STM32F207 IOs output voltage levels

[anis239955]

Posted on May 09, 2012 at 14:37

Hi all,

I need some information regarding the STM32F207 IOs output voltage levels... in fact according to the datasheet (Table 44) the VOH Min is:

- 2.4 V for CMOS ports

- VDD - 0,4 for TTL port.

However I know that all STM32 IOs are both TTL and CMOS compliant, so in the case when my VDD is 3.3V, what will be my VOH min: 2.4V or 2.9V???? 

Note also that the max values of VOH for both TTL and CMOS are not mentioned in the datasheet!!!

With Best Regards

#ios-output-voltage-levels

[alok472]

Posted on May 10, 2012 at 03:22

Max values for Voh inever given in any datasheet, since it will be Vdd itself.

Similarly min of Vol will be 0.

in my opinion, for your requirement, take the best case for the Voh. It shall be 2.4V !

[John F.]

Posted on May 10, 2012 at 09:48

Output voltage high principally depends on the current that the pin driver must source. If you are drawing only a small current such as a CMOS input would draw then you will probably see VOut of close to +3.3V.

The data sheet also describes some specific pins which can source only low current and warns that there are maximum currents that ports (groups of pins) can supply.