7" tft Ra8875 with arduino Uno

I am using a mutitouch 7" tft lcd with the RA8875 chipset

I have a problem wit the communication. I took the Adafruit_GFX lib from gifhub and the RA8875 lib they developed and managed to compile correctly. I fell into an infinite loop tho. The buildtest sketz uses spi mode 0 and and clock divider at 128 (i think that spi mode is 3 cause of the figure 6-18 in page 65 of the datasheet(tho it did not worked also). Also the sketz tries to read a register 0x0h i think and and returns false (witch goes in the infinite loop) if the value is not 75? I am trying to find this register in the datasheet to check its normal value in order to find where is the problem. Why after initializetion function library changes the clockdivider?

The code from the lib i am talking about is this:

     boolean Adafruit_RA8875::begin(enum RA8875sizes s) {
      _size = s;

      if (_size == RA8875_480x272) {
        _width = 480;
        _height = 272;
      }
      if (_size == RA8875_800x480) {
        _width = 800;
        _height = 480;
      }

      pinMode(_cs, OUTPUT);
      digitalWrite(_cs, HIGH);
      pinMode(_rst, OUTPUT);
      digitalWrite(_rst, LOW);

      digitalWrite(_rst, LOW);
      delay(100);
      digitalWrite(_rst, HIGH);
      delay(100); SPI.begin();
      SPI.setClockDivider(SPI_CLOCK_DIV128);
      SPI.setDataMode(SPI_MODE0);
     
      if (readReg(0) != 0x75) {
        return false;
      }

      initialize();

      SPI.setClockDivider(SPI_CLOCK_DIV4);

      return true;

After setting the spi mode in the code i did a few changes to test spi connection

  uint8_t x=readReg(0);
  Serial.println(x);

  writeReg(0,0x20);
  Serial.println(readReg(0));
  Serial.println(readReg(0x01));
  Serial.println(readReg(0x02));

The result in the terminal was the same every register give result 255

RA8875 start 255 255 255 255 RA8875 Not Found!

the last line is cause of the return of False and then the program goes to an infinite loop. The 7" tft is this: http://www.buydisplay.com/default/7-inch-lcd-module-capacitive-touch-screen-panel-i2c-spi-serial

Any help to make it work?