AN4488, Chapter 3.2.2, Pin 30

[KLausL]

Posted on February 24, 2016 at 09:49

Hello Forum,

regarding the AN4488, Chapter 3.2.2 I do not understand why the capacitor at pin 30 is necessary. The STM32F4 as well as the STM32F1 have a ''normal'' gpio there.

Thanks in advance!

Klaus

#hardware

[Nesrine M_O]

Posted on February 24, 2016 at 14:55

Hi Klaus,

The Pin 30 in LQFP64 package is a GPIO for STM32F1 family but it is a VCAP pin for STM32F4 family for this reason an external ceramic capacitor should be connected on it. 

Check for example the STM32F401 datasheet.

-Syrine-

[KLausL]

Posted on February 25, 2016 at 16:20

I use the STM32F405RG and there the Pin 30 is just a normal GPIO (cf.  http://www.st.com/web/en/resource/technical/document/datasheet/DM00037051.pdf, page 51)

Best regards

Klaus