That tells us nothing!
You've been directed to the Posting Tips before:
https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/ta-p/575228
You need to give full details before anyone is going to be able to help you!
So, again:
- What, exactly, have you tried?
Show code (following the instructions above) & give full hardware details, tools used, etc. - What were you expecting to happen?
- What actually happened - give full details; not just, "it didn't work"
- What investigation/testing/debugging have you done to find out what's going wrong?
Some general debugging tips here:
https://community.st.com/t5/community-guidelines/how-to-write-your-question-to-maximize-your-chances-to-find-a/tac-p/706966/highlight/true#M49
