A very nice writeup and intro into USB, although - it's very focused on using an ST microcontroller, which is a lot more steps and toolchains compared the the recent ESP32 ecosystem that offers a number of easy plug-and-play ways to make USB devices work (for example, several projects from Adafruit's learning pages provide basic use cases). Another issue is differential pairs - having designed several working USB boards myself, this has not a concern for beginners, mainly relevant for doing high-speed work. USB controller ICs (as used typically with arduio/esp) can handle a lot of the details for you, so doing the calculations seems overkill, especially for someone making their first gadget.
I recently built a small hand-wired macro pad using an Arduino Pro Micro equipped with ATmega32U4, it's apparently quite popular amongst hobbyists building custom keyboards. Quick and fun project for a beginner, the most tedious part of this project was to carve the wooden case.
Do you have a link to a PCB/kit, preferably with LEDs? Does yours run QMK? It sounds like a nice project if it costs a few bucks to get the materials, though I don't know what I'd do with it.
I didn't used a kit, but bought the components separately (microcontroller, key caps, switches, wires). It runs custom code as it was sufficient to fit my use case, though QMK may be possible? The keys are mapped from F13 to F22 and can be use in some software that allow custom keybinds.
This is great, thanks! I had researched extra F keys when I was making my keyboard (exactly to use as macros) but I hadn't discovered F13 to F22, thank you! That's exactly what I needed.
I think it is nice to have a basic understanding of differential pairs and impedance, I will admit I never really had to do the calculations since the ecad software I use has several tools for routing differential pairs and even analyzing signals for impedance. But as long as you keep your traces really short it normally doesn't matter.
I just looked up the USB2514, and it would seem to not support PerPortPowerSwitching. (used by e.g. uhubctrl to toggle/switch power to individual USB ports). Am I not reading the specs correctly?
I was able to reset downstream USB devices using usbreset to the individual ports (or the entire hub) in my design, using usbreset. I did also have a hardware reset built in using the cfg_sel0 and cfg_sel1 pins 24 & 25 and RESET_N. I did not try to turn off power to those ports for any extended time so I am not sure if that works.
