Connect 2 Arduinos via USB Shield

Projects Networking, Protocols, and Devices
1

Gidday,

I am trying to connect two Arduino Mega via an USB shield (Keyes Funduino) - i.e. one Arduino with the shield and the other Arduino connected via it's USB port to the shield's USB port. I am using Oleg's library from circuitsathome.

My code was built on his FTDI sketch - but when I run it I am always getting the error 0xD (J-state instead of response) message. The USB task seems to be properly initialised and running.

I am at my wisdom's end - can anyone please point me into the right direction ? The second Arduino will eventually be replaced by a car ECU, so I believe FTDI is the right choice. All ideas appreciated

2

Still having the issue, I have checked the D+ and D- of the USB output with an oscilloscope but it looks like there is a permanent noise (or data transfer ?) going on.

Any ideas how I can test whether the shield works alright ? Any easy-to-check FTDI devices that come to your mind ?

3

Maybe you should skip the USB approach (USB probably requires extensive knowledge of USB protocol and hardware) and go with a more typical serial communication setup.