Broke my TinyGv8

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  • September 9, 2014 at 2:37 pm #6737
    flux
    Member

    Hello,

    It appears I’ve finally succeeded in breaking my board. Well, it was fun 11 months.

    I was trying to mill a piece and my settings were perhaps not quite correct, the spindle was having hard time and the spindle auto restarting mechanism of the VFD kicked in. Very shortly after that I pressed the reset button. After this point I was no longer able to access the device over USB. Not only that, but also the USB hub that was connecting the device to PC is no longer able to enumerate devices attached to it, though the hub itself is visible to the PC (I replaced the hub with an identical and that hub works fine). So there has probably been some electrical event here..

    I don’t quite know what happened here. Options could be:
    – The VFD did something strange and a strong pulse was sent over the wall socket – not very likely as the PC had no issues
    – The VFD did something strange and a strong pulse was sent over the VFD adapter I have – but it seems curious if it would be able to drive the signal through the ULN2803 to the board.
    – While pressing the reset button I passed a big ESD pulse to the pin next to the reset button.
    – Something else?

    I also tried to connect the board directly to the PC, linux’s conclusion is “hub 6-0:1.0: unable to enumerate USB device on port 5”.

    It appears it does the normal startup sequence judging from the leds, as far I can see.

    What would be the suggested course of action? I have some debugging facilities (multimeter, oscilloscope, low bandwidth logic analyzer, 3.3v USB serial adapter). Or should I ship the device back to Synthetos, or just give up and buy a new one?

    September 9, 2014 at 4:03 pm #6741
    cmcgrath5035
    Moderator

    My condolences.
    Sounds like a bad voltage somehow got onto the USB interfaces.
    Any particular reason you had a (sacrificial) USB hub between the PC and the TinyG. Sounds like maybe that is a good idea, just in case……

    September 10, 2014 at 12:37 am #6745
    flux
    Member

    Practical reasons. I have quite a few USB devices and the USB port of the PC is difficult to reach, so I’ve brought the USB ports reachable with a few USB hubs.

    Yes, I too am happy for having the hub there ;).

    September 10, 2014 at 2:03 pm #6750
    flux
    Member

    Well, I ordered a few FT230XS chips from Mouser, so I shall see if it works after replacement after a week or so.

    September 10, 2014 at 3:15 pm #6751
    cmcgrath5035
    Moderator

    Do you have a V7 or V8?
    If V7, Note the 5v regulator (U2) that seems only used by the ftdi device and as an output source/reference. 5V still good on your board?

    September 10, 2014 at 3:28 pm #6752
    flux
    Member

    It’s v8.

    Yeah, perhaps I should have done some measurements first (and still could do..) on the voltage levels around the FTDI chip just to be sure FTDI has power, though how would I know if it’s not pulling a line down when broken without removing it, which I of course need to do at some point.

    In the v8 there is also this two-line EDS protection diode PESDxL2BT which could be broken, but surely it wouldn’t break in a way that makes it short the GND with USB signal lines? And if it’s defunct now, it ‘only’ removes the ESD protection.. But now I will have plenty of spare FTDIs, no sense ordering only one at those shipping costs ;).

    I should also hook up the TTL serial up to see if I can communicate over that. Probably not the final solution even if it works.

    Thanks for pointing that out even if it didn’t match ;).

    November 10, 2014 at 3:12 pm #6980
    flux
    Member

    So, I finally did the effort of replacing the FTDI chip.

    And, lo behold, it works! Well, at least it interacts with the replacement USB hub and the computer, I didn’t hook it up to the motors yet. The quality of my soldering.. Well only time will tell :).

    An additional bonus I got from the new FTDI chips, was new speeds: I didn’t recall being able to go to 460800 and 921600 bps before switching the chip, probably a new revision of it even if it is the same type. It’s probably easy to add support to those speeds to TinyG, but I wonder, is it worth it? Will TinyG be able to process that speed? At least it would be faster to send responses to the host machine.

    In any case, I’m happy that I’ll be able to check out what is cooking with the software, resume doing PCBs and try breaking the board again :).

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