void lcd_blit_grey_phase(unsigned char *values, unsigned char *phases,
                         int x, int by, int width, int bheight, int stride)
{
    if (lcd_initialized)
    {
        stride <<= 3; /* 8 pixels per block */
        while (bheight--)
        {
            lcd_write_command(LCD_SET_PAGE | (by & 0xf));
            lcd_write_command_e(LCD_SET_COLUMN | ((x >> 4) & 0xf), x & 0xf);

            lcd_grey_data(values, phases, width);
            values += stride;
            phases += stride;
            by++;
        }
    }
}