Communication Adapter

Connecting things to a Windows PC is sometimes a bit of a challenge. I am in urgent need of a CAN-X adapter. These things cost and if I add my request for a Wired Ethernet, Wireless Ethernet as well as USB prices start to have several digits. The amount of software needed and the component cost is however not that big a job, so I can as well make one myself for the fun of it.

Communication Adapter2

I will use STM32F405RG as MCU this time. This is an overkill, but I fancy doing something with this small M4 and it only cost 5.- USD.

  • – 32bit ARM M4 168Mhz, 1Mb Flash, 192+4Kb SRAM
  • – BasicPI SWD connector
  • – Issolated RS485
  • – Issolated CAN HS
  • – NRF24L01+
  • – 10/100Mbps Ethernet
  • – Wifi
  • – USB

This is my first Ethernet design and I am cheating big time. The F405 don’t have a Ethernet connector so I am adding a Wiznet W5500 chip. This provide a hardwired TCP/IP stack that we interface to through SPI. The smaller version of this W5100 should be well known for hobby makers.

As for Wireless we use ESP8266. Either ESP-3, ESP-12 or similar. This is a cheap solution that will work well in this case.

I am doing the same trick on USB. This MCU actually have a USB connection, but I am cheating and using a CH340 to get a serial over USB connection. I have used this for years and I never have any fuzz with this one. Programming a serial port is also much easier than programming USB drivers.

The rest of the code is a small router. I will not be doing any clever code on the CAN. I simply want to provide a dumb remote I/O and let software on the PC do the rest.

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