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1. #Norway teensy driver doesnt work software#
2. #Norway teensy driver doesnt work code#
3. #Norway teensy driver doesnt work Pc#
4. #Norway teensy driver doesnt work mac#

Turns out the 4th byte describes features like which LEDs, over-current protection and other features the hub has. While I now know these differences are meaningless, and really only the 3rd byte (the number of ports) matters, at the moment I found these it seemed like this just had to explain the problem. 2 port (not working)Ĥ port, no-name blue color, UH-BSC4-US (works) It’s documented on page 417-418 of the USB 2.0 PDF. Hubs also have a special descriptor for their capability. Maybe someday we’ll detect power issues, but for now it’s ignored.

#Norway teensy driver doesnt work code#

But I know nothing in code on Teensy (which I wrote) ever look at this byte. The 2 port hub say 01, meaning only 2 mA which can’t be right.

#Norway teensy driver doesnt work Pc#

This byte is just the hub telling the PC how much power is might draw. I can’t emphasize enough how this process involves looking stuff up in the USB 2.0 PDF, in this case page 266. Turns out they’re an exact binary match, except for the last byte in the configuration descriptor. Most hubs have only a single TT, but 2 of my test hubs are Multi-TT. I’ll talk more about the transaction translators soon. Turns out this little 2 port hub is a Multi-TT type. Configuration Descriptor:Ĭlass/Subclass/Protocol = 9(Hub) / 0 / 1(Single-TT)Ĭlass/Subclass/Protocol = 9(Hub) / 0 / 2(Multi-TT) Here is the configuration descriptor for this 2 port hub.

I spent a few hours adding this code to print descriptor info. I decided this was a good time to fix that (rather than just plug into a PC and run a program to view), optimistically hoping the info would show some stark difference between this bad hub and all the good ones. But it doesn’t print much about the USB descriptors.

In USBHost_t36.h on line 59 is an option to turn on lots of verbose debug printing. With the protocol analyzer not helping much, I decided to first focus on question #2. The timestamps show it’s happening about every 8 to 12 microseconds! What’s Different About This Hub? Whatever was going wrong with this hub was causing a SETUP token to be repeatedly tried.

#Norway teensy driver doesnt work software#

A Force quit is needed.įortunately having the software lock up means at least something can be seen on the screen, even if I could not scroll up to look at any other data.

#Norway teensy driver doesnt work mac#

It hangs with the infamous Mac beachball. Unfortunately Total Phase’s software does not handle this situation well. This case turned out to be one of those problematic situations. It has to send a copy everything on that right side port, which can be problematic during periods of sustained fast data flow. Inside it has a fairly small buffer memory. A Mac laptop is watching the USB communication, and a Linux desktop is running the Arduino IDE to upload code to Teensy.ĭespite the high price, it’s not made of magic. Usually quite a clutter of cables is involved, but this little hub plugs right into the side of the Beagle480. Here’s the test setup, with the Beagle480 inserted between the Teensy 3.6 and 2-port hub. But when you’re making an embedded USB host like Teensy 3.6’s 2nd USB port, this is the only way to actually see what’s really happening. If you’re just making a USB device that plugs into your PC, usually you can run software to capture the data from your PC’s driver. But it makes a copy of all communication happening in either direction and sends it to the port on the right (green arrow). To whatever you’re monitoring, it just looks like a longer cable. On the left side where I drew the 2 blue arrows, your USB communication passes through. I have this one, the Beagle480 from Total Phase. Usually the first step in debugging USB problems is to hook up the protocol analyzer. In the end, both turned out to involve very wrong assumptions that were ultimately a distraction from finding the real problem. I believe most people would start with these 2 questions. What are they doing that Teensy isn’t?Ģ: All other hubs work on Teensy, so what’s different about this particular hub? Most of my first troubleshooting instincts revolved around these 2 questions:ġ: This hub works on Linux, Mac & Windows. You can much of the process as it actually happened on the forum thread where this problem was reported. This article is being written from the perspective of hindsight. In this article I’ll show how a protocol analyzer is used, how my instincts turned out to be very wrong, and along the way dive into arcane USB details you probably won’t see explained anywhere else. This tale begins with a customer reporting this cute little 2 port USB hub wasn’t working with Teensy 3.6.