On Mon, 7 Aug 2017 17:44:31 +0200 tu...@posteo.de wrote: > On 08/07 11:29, Stefan Mark wrote: > > On Sun, 6 Aug 2017 19:04:09 -0500 > > R0b0t1 <r03...@gmail.com> wrote: > > > > > On Sun, Aug 6, 2017 at 11:50 AM, <tu...@posteo.de> wrote: > > > > When I plug in such a little board into my PC, demesg > > > > reports: > > > > [ 1429.834140] usb 7-4: new low-speed USB device number 15 using > > > > ohci-pci [ 1429.965142] usb 7-4: device descriptor read/64, > > > > error -62 [ 1430.203151] usb 7-4: device descriptor read/64, > > > > error -62 [ 1430.438161] usb 7-4: new low-speed USB device > > > > number 16 using ohci-pci [ 1430.569151] usb 7-4: device > > > > descriptor read/64, error -62 [ 1430.803174] usb 7-4: device > > > > descriptor read/64, error -62 [ 1431.038184] usb 7-4: new > > > > low-speed USB device number 17 using ohci-pci [ 1431.456157] > > > > usb 7-4: device not accepting address 17, error -62 > > > > [ 1431.582204] usb 7-4: new low-speed USB device number 18 > > > > using ohci-pci [ 1432.000209] usb 7-4: device not accepting > > > > address 18, error -62 [ 1432.000244] usb usb7-port4: unable to > > > > enumerate USB device > > > > > > > > > > > My first thought was: The micronucleus bootloaed is missing or > > > > is defective... > > > > > > > > But plugging in the board into my Android tablet (the tablet > > > > runs Lollipop and is nothing special at all beside being > > > > rooted) via an OTG cable and using lsusb after that, it shows > > > > Bus 001 Device 003 ID 16d0:0753 MCS Digistump DigiSpark > > > > > > > > > > What the dmesg output is saying is that your USB hardware has > > > reported a communication error to the driver. It is my guess that > > > the ATtiny85 is not meeting the timing requirements for USB. > > > > > > Looking at the board there does not seem to be a crystal > > > oscillator which most people would consider necessary for doing > > > USB communication. This is an oversight on DigiStump's part and > > > it is very likely you will not be able to fix the communication > > > issues. You should contact them and tell them that your computer > > > will not recognize their device and that you suspect it is > > > because the clock is too inaccurate. > > > > > > > > > > > What can I do to make this Digispark being correctly recognized? > > > > > > > > Thank you VERY much for any help in advance! > > > > > > > > > > Three things: > > > > > > 1) Return the one you bought and get a new one. The ATtiny85's > > > internal oscillator might be at the end of the bell curve but > > > within manufacturer tolerance, which isn't enough to produce a > > > USB signal close enough to the specified frequency. Expect the > > > seller to pay for return shipping. > > > > > > 2) You can calibrate the oscillator using instructions in this > > > application note: > > > http://www.atmel.com/Images/Atmel-2555-Internal-RC-Oscillator-Calibration-for-tinyAVR-and-megaAVR-Devices_ApplicationNote_AVR053.pdf. > > > This process still might not get you close enough. > > > > > > 3) Add a crystal oscillator to the ATtiny85 and change its fuses > > > to use the oscillator. You will need to recompile the firmware if > > > the crystal is a different frequency from the internal oscillator. > > > > > > It might work on your phone and not your desktop because of > > > differences in the USB hardware (your phone's serial decoder in > > > the USB hardware performs clock recovery but your PC does not) or > > > because there are multiple things on a USB hub in your PC and the > > > ATtiny85 is less accurate than those already present devices. > > > Admittedly I'm surprised it gets most of the way to registering > > > as a device and then fails, but I don't think the problem is with > > > the drivers or your kernel. > > USB uses a variant of non-return-to-zero for clock synchronisation, > > that should™ take care of timing issues. > > Actually, using microcontrollers without crystal for soft-usb is > > fairly common (i have a bunch myself). As far as i understand (but > > im no expert), trouble usually arises more from the improvised > > level shifters than timing issues. > > Anyway, i neither think there is a driver problem, i had a fair bit > > of the messages myself, usually fixed by fixing the level shifter. > > > Level shifters? What level shifters??? ;) Oh, i see. Then i have to correct me, it seems that your board runs on 3v3 anyway (Which means i did not know those, only ones that look much alike). A level shifter wont be necessary then.
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