Hello, I'm working on a school project and I've ran into some problems. Long story short I'm using GT 511c3 Fingerprint Scanner wired to FRDM-KL25Z. I'm using UART2 pins, PTE22 and PTE23. https://www.sparkfun.com/products/11792 I've found a library for a mentioned scanner, but unfortunately It's not very readable to me. https://os.mbed.com/components/GT-511C3-GT-511C31/ I'm currently at stage where we've just started learning writing our own libraries. So we could say that this is my first interaction with a library. I've imported test program on FRDM and the problem is I can't get any response from scanner!? Small green led and blue led on fingerprint are turned on! No matter what I do I can't go past 1st enroll:

Could someone please take a look at this, and If nothing give me some opinions and ideas on what to try next to get this working.

Hi Simon,

I'd recommend moving your project to Mbed-CLI and get the debugger working. Here are links which you may find useful:

https://github.com/ARMmbed/mbed-cli https://docs.mbed.com/docs/mbed-os-handbook/en/5.4/debugging/vscode/

Remember to keep your tools up-to-date.

Hth

Neil

That library indeed seems to lack some kinda of comments / documentation. In general I would advice you to add printfs to see where it is going wrong. Debugging tools can be powerfull, but things like that in my experience work fine to debug with printf. I have debugged serial drivers with serial printfs, but I wouldn't advice that :P.

But things like this which are low speed and you don't need to add breakpoints or things like that, printf style debugging brings you quite far in my experience.