Can't get ST7735S 0.96" 160x80 display to work correctly

[bsdinis1]

Hi, I've got two of these displays, one is black PCB and the other is blue PCB.
When I tried the one with the black PCB it worked correctly everytime without any problems.
Now I've soldered the display with the blue PCB to an ESP32 and I'm having trouble getting it to work correctly, I keep hitting the RST button but >95% of the time it won't display anything at all, if I'm lucky I might get the first screen in the sketch and then back to black screen again. I got this display to run the whole sketch once or maybe twice.
I've noticed that having the USB cable connected to the ESP32 gives it a higher chance to display at least the first screen in the sketch before blacking out.
I'm using 22AWG tinned copper silicon wires as short as possible and both PCBs are insulated from the protoboard with a layer of electrical tape.

#define USER_SETUP_INFO "User_Setup"

#define USE_HSPI_PORT

#define ST7735_DRIVER

#define TFT_WIDTH  80
#define TFT_HEIGHT 160

#define ST7735_GREENTAB160x80

#define TFT_DC 12
#define TFT_CS 15
#define TFT_MOSI 13
//#define TFT_MISO -1
#define TFT_SCLK 14
//#define TFT_BL 4
#define TFT_RST 2

#define LOAD_GLCD   // Font 1. Original Adafruit 8 pixel font needs ~1820 bytes in FLASH
#define LOAD_FONT2  // Font 2. Small 16 pixel high font, needs ~3534 bytes in FLASH, 96 characters
#define LOAD_FONT4  // Font 4. Medium 26 pixel high font, needs ~5848 bytes in FLASH, 96 characters
#define LOAD_FONT6  // Font 6. Large 48 pixel font, needs ~2666 bytes in FLASH, only characters 1234567890:-.apm
#define LOAD_FONT7  // Font 7. 7 segment 48 pixel font, needs ~2438 bytes in FLASH, only characters 1234567890:-.
//#define LOAD_FONT8  // Font 8. Large 75 pixel font needs ~3256 bytes in FLASH, only characters 1234567890:-.
#define LOAD_FONT8N // Font 8. Alternative to Font 8 above, slightly narrower, so 3 digits fit a 160 pixel TFT
#define LOAD_GFXFF  // FreeFonts. Include access to the 48 Adafruit_GFX free fonts FF1 to FF48 and custom fonts
#define SMOOTH_FONT

#define SPI_FREQUENCY 60000000
//#define SPI_READ_FREQUENCY 20000000

[Bodmer]

CS and RES (reset) are not connected so will "float" to a random logic level unless biased. Connect them to 3.3V or drive with a GPIO pin.

[bsdinis1]

that was it. thank you. CS only wasn't enough I had to solder both CS and RST

[bsdinis1]

what is the maximum SPI frequency for this driver IC?
at 80000000 I get white squares all over the screen but if I reduce to 79999999 and it runs the Draw_Smooth_Circles sketch just fine, but while running the Bouncy_Circles sketch the screen tears like it's divided in 3 parts at 60000001 but if I reduce it to 60000000 it runs just fine.
so I guess the maximum SPI frequency for my particular display is 60MHz?

[Bodmer]

I usually find 27MHz is maximum but it is supplier and batch dependant so it is a case of try it and see if there is any image corruption.

[bsdinis1]

I wired the display D/C pin to the MISO pin of the HSPI port, it seems to work fine but is the library using Hardware SPI or Software SPI with this pin arrangement?
And would having the D/C pin on the MISO line cause any issues if I were to add more slaves to the HSPI port?

[Bodmer]

The library uses hardware SPI.
It is not advisable to use the MISO pin as a control signal as it may cause problems with other libraries that use the same SPI bus.