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??? ;) This board is THAT tiny...even the voltage regulator is bigger than the MCU (http://digistump.com/products/1). I am not that confident into my soldering-fu to rearrange anything on this board.... :)
