Can I use higher speed than 400kHz with I2C with STM32F439

Bus capacitance also limits I2C bus speed.

Check the STM32 reference manual for the chosen part. Some I2C can go over 400kHz, usually when all slaves are on the same board (no connector, no wires). The quality of the signal (speed, slewrate, capacitance/pull-up) must be tuned. Also remember ALL slaves should be compatible with higher speed. The highest speed is defined by the slowest slave's. Going beyond 400kHz requires sending a special command to slaves. Make sure they are designed for it.

However, before going to the brute force of speeding up, ask yourself if the communication done between MCU and slaves is optimal (are you using autoincrement multi-byte block transfer? some slaves have FIFO for bigger block transfer)....

Thanks for the remarks, and yes the remarks are all very very true. I think I have to rephrase my question:

The I2C spec has been upgraded over the years from 100kHz to 400kHz (fast mode) and nowadays you can go to speeds over 3MHz. What I specifically look for is the fast speed + mode, being 1MHz or above. Some controller may have this, some don't. I was wondering if the F4xx series do support the 'fast speed +' mode of 1MHz? Or when it is limited by design to 400kHz max, if there is a (pin) equivalent processor that does... Target processor used is the STM32F437VIT6 to be precise (not the 439 as I mentioned in the original question). 

Best regards,

Roland

Hi

van_straten.roland

I was wondering if the F4xx series do support the 'fast speed +' mode of 1MHz?

Yes there are some STM32F4 devices embedding I2C that support fast mode plus mode (called I2CFMP). You have to refer to new devices likes STM32F410, STM32F412, STM32F4..

-Amel