[quote=276058:@Derk Jochems]Well for one, you might burn the Pi’s chips. Second the communication could give errors.
It’s better to have 3.3v - 3.3v or 5v - 5v both with common ground.[/quote]
Thanks, Derk. As Ive written, yours and Jean-Yves answer are conflicting. Thats the uncertainty that made me start this thread. Do you know for sure there is a risk or do you have any links to follow?
Currently, it doesnt bother me that much because I reverted to USB communication, but it would be great to have a reliable answer. Any hints appreciated!
Sidenote: Like I wrote before, I tried it with a level shifter too and had no change in behavior except that the display that got its background lighting enabled via this level shifter came to life later. I suspect the level shifter itself, one of its lines seems to be somewhat slow.
Thanks, Derk! As I wrote, I removed the interrupt Gpio connection which has fixed the timing problems.
One question: When you burned your Raspi, was it when you tried to talk back from the Arduino or did you use the pin connection to talk to the Arduino only?
I have an Arduino hat for Raspberry Pi here too which uses a direct pin connection. Only the pins are too short, so you cannot attach a breadboard connector. Makes me wonder if connecting both is really that dangerous.
Anyway: I was feeling uncertain about connecting both and I am glad the USB connection works.
I have the idea that pigpio could make using a WS2801 together with a Raspi possible. Currently I use FastLED on the Arduino which does a lot of color tricks that would take a lot of time to rebuild on a Raspi solution if it should work anyway. I have only run into an issue where the use of a palette returns wrong values which puzzles me at the moment.