Seeduino XIAO and RFID-RC522

Hi everyone,

I have rfid sensors rc522 connected to several arduino models and all is working very well.
Now I am trying to use seeeduinbo XIAO with those sensors but I am getting so many errors in the software that i dont realy know what to do.

The main errors that I am getting are:
error: invalid conversion from ‘char*’ to ‘byte* {aka unsigned char*}’ [-fpermissive]
error: invalid conversion from ‘byte* {aka unsigned char*}’ to ‘char*’ [-fpermissive]

Once I have all this working fine in the other arduinos, is there any compilation flag that fix this or do I need to change the software?

Thanks in advance for any help.


Can you tell me about the Arduino Library software you use? Let’s check it for you.

Hi Baozhu,

I use the MFRC522 version 1.4.6.

I am using this library in arduino uno and nano. I would like to change those arduinos to XIAO and I am stucked with this problem.
Thank you very much for your concern.


@antoniojteixeira Which sketch did you test? I’ll give it a try.

Hi Baozhu,

You can download the sketch from the link:

Thank you

Hi @antoniojteixeira, I would try it as soon as possible.