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On Sun, 6 Aug 2017 18:50:07 +0200 |
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tuxic@××××××.de wrote: |
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|
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> Hi, |
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> |
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> sorry, this will become a little longish... |
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> |
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> Background: To program an ATMEL ATtiny85 via USB |
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> without a dedicated USB chip there is a bootloader |
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> called "micornucleys", which bitbangs the USB protocoll. |
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> This mechanism is used in Digistupms Digispark ATTtiny |
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> developmnent board (http://digistump.com/products/1). |
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> |
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> So far so ....nice? |
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> |
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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 -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 |
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> ohci-pci [ 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 |
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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 18 |
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> using ohci-pci [ 1432.000209] usb 7-4: device not accepting address |
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> 18, error -62 [ 1432.000244] usb usb7-port4: unable to enumerate USB |
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> device |
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> |
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> or similiar. lsusb does not show anything related at all. |
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> |
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That usually happens when the improvised USB is not good enough. Try a |
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different port, maybe put a USB Hub between. Check if the resistors and |
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diodes for the level shifting are the right ones (measure the |
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resistors, especially if you are not using 5% types). If that does not |
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work, try a different diode/resistor combination (For example, usbasp |
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uses 5v6 zener and 68/2k2 resistor, littlewire 3v6 zener and 27/1k2 |
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resistor. I have seen others too. I had at least one which never |
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worked with my laptop). |
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|
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> As recommended on related pages on the internet, I installed |
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> dedicated udev rules to show the needed ttyACM device. But |
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> since the kernel itsself fails to accept the device, the best |
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> udev rules will not work. |
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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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Some ports are more forgiving than others. These soft-usb-thingies tend |
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to be a bit rough, especially the level conversion seems to be a bit |
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icky :) |
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I have a usbasp which works always and everywhere i tested it just |
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perfectly. One of my littlewires is a bit wonky (it sometimes looses |
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connection and needs a few tries until it works again). Another one |
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works fine, but not on every device. |
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