W5500 + FLIR camera on one SPI bus

Hello community,

I am trying to make a Flir Lepton thermal camera work on an Arduino Due with the W5500 ethernet module. Both are connected to the same SPI bus, using different CS pins. Separately (1 Module connected to the SPI bus at a time), the modules work like a charm. As soon as I connect them both to the bus, the ethernet stops working. It shows me 0.0.0.0 as the server IP. The Flir still works though.

This is what I tested yet:

  1. both on SPI bus, webserver example code, CS for the Flir HIGH -> server shows 0.0.0.0
  2. Ethernet fully on SPI, Flir only the clock pin on SPI -> server shows 0.0.0.0
  3. changed ethernet spi mode to 3, changed the SPI maximal frequency from 8Mhz to 16 or 4 -> server shows 0.0.0.0

I ran out of ideas, maybe someone has an idea what the problem could be ?

Thanks a lot !

Sounds like a MISO problem. Check if the Flir correctly tri-states MISO if CS is pulled HIGH. If that works I guess your software doesn't set CS correctly. One option is to use a level converter with an OE pin (same voltage on both sides). This way you can isolate the Flir bus from the other components.

Please post links to the technical datasheet of your Flir camera as well as to the schematics of your Ethernet module.