[ATmega32][C] Problem with communication with sensor SFH5712 by I2C

[damiandoles]

Hello everybody I am working on engineering work and now I have big problem...I can't do nothing more without it. I'd like to connect with light ambient sensor OSRAM SFH5712, which communicate with ATmega32 by I2C bus, but there is low voltage - only 1,8V and 3,4 Mbit/s communication speed. Of course, this sensor can work with lowest frequency - 100kbit/s, 400kbit/s so I understand that it could be possible to connect with ATmega32 - for example with frequency 400kbit/s. In this case I understand that pull-ups resistor must be changed (560Ω for speed 3,4Mbit communication), but what resistor should be there for lowest frequency ? Next problem is low voltage, as I said. ATmega don't understand 1,8V - high level is when the voltage will be more that 2,5V, so I need logic converter - for example using transistors. I have attached some scheme, but It didn't work. Processor couldn't connect with sensor. Everythink what I did, it was made with datasheet (for software). Big problem is that, I bought 3 sensors, but now...I have the last one :-? I have destroyed two when I wanted unsolder it. This sensors are very small...about 2x2 milimiters. It is my last sensor and If I destroy it, I can't buy next because in my country I couldn't find shop with this sensor...I brought it from Germany. The library of TWI is working. I am really worried about it, what can I do with it :-? I hope that somebody will help me, I really thank you in advance for your help.

---

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>
#include "TWI.h"
#include "HD44780.h"
 
int main(void)
{
    LCD_Initialize();
    LCD_Clear();
    TWI_Init();
 
    unsigned char B, C;
    char tab1[8];
    char tab2[8];
    
    while(1)
    {
 
        //_delay_ms(5);
        TWI_Start();     
        TWI_Write(0x29); 
        TWI_Write(0x80);
        TWI_Write(0x03);
        //_delay_ms(300);
                            
        TWI_Start(); //repeated start
        //TWI_Write(0x29); 
        TWI_Write(0x8C);
        
        TWI_Start(); //repeated start
        B = TWI_Read(NACK);
        
        TWI_Start(); //repeated start
       // TWI_Write(0x29);
        TWI_Write(0x8D);
        
        TWI_Start(); //repeated start
        C = TWI_Read(NACK);
        
        TWI_Start(); //repeated start
        //TWI_Write(0x29);
        TWI_Write(0x80);
        TWI_Write(0x00);
        TWI_Stop();       
        //Hex(B,tab1);
        //Hex(C,tab2);
        
        //LCD_GoTo(1,0);
        //LCD_WriteText(tab2);
    }
}

---