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On 08/07 11:29, Stefan Mark wrote: |
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> On Sun, 6 Aug 2017 19:04:09 -0500 |
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> R0b0t1 <r030t1@×××××.com> wrote: |
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> |
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> > On Sun, Aug 6, 2017 at 11:50 AM, <tuxic@××××××.de> wrote: |
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> > > When I plug in such a little board into my PC, demesg |
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> > > reports: |
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> > > [ 1429.834140] usb 7-4: new low-speed USB device number 15 using |
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> > > ohci-pci [ 1429.965142] usb 7-4: device descriptor read/64, error |
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> > > -62 [ 1430.203151] usb 7-4: device descriptor read/64, error -62 |
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> > > [ 1430.438161] usb 7-4: new low-speed USB device number 16 using |
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> > > ohci-pci [ 1430.569151] usb 7-4: device descriptor read/64, error |
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> > > -62 [ 1430.803174] usb 7-4: device descriptor read/64, error -62 |
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> > > [ 1431.038184] usb 7-4: new low-speed USB device number 17 using |
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> > > ohci-pci [ 1431.456157] usb 7-4: device not accepting address 17, |
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> > > error -62 [ 1431.582204] usb 7-4: new low-speed USB device number |
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> > > 18 using ohci-pci [ 1432.000209] usb 7-4: device not accepting |
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> > > address 18, error -62 [ 1432.000244] usb usb7-port4: unable to |
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> > > enumerate USB device |
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> > |
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> > > |
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> > > My first thought was: The micronucleus bootloaed is missing or |
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> > > is defective... |
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> > > |
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> > > But plugging in the board into my Android tablet (the tablet runs |
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> > > Lollipop and is nothing special at all beside being rooted) via |
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> > > an OTG cable and using lsusb after that, it shows |
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> > > Bus 001 Device 003 ID 16d0:0753 MCS Digistump DigiSpark |
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> > > |
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> > |
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> > What the dmesg output is saying is that your USB hardware has reported |
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> > a communication error to the driver. It is my guess that the ATtiny85 |
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> > is not meeting the timing requirements for USB. |
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> > |
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> > Looking at the board there does not seem to be a crystal oscillator |
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> > which most people would consider necessary for doing USB |
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> > communication. This is an oversight on DigiStump's part and it is very |
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> > likely you will not be able to fix the communication issues. You |
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> > should contact them and tell them that your computer will not |
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> > recognize their device and that you suspect it is because the clock is |
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> > too inaccurate. |
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> > |
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> > > |
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> > > What can I do to make this Digispark being correctly recognized? |
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> > > |
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> > > Thank you VERY much for any help in advance! |
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> > > |
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> > |
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> > Three things: |
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> > |
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> > 1) Return the one you bought and get a new one. The ATtiny85's |
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> > internal oscillator might be at the end of the bell curve but within |
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> > manufacturer tolerance, which isn't enough to produce a USB signal |
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> > close enough to the specified frequency. Expect the seller to pay for |
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> > return shipping. |
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> > |
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> > 2) You can calibrate the oscillator using instructions in this |
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> > application note: |
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> > http://www.atmel.com/Images/Atmel-2555-Internal-RC-Oscillator-Calibration-for-tinyAVR-and-megaAVR-Devices_ApplicationNote_AVR053.pdf. |
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> > This process still might not get you close enough. |
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> > |
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> > 3) Add a crystal oscillator to the ATtiny85 and change its fuses to |
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> > use the oscillator. You will need to recompile the firmware if the |
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> > crystal is a different frequency from the internal oscillator. |
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> > |
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> > It might work on your phone and not your desktop because of |
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> > differences in the USB hardware (your phone's serial decoder in the |
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> > USB hardware performs clock recovery but your PC does not) or because |
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> > there are multiple things on a USB hub in your PC and the ATtiny85 is |
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> > less accurate than those already present devices. Admittedly I'm |
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> > surprised it gets most of the way to registering as a device and then |
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> > fails, but I don't think the problem is with the drivers or your |
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> > kernel. |
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> USB uses a variant of non-return-to-zero for clock synchronisation, |
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> that should™ take care of timing issues. |
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> Actually, using microcontrollers without crystal for soft-usb is fairly |
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> common (i have a bunch myself). As far as i understand (but im no |
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> expert), trouble usually arises more from the improvised level shifters |
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> than timing issues. |
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> Anyway, i neither think there is a driver problem, i had a fair bit of |
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> the messages myself, usually fixed by fixing the level shifter. |
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|
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|
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Level shifters? What level shifters??? ;) |
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This board is THAT tiny...even the voltage regulator is bigger |
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than the MCU (http://digistump.com/products/1). |
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|
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I am not that confident into my soldering-fu to rearrange |
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anything on this board.... :) |