Getting corrupted data when reading DS18B20's ROM code.

[D@rkD@iver]

Hi, I'm trying to read ROM code from DS18B20 using AtTiny2313.
DS18B20 gives presense signal as it supposed to. Then I sent 0x33 command and read 8 bytes.
I read 8 non-0xFF bytes. but they are not representing the ROM code (LS byte isn't 0x28).
I tested it in proteus and in real device. the result is similar - just 8 numbers (diffrent for device and proteus). But those numbers repeat after I restart the system.

if (DS_isPresent())
	{
		LCD_Clear_Display();
		DS_Send_Byte(0x33);

		for (int i=0; i<8; i++)
		{
			byte b = DS_Read_Byte();
			LCD_Show_Byte(b);
		}
		return 0;
	}

DS_Send_Byte function should be right, DS18B20 recognizes it. I think so because I read exactly 8 numbers(ninth byte is 0xFF) and if I change 0x33 to other command it receives all 0xFFs.
I'm concerned with DS_Read_Byte function.

byte DS_Read_Bit()
{
	byte r = 0;
		DSDDR |= 1<<DSBIT;
		DSPORT &= ~(1<<DSBIT);
		_delay_us(15);
		DSDDR &= ~(1<<DSBIT);
		_delay_us(15);
		if (DSPIN&(1<<DSBIT))
		{
			r = 1;
		}
		_delay_us(30);
		return r;
}

byte DS_Read_Byte()
{
	byte b = 0;
	for (int i=0; i<8; i++)
	{
		b = b << 1;
		b = b + DS_Read_Bit();
	}
	return b;
}

this is what I get in proteus

LCD is fine I double checked it.
By the way the code of DS18B20 in proteus is B8C530
So what might be the problem?
Thank you.