USB workaround

Hardware related problems and workarounds

Re: USB workaround

Postby ajtravis » Sun Jul 17, 2016 10:15 am

Frida wrote:Congratulations 2 year and 1 day, and still no solution in sight.


Hi, Frida.

Well, I've bought more Parallela's and some Porcupine boards because Parallella is still a very interesting platform despite the USB issues!

Personally, I just use the serial port and NFS now - I've stopped investigating the USB problem because it's futile asking Adapteva to do anything about it.

I think the Parallella lost credibility as a more powerful alternative to the Raspberry Pi partly because of the USB problem but more likely because of Adapteva's denial that there is a USB problem at all: That's a bit NEGATIVE for many of us, of course, but not enough for me to abandon my interest in the Parallella :-)

The USB issue will ONLY be diagnosed by someone in the Parallella community because Adapteva don't regard it as a 'real' issue. Complaining about it will not solve the problem. As I've said many times before on this forum, Adapteva did WELL to bring Parallella to us at an affordable price. The USB issue is disappointing, but it is NOT a show stopper and you CAN use the serial port to control the Parallella directly, as I do. HOWEVER, I think it is RIDICULOUS that Adapteva deny there is a USB problem!

Bye,

Tony.
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my ssh is not working

Postby anuginureni » Wed Oct 24, 2018 9:00 am

My ssh into parallella board was not working. so i did a reset of the board and now both ping which was working earlier is also not working
Please help
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Re: my ssh is not working

Postby ajtravis » Wed Oct 24, 2018 9:10 am

anuginureni wrote:My ssh into parallella board was not working. so i did a reset of the board and now both ping which was working earlier is also not working
Please help


Hi, anuginureni.

Connect a TTL-USB serial cable to the UART using the three pins next to the Ethernet connector:

https://www.amazon.co.uk/USB-TTL-Serial-Cable-Raspberry/dp/B00DJUHGHI/ref=sr_1_6?ie=UTF8&qid=1540371995&sr=8-6&keywords=usb+ttl+cable

You can use the Parallella serial console to debug problems with your Ethernet connection.

HTH,

Tony.
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Re: USB workaround

Postby theover » Sat Dec 07, 2019 12:03 pm

Before this project gets demoted to the museum hall where failed machines go, I recall my suggestion works, maybe I'll try and Youtube it for fun, but for people who for some reason need Usb, the way I recall it I can start up, shutdown until the card has been unmounted (to prevent data corrupton), and then hit the reset button. System comes back up and always with USB working.

It might be possible to automate this, though I've looked for a way to get a signal after the unmount portion of shutdown, but that's hard to do for me thus far. If you'd be in the RO portion of the system filesystem mount shutdown program, you could use a user IO to apply the reset, and maybe require a bit of external storage to remember you are then in the second boot. I have another bit of storage on my 7010 setup to remember my debounced supply status (on or off to the powerFET feeding through the supplied 3 Amp supply unit to the boards power pin), which could also be driven by a userIO to be applied after full shutdown has taken effect. That prevents card data loss in every decent system use event: debounced (one step of voltage coming up) power up, decent restart to get Usb reliably to work, and proper all-shutdown with automated power off.

It would somehow still be a shitty system...
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Re: USB workaround

Postby ajtravis » Sat Dec 07, 2019 1:08 pm

theover wrote:Before this project gets demoted to the museum hall where failed machines go, I recall my suggestion works, maybe I'll try and Youtube it for fun, but for people who for some reason need Usb, the way I recall it I can start up, shutdown until the card has been unmounted (to prevent data corrupton), and then hit the reset button. System comes back up and always with USB working.


Hi, theover.

Nice to see some activity here again :-)

One reason for wanting USB is to achieve the original Kickstarter goal of making Parallella as accessible as the Raspberry Pi.
That's why I bought them and why I continue to believe that the Parallella project can be brought back to life!

One problem with your technique is that the BIG heatsinks cover the reset switch...

It might be possible to automate this, though I've looked for a way to get a signal after the unmount portion of shutdown, but that's hard to do for me thus far. If you'd be in the RO portion of the system filesystem mount shutdown program, you could use a user IO to apply the reset, and maybe require a bit of external storage to remember you are then in the second boot. I have another bit of storage on my 7010 setup to remember my debounced supply status (on or off to the powerFET feeding through the supplied 3 Amp supply unit to the boards power pin), which could also be driven by a userIO to be applied after full shutdown has taken effect. That prevents card data loss in every decent system use event: debounced (one step of voltage coming up) power up, decent restart to get Usb reliably to work, and proper all-shutdown with automated power off.

It would somehow still be a shitty system...


GreyTery has kindly donated two working and two bricked Parallella for me to experiment with and I've bought a JTag USB download adapter to try and 'unbrick' his two dead Parallellas and learn something about Vivado in the process. Then, I'll try to understand how uboot initialised the USB PHY and see if there is anything we can do to fix the problem, rather than just mitigate the symptoms. If anyone else is interested, please contact me here or at http://minke-informatics.co.uk

Thanks,

Tony.
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