ST3375 only shows backlight on Arduino Mega

[amerpersonal]

Hi,

I set up TFT LCD ST3375 display with Arduino Mega as described here https://github.com/olikraus/ucglib/wiki/connectst7735 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 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?

Thanks in advance,

Amer

[amerpersonal]

@olikraus any comments please?

[amerpersonal]

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 :)

This is solved. Maybe this topic will help to someone....

[olikraus]

👍