Smartmatrix + teensy + rc522 rfid

I use my teensy + smartmatrix for displaying gifs in a musical project, along with a score

I would like to add a funny feature by introducing a rfid reader (rc522). It uses SPI but the rfid reader integration seems to add some strange colours on the display.

Do I need to use specific pins for this ? Is smartmatrix also sharing SPI pins ? ( rfid is using mosi miso sck sda pins from teensy 4.1)

Thanks a lot for your help

The SPI pins (11-13) are used by the Smartmatrix 4.x shield. On the Teensy 4.1 you can use the second SPI bus (pins 0, 1, 23). However, your RFID driver has to have an option to use the 2nd SPI bus instead of the first.

I believe that the Smartmatrix board uses pins 2, 3, 6 and 8-13 for the matrix display and pins 4, 5, and 22 for the APA102/dotstar LED string.

Hi Michael!
Thanks a lot for the help ! I found this example using rc522 on SPI1… I will try it soon, I’m pretty confident it should work :wink:

Will keep you posted !

From what I’ve seen on teensy 4.1
Miso1 pin 1
Mosi1 pin 26
Sck1 pin 27
Cs1 pin 0