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Hi, |
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On 08/06 07:04, R0b0t1 wrote: |
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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 ohci-pci |
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> > [ 1429.965142] usb 7-4: device descriptor read/64, error -62 |
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> > [ 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 ohci-pci |
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> > [ 1430.569151] usb 7-4: device descriptor read/64, error -62 |
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> > [ 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 ohci-pci |
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> > [ 1431.456157] usb 7-4: device not accepting address 17, error -62 |
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> > [ 1431.582204] usb 7-4: new low-speed USB device number 18 using ohci-pci |
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> > [ 1432.000209] usb 7-4: device not accepting address 18, error -62 |
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> > [ 1432.000244] usb usb7-port4: unable to enumerate USB device |
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> > |
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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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The above is the only part of the dmesg log regarding this usb |
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"device"... |
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|
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If I plug it into a usb-port, it "works"... (read: will be recognized |
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according to dmesg, but still the udev rules dont get triggered, so |
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I still get nothing under /dev/... |
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|
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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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...the board is a thumbnail thing: |
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http://digistump.com/products/1 |
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|
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No crystal. It is not an original digistum and had cost me less than 1 |
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EUR...so not such a painful loss... |
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|
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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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Returning the board does cost more than the board and I haven't |
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any hope that this will change anything: I have six of them and none |
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works. "The design can be improved..." to be friendly. |
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|
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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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I have no oscilloscope nor a frequency counter. |
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That is above my financial possibilities... |
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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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There is not enough space on the board. |
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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. It's also not very likely to be a problem with the USB code |
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> unless it was reimplemented for DigiStump's product (check against |
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> these libraries |
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> http://www.fourwalledcubicle.com/files/LUFA/Doc/120219/html/_page__alternative_stacks.html). |
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> |
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> R0b0t1. |
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> |