So I've been connecting 60% keyboards to various iPads for a few years now. Back in 2015/2016 doing so presented a few issues, starting with a nag dialog indicating that an unsupported device was detected. That went away with a subsequent iOS update, but my iPad would periodically reboot itself while it was idle instead. It was so regular that I suspected it was related to the iPad doing something during its FETCH cycle, but could never really prove it.
Well I now have a new 60% keyboard attached to my iPad Air 2018: an iGK61 and I have visual proof that the iPad is actively reaching out to the attached USB device (the keyboard) on a regular basis. The iGK61 has full RGB backlighting, which I have turned off during normal use, but whenever the iPad is awakened, the keyboard goes through an on/off pattern that rolls through every LED on the board. What's more interesting, however, is that I see a quicker version of this happen every 5 minutes while the iPad is idle.
My working theory is that previous keyboards (i.e., Vortex Pok3rs) never responded to this signal--whatever it is--from the iPad, except perhaps to be confused by it and not answer back in a way that the iPad likes, causing the iPad to reboot itself in the past. Whatever this iGK61 is doing when it receives this signal from the iPad--apart from the RGB light pattern--the iPad seems to be happier about it because it doesn't reboot itself.
What I really wonder is why the iPad is trying to perform this handshake with the attached USB device every 5 minutes.
