino IDE and Teensyduino are you running?
[3] Are you powering the setup from USB?

Please be aware that there may be forum members that have your hardware also available and would like to test, but you need to supply all the relevant data possible.

Paul
 
Yes it would be helpful to have the code. I don't have that display, but the pins are:

  • VIN -- connect to the Teensy 3.3v (on a few rare displays connect to VIN instead of 3.3v);
  • GND -- connect to the Teensy ground pin;
  • DIN -- connect to pin 11;
  • CLK -- connect to pin 13;
  • CS -- this can be any digital pin that isn't otherwise used;
  • DC -- Like CS, it can be any digital pin that isn't otherwise used (including the CS pin);
  • RST -- Like CS and DC, it can be any digital pin that isn't otherwise used (including the CS and DC pins); (and)
  • BL -- Generally connect this to 3.3v, but if you want to control the brightness of the backlight, you would want to connect it to a PWM capable pin and use analogWrite to control turning the back light on/off.

There are some things you may need to adjust in the examples:

  • Which pins are used for CS, DC, RST, and possibly BL;
  • The height/width of the display;
  • There may be an initialization flash which you might need to use (there was a flag for the older ST7735 displays, but I don't recall if the ST7789 displays still have this and possibly the rotation used on the display); (and)
  • There are some SPI related fields that we can try changing (SPI bus speed, SPI mode) if need be.
 
Is this the specific display you're using? (found by a quick Google search, since you didn't give any link or part number or SKU)


As PaulS mentioned, your photo is not good enough for anyone to really see how all the wires connect. But I did try, and the first thing I noticed is the display has a connector and cable with 8 wires, but I can see only 7 wires connected to Teensy 4.1 (including the blue or purple which is mostly hidden behind the orange wire due to poor camera angle).

Please show better photos. We can help more when we're able to actually see.

Also say clearly EXACTLY which programs you ran. Give a link to the library if not one of the libraries that comes with Teensyduino, and say specifically which example you ran. If you edited the example code in any way, copy the complete code into your message. Don't omit info, because if can't see what you actually did, then we have to guess and guesswork must less effecting at helping solve your problem.
 
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