I am trying to connect 3 SPI devices to my pi 5, they are all RFID-RC522 modules and so they all have the same device id, so I put them on separate busses.
I researched and selected these three overlays for the /boot/firmware/overlays/config.txt file:
overlay= pins cs pin
spi2-1cs-pi5 1-3 0
spi3-1cs-pi5 5-7 4
spi5-1cs-pi5 13-15 12
I now have these /dev entries:
spidev10.0
spidev2.0
spidev3.0
spidev5.0
I don't know what spidev10.0 is, it was there before.
The pin numbers above came from the /boot/firmware/overlays/README file where I selected my overlays to activate, but I don't quite get what I'm doing here, re:
- I've never used a chip select pin before today, do I need to connect it?
- It's great to say pins 1-3 and 0 but which pins connect which way
- The pinouts I can find for Pi 5 don't line up with the numbers from the overlay file, don't have a pin 0 and some of the pins specified are for power
- Information specific to the Pi 5 is difficult to get online.
- The modules have these pins: sda, sdk, mosi, miso, irq, gnd, reset, 3.3v
I'm guessing I can leave IRQ and reset tied low, but that still leaves me sda, sdk, mosi, miso and NO cs pin on the module, what connections should I make for these three overlays?
