Unable to communicate with SC16IS750 over I2C

Showing results for 
Search instead for 
Did you mean: 

Unable to communicate with SC16IS750 over I2C

Contributor I


Im unable to read any register via I2C. Also i noticed that I dont get any clock signal, but rather 1.5v constant voltage on XTAL pins. Does it mean that the chip doesnt startup?



Tags (1)
0 Kudos
1 Reply

NXP Employee
NXP Employee

Herllo Sergey,

Thank you for writing.


First of all, please confirm that you have the correct connection.


You may use the OM6270 Demo Board as a reference for your design. Please find the schematic attached to this response.


Before any data is transmitted or received, the master must send the address of the receiver via the SDA line. The first byte after the START condition carries the address of the slave device and the read/write bit. Table 32 from the datasheet shows how the SC16IS740/750/760’s address can be selected by using A1 and A0 pins. For example, if these 2 pins are connected to VDD, then the SC16IS740/750/760’s address is set to 0x90, and the master communicates with it through this address.


Please review the A1 and A0 pins in your connection and please verify if you are sending the correct address based on the table mentioned above.



Please let me know if this information helps.


Best Regards,