TFT LCD ST3375 only shows backlight on Arduino Mega

Hi,
I set up TFT LCD ST3375 display with Arduino Mega as described here connectst7735 · olikraus/ucglib Wiki · GitHub and it only shows backlight.
My display has only 8 porta so is not exactly the same as in tutorial, but driver is ST3375.
Here is a wiring scheme (from left to right on LCD):
LCD - Mega 2560
VCC - 5V
GND - GND
SCL - 52
SDA - 51
RES - 28
DC - 53
CS - 22
BL - 220 ohm - 5 V
Here is a code
#include <SPI.h> #include "Ucglib.h" Ucglib_ST7735_18x128x160_SWSPI ucg(52, 51,/*cd=*/ 53 , /*cs=*/ 22, /*reset=*/ 28); void setup() { delay(1000); ucg.begin(UCG_FONT_MODE_TRANSPARENT); ucg.clearScreen(); } void loop() { ucg.setPrintPos(10,10); ucg.print("Hello World!"); delay(1000); }
I linked SCL and SDA so hardware connection also works and tried to user Ucglib_ST7735_18x128x160_HWSPI but still no luck.
I also tried to link SCL, SDA, RES, DC and CS using 1k resistors to particular MEGA 2560 pins (saw in other tutorials), but still no luck.
Here is the image attached.
I'm using library version 1.5.2 on Arduino offline IDE version 1.8.13.
Can you please help? If maybe UCG_FONT_MODE_TRANSPARENT creating a problem? Or maybe connection between LCD pins and pins is loose, since it is not soldered. I'm just experimenting with LCD...
Thanks in advance,
P.S.: I know that the same topic exists here https://forum.arduino.cc/index.php?topic=257229.0, but it was never resolved.

Disconnect that screen right now!

You must be careful to read the information on your screen well, upload a link in which we can see the exact model you have. A photo of the back can also be used to see the circuit and give you a better idea

The new versions of ST7735 are coming out with 3.3V logic, if it is your case it is solved with a CD4050BE or 5V -3.3V voltage dividers in the SCK, CS, DC, Reset and mosi control lines

All works now.

This assumption was correct:

"Or maybe connection between LCD pins and pins is loose, since it is not soldered. I'm just experimenting with LCD...

Since pins on LCD was not soldered to its inputs, it was losing contact. As soon as I fixed it, all started working fine. Now I see my text, image, anything I write :slight_smile:

Thanks for answer.