Kriege den SPI Bus nicht zum laufen

// Pins SCLK and MOSI are fixed in hardware, and pin 10 (or 53) 
// must be an output
//#define sclk 13    // for MEGAs use pin 52
//#define mosi 11    // for MEGAs use pin 51
#define cs 10   // for MEGAs you probably want this to be pin 53
#define dc 9
#define rst 8  // you can also connect this to the Arduino reset

// Color definitions
#define	BLACK           0x0000
#define	BLUE            0x001F
#define	RED             0xF800
#define	GREEN           0x07E0
#define      CYAN            0x07FF
#define      MAGENTA         0xF81F
#define      YELLOW          0xFFE0  
#define      WHITE           0xFFFF

#include <ST7735.h>
#include <SPI.h>

// Option 1: use any pins but a little slower
//ST7735 tft = ST7735(cs, dc, mosi, sclk, rst);  

// Option 2: must use the hardware SPI pins 
// (for UNO thats sclk = 13 and sid = 11) and pin 10 must be 
// an output. This is much faster - also required if you want
// to use the microSD card (see the image drawing example)
ST7735 tft = ST7735(cs, dc, rst);

Also im oberen Code die Pin 10 durch Pin 53 ersetzen?
Tut mir leid für diese simplen Fragen, Stecke nicht so in dem Thema drinn und bin blutiger Anfänger...