GPIOS Input mode pins affecting output mode pins.

[Vikas Bhardwaj]

Posted on February 17, 2017 at 10:33

I am using STM32F4 micro controller and few GPIO pins i am making as input pins for sensor input staus and few as output pins to activate the LEDs. As soon as i configure few pins as input pins for sensor, few out pins for LED drive stop working, I am confuse, what could be the reason, software or hardware?

[Oliver Beirne]

Posted on February 17, 2017 at 12:49

Hello

I have moved your question to the

https://community.st.com/community/stm32-community/stm32-forum?sr=search&searchId=6c49c51e-345f-465b-bac5-e5d475b0e81b&searchIndex=0

‌ where someone should be able to assist you.

Thanks

Oli

[Vikas Bhardwaj]

Posted on February 17, 2017 at 13:02

Thanks!!

[S.Ma]

Posted on February 18, 2017 at 16:29

Use BSSR register from Gpio to modify digital outputs, not DR directly. Make sure MODER register is written properly too. If using a debugger, stop the code in your main loop, open the register window and view the gpio register. Manually play with them to check it out.

[Vikas Bhardwaj · Accepted solution]

Posted on February 20, 2017 at 06:26

Thanks for your suggestion.

Problem has been resolved, It was because of optimization settings of the tool. I disabled option for  'common sub expression delete' then firmware start working properly, So seems like my code optimized by the tool and getting this issue . 

Could some body tell me coding rules or standard(MISRA C), so that I could avoid this problem?