When is the AFIO clock required?

[nickkinchin]

Posted on May 30, 2009 at 09:54

When is the AFIO clock required?

[st3]

Posted on May 17, 2011 at 13:13

Yes, I think the STM32 documentation is particularly poor at giving this kind of information - See my post of 03-01-2009 at 12:56 in this thread:

http://www.st.com/mcu/forums-cat-7796-23.html

(should be bottom of the 1st page)

[nickkinchin]

Posted on May 17, 2011 at 13:13

Hi,

I can find no mention of when it would be required to enable the AFIO clock.

The firmware library examples sometimes enable but mostly don't. The documentation says nothing about it.

Could somebody clarify when it should be enabled please? Does anybody actually know?!

Thanks, Nick.

[16-32micros]

Posted on May 17, 2011 at 13:13

Dear gentlemen,

Please refer to our FAQ Knowledge base : we have added one regarding this Topic :

http://www.st.com/stonline/faq/faqview.php?ids=1222

Cheers,

STOne-32.

[christophe239955_st]

Posted on May 17, 2011 at 13:13

Hi,

Check Section 7.4 AFIO registers in the RM0008:

Note: To read/write the AFIO_EVCR,AFIO_MAPR and AFIO_EXTICRX registers, the AFIO clock should first be enabled.

Chris

[lil-vince]

Posted on May 17, 2011 at 13:13

Hi,

Quote:

The documentation says nothing about it.

I agree:

http://www.st.com/mcu/forums-cat-7813-23.html

[ This message was edited by: lil-vince on 30-05-2009 10:04 ]

[nickkinchin]

Posted on May 17, 2011 at 13:13

Thank you STOne-32,

I tried searching before I asked. Honestly.

Thanks again for your help.

Regards, Nick.

Ps, The EXTI worked for me when it was connected to PA0 (WITHOUT having the AFIO clock enabled).

Perhaps the AFIO clock is only required when the EXTI lines are connected to pins other than on Port A (default)? Cheers.