Startup I2C Clock Rate for EZ-USB® FX2LP™ - KBA85384

Version: **

 

Question: Can I change the clock rate of the I2C device to 100 kHz after startup? Must it be 400 kHz at startup to properly enumerate?

 

Answer:

The bus frequency defaults to approximately 100 kHz for compatibility, but you can configure it to run at 400 kHz for devices that support the higher speed. Setting bit 0 of I2CTL (E67A) register to 1 causes EZ-USB to drive SCL at approximately 400 kHz. When the CPU begins to run, firmware can modify the I2CTL.0 bit.