I2c port 3 in Colibri T20 not working

i am trying to interface the colibri T20 I2c Port 3 with an Atmel microcontroller. I have checked on the I2ClibDemo from your website and whenever i run the i2cscan() method i get only the RTC listed on the available buses with the address of 0x68. I am configuring my I2C Data and I2C Clock pins on the CAM_I2C_SDA(X1 pin number 127) and CAM_I2C_SCL(X1 pin number 133) respectively on the Colibri T20 module. I tried disabling the RTC using the article RTCSync . But i couldnt find any registry assigned under that key. I have tried even a sample code available in this link How to use ADC PWM I2C library in VCSharp | Toradex Developer Center. Can you suggest me a suitable method to implement the same?

To disable the RTC on our carrier boards, you need to rename the following key:


Just add any character in front of “rtcsync.exe” or order to prevent the RTC protocol from being loaded. On newer Evaluation Boards there is also a jumper to disconnect the external RTC (Jumper “INT RTC”).

One other thing could also be, that your I2C chip communicates with an other speed. See API function I2CSetSpeed (I2C Lib API | Toradex Developer Center ).

If you see the RTC chip in the code, it may could be a hardware issue. Is there anything that blocks your chip from running properly? Could you measure the signals?