 
 #define DEBUG
 
+void uart_send_byte(uint8_t c);
+
 extern uint16_t ssd1306_color;
+
+///////////////////////////////// VGA INTERFACE ///////////////////////////////////
+
 static uint8_t s_vga_command = 0xFF;
 static uint8_t s_cursor_x = 0;
 static uint8_t s_cursor_y = 0;
 static uint8_t s_column = 0;
 static uint8_t s_column_end = 0;
 static uint8_t s_page = 0;
+
 static uint8_t s_vga_buffer[64*40/2] = {0};
 
 void vga_interface_init()

    s_vga_buffer[addr] |= color;
}

void vga_interface_send_byte(uint8_t data)
{
    if (s_vga_command == 0xFF)
    {


void vga_interface_stop()
{
    s_vga_command = 0xFF;
}

void vga_interface_close()
{
}

void vga_put_pixel4(uint8_t x, uint8_t y, uint8_t color)
{
    uint8_t mask;
    if (x&1)
