STM8, SPI und SSD1306 - seltsames Verhalten

//Display constants

const unsigned char OLED_init[27]= {      // Initialization Sequence

0xAE,                          // Display OFF (sleep mode)

0x20, 0b00,                        // Set Memory Addressing Mode

                                            // 00=Horizontal; 01=Vertical;

                                            // 10=Page(RESET); 11=Invalid

0xC8,                          // Set COM Output Scan Direction

0x00,                                // --set low column address

0x10,                          // --set high column address

0x40,                          // --set start line address

0x81, 0x1F,                        // Set contrast control register

0xA1,                                // Set Segment Re-map. A0=0;A1 =127

0xA6,                                // Set display mode. A6=Normal; A7=Inverse

0xA8, 63,                        // Set multiplex ratio(1 to 64)

0xA4,                          // Output RAM to Display

                                            // 0xA4=Output follows RAM content; 0xA5,Output ignores RAM content

0xD3, 0x00,                        // Set display offset. 00 = no offset

0xD5,                          // --set display clock divide ratio/oscillator frequency

0xF0,                          // --set divide ratio

0xD9, 0x22,                        // Set pre-charge period

0xDA, 0x12,                        // Set com pins hardware configuration

0xDB, 0x20,                        // --set vcomh 0x20,0.77xVcc

0x8D, 0x14,                        // Set DC-DC enable

0xAF                                        // normal mode

};

void Init_display(void){

    PG_ODR = 0xFF;

    PG_DDR |= 0x03;     //PG0,1 ->outputs

    PG_CR1 |= 0x03;     //PG0,1 ->push-pull

    PG_ODR &= ~(0x01);  //PG0 set low, reset display

    Init_SPI();

    PG_ODR |= (0x01);   //PG0 set high

    display_send_command (OLED_init, 27);

    display_status |= (1<<7);   //set display status as "initialised"

}

if (ticks > 2000){

    if (!(display_status & (1<<7))){

        Init_display();

        //display_change_addressing_mode(0b01);

        //display_erase();

    }else{

        //display_set_cursor_x (127);

        //display_set_cursor_y (counter_pixelwrite);

        display_send_data (test, 8);

        counter_pixelwrite++;

    }

    ticks = 0;

}

0x20 0x01  //set vertical adressing mode

0x21  //Set Column Adress

0     //Column Start Address = 0

127   //Column End Address = 127

0x22  //Set Page Address

0     //Page Start Address = 0

3     //3 = 4 Pages (128x32), 7 = 8 Pages (128x64)