I2C speed mode is defined only by timing?

[Pavel A.]

When I2C "Speed mode" changes in CubeMX/IDE from Standard to Fast, it seems that only the Init.Timing value changes in generated code.

This value goes into TIMINGR register of the I2C .

Am I missing anything or this value defines the "speed mode" entirely?

That's, the "speed mode" exists only in the Cube's GUI?

The chip is STM32H743/753

Thanks,

Pavel A

[waclawek.jan]

> Am I missing anything or this value defines the "speed mode" entirely?

I2C Fast -mode is defined in chapter 5.1 of the I2C specification.

JW

[Pavel A.]

Yes, in the RM there are no other register bits related to the "speed mode", only the TIMINGR value.

-- pa

[Piranha · Accepted solution]

In addition the SYSCFG_PMCR register has I2CxFMP and PBxFMP bits for Fast-mode plus (Fm+).