Question: Do you have to connect the external pull-up resistors for the I2C lines of a USB-Serial Bridge Controller device?
Yes, the SCLK and SDATA lines of the I2C interface of the USB-Serial Bridge Controller device are open drain pins. External pull-up resistors must be connected on these I2C lines. These pull-up resistors should be connected to the VDDD supply. Recommended values for the pull-up resistors are shown in Table 1.
Table 1. Recommended Values for the Pull-up Resistors
|I2C Operating Frequency||Resistor Value|
|100 kHz||4.7 KΩ|
|400 kHz||2.2 KΩ|