Replacing A4988 Drivers with DRV8825 on Arduino Mega 2560 + Ramps

[Mjolinor]

Using Octoprint from Raspberry Pi or connected directly to my computer using USB will give me a communication error after a short time & the printer stops. Printing directly from the SD card does not cause my printer to stop. Unless there is a problem on the USB connection on my computer & raspberry the problem looks like it points to somewhere in the USB circuitry of the arduino. Is that logic not correct? I have also tried 2 different USB ports on my computer with the same problem. Is there some Ethernet shield that I could attach to the arduino mega instead of using the USB connection?

No that is not correct. Read what I have written. USB specification does not support real time protocol.

USB SPECIFICATION DOES NOT SUPPORT REAL TIME PROTOCOL.

Any clearer?

Three times I said it now, this is the last time.

[PyramidDave]

What I do not understand is how I have been using it successfully for 1.5 years without this problem & all of a sudden I have a problem. If the fact that USB does not support real time protocol played into this problem, wouldn't I have had a problem a long time ago? I have 2 to 3 thousand hours of printing on this printer.

What electronics are you using on your printer and how do you connect to it?