Some help with connecting a display to arduino uno

Other Hardware Displays
1

Hey guys,

I recently got into arduino stuff and was trying to connect a LDC panel to the controller. The display I bought was:

(It is a SPI 20 pin which uses a ST7789V display driver)

I don't know if the problem is with my wiring or with configuring the proper drivers but I haven't been able to find much advice on the internet so was hoping for some help here. The way I have connected my arduino uno to the display is in the image attached.

Connections
Connections902×565 113 KB

Any help would be really appreciated.

Thanks!

2

Took a look at the "datasheet", specifically the pinout. I'm confused. SDA/SCL are IIC interface signal names. Yet they claim to be SPI? No MOSI, MISO, CLK, CS/ ? Others may know better. If it was me, I'd be contacting the seller for clarification, or an RMA.

3

Oh, and if it's SPI, then the pins on the Uno are usually D10,D11,D12,D13.

If it's really IIC, SDA/SCL are A5/A4, or the duplicate pins labelled SDA/SCL.

You'll have to show your code sooner or later.

4

Oh wow thank you, I'll ask the manufacturer for more guidance.

The code that I had was very basic:

#include <Adafruit_GFX.h>
#include <Adafruit_ST7789.h>
#include <SPI.h>


#define TFT_CS    10  // Chip select
#define TFT_DC    9   // Data/Command pin
#define TFT_RST   8   // Reset pin (or set to -1 if tied to Arduino RESET)


Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);

void setup() {

  Serial.begin(9600);
  Serial.println("Hello");


  tft.init(240, 320);


  tft.fillScreen(ST77XX_BLACK);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(2);
  tft.setCursor(10, 10);
  tft.println("Hello, ST7789V!");
}

void loop() {
  tft.fillScreen(ST77XX_BLUE);
  delay(1000);
  tft.fillScreen(ST77XX_RED);
  delay(1000);
  tft.fillScreen(ST77XX_GREEN);
  delay(1000);
}
5

Be careful, that display uses 3.3V logic signals, the 5V logic of the UNO may destroy the display.

6

I found a minimum of 10 pages of hits on google.

7

Sorry you may have already destroyed the display, the data sheet shows it is 3V3 not 5V on the SPI pins: https://docs.rs-online.com/ec01/A700000012198395.pdf

8

Really? I could only find things for the ST7789 driver but I read that there's a difference between that and ST7789V

9

Oh right, is there any way I could check to see if this has happened

10

Ok, so I did a google search on the ST7789V as well, and again, more than 10 pages.

11

Just load up a simple sample like Hello World if it exists.

12

Is this what your display looks like? If it is, what are you connecting to the flat cable, it has 20 connections, where are they attached to?

Screenshot 2025-01-24 at 12.18.45
Screenshot 2025-01-24 at 12.18.45528×774 40.3 KB

13

Could you let me know what your prompt was because I still can't find anything
Also I'll send a picture of the setup I have at the moment to show how I am connecting the display to the computer

20250125_002848
20250125_0028481920×3413 446 KB

14

Your picture doesn't help other than to tell me the odds of it working are very remote. Even if you got lucky and bought one of the 2 good breadboards, that many wires are unlikely to all make good contact at the same time.
If you can split the wiring into two parts. The display and it's 20 odd wires to one breadboard. Here is my Canadian Amazon LINK this is the small board for the display. Thenput the rest of the wiring on a normal size board like this one LINK then wire them together. It is still risky but that is your best chance.

15

Oh, I didn't know that was a thing.
I do have a separate smaller breadboard (it came as part of a bundle for some component I needed) so I'll try connecting to that and splitting up the connections so they jump across less breadboard rows.
I'll let you know how it goes.