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by Aydan
Mon Jan 21, 2019 5:15 pm
Forum: Troubleshooting
Topic: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?
Replies: 18
Views: 288

Re: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?

Weeeelllllll, if you want to do it old school, then you can still do it in C :D
Python just provides so many high level libraries that it kind of hurts to see code not using what python can offer.

Regards
Aydan
by Aydan
Sun Jan 20, 2019 8:24 pm
Forum: Troubleshooting
Topic: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?
Replies: 18
Views: 288

Re: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?

Your code probably works relatively stable, but is far from optimal: #1 If you want to average the speed, why do you discard samples which were received during your display update? #2 why do you use individual variables for the speed samples? Please read up on python lists. #3 you are again using sl...
by Aydan
Fri Jan 18, 2019 4:13 pm
Forum: Troubleshooting
Topic: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?
Replies: 18
Views: 288

Re: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?

Thanks for further hints. Once you guys mentioned the serial was buffered I found a solution. Just adding to the end of the loop :- ser.flushInput() did the trick. It flushes the buffer so when I start the next loop I get the latest NMEA string Now I get the latest NMEA string regardless of how lon...
by Aydan
Thu Jan 17, 2019 1:36 pm
Forum: Troubleshooting
Topic: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?
Replies: 18
Views: 288

Re: GPS via USB data gets corrupted if the program loop delay exceeds incoming rate. Is this a TTYUSB0 Cache problem?

If the serial data is put into a ring buffer, how can I disable it, so that I read GPS NMEA strings live as they arrive and not out of some buffer. I guess what I have at present is a FIFO type buffer and what I need is a LIFO one. cheers There is always a buffer. You can reduce it to 1 byte, but t...
by Aydan
Thu Jan 17, 2019 1:22 pm
Forum: Troubleshooting
Topic: Rpi3 hangs after 3 hours
Replies: 11
Views: 210

Re: Rpi3 hangs after 3 hours

@jamesh: would it be possible to include the status of the undervoltage flags into the kernel oops report? This might make things easier for debugging USB faults due to undervoltage.
by Aydan
Thu Jan 17, 2019 1:15 pm
Forum: General discussion
Topic: New SystemD Vulnerabilities
Replies: 14
Views: 1011

Re: New SystemD Vulnerabilities

DirkS wrote:
Thu Jan 17, 2019 12:21 pm
I think they were already in the Raspbian updates I installed yesterday.
Yes, the fix is available since yesterday.
by Aydan
Thu Jan 17, 2019 12:17 pm
Forum: General discussion
Topic: New SystemD Vulnerabilities
Replies: 14
Views: 1011

Re: New SystemD Vulnerabilities

Debian has rolled out the fix already, so Raspian should not be far behind.
by Aydan
Thu Jan 17, 2019 9:46 am
Forum: Advanced users
Topic: can i Replace Matlab & Simulink -with Octave - since the later one is Open Source
Replies: 2
Views: 94

Re: can i Replace Matlab & Simulink -with Octave - since the later one is Open Source

the octave package for armhf is in the debian stretch repos, so it should be in the raspbian repos as well.
"sudo apt install octave" should be enough.

Regards
Aydan
by Aydan
Thu Jan 17, 2019 8:37 am
Forum: Advanced users
Topic: (solved) Disable red power led on 3B+
Replies: 11
Views: 2203

Re: (solved) Disable red power led on 3B+

barsznica wrote:
Thu Jan 17, 2019 12:10 am
viewtopic.php?t=91440#p639363,
says, the Power LED is connect to gpio 35 (BCM numbering).
This is for the B+. not the 3B+
by Aydan
Thu Jan 17, 2019 8:33 am
Forum: Advanced users
Topic: Setuping up on Virtual Box then Converting back to IMG
Replies: 3
Views: 111

Re: Setuping up on Virtual Box then Converting back to IMG

I think the easiest way is to use multiarch and qemu on a debian base system and chroot into the raspbian root file system.
I did this for setting up the sd card for my Pine64 on an Intel Laptop.
for reference see here:
https://wiki.debian.org/Arm64Qemu
Should work the same for armhf

Regards
Aydan
by Aydan
Wed Jan 16, 2019 4:28 pm
Forum: Troubleshooting
Topic: Clone and “Error: Can't have a partition outside the disk!”
Replies: 38
Views: 1175

Re: Clone and “Error: Can't have a partition outside the disk!”

Just to clarify:
what is the filesystem size of your original SD card? (df -h)
If that is bigger than what fits on your new sd card, then you have to resize at least the file system before cloning.

fixing the partition table will not magically fix/resize your broken filesystem.
by Aydan
Wed Jan 16, 2019 3:07 pm
Forum: Troubleshooting
Topic: Clone and “Error: Can't have a partition outside the disk!”
Replies: 38
Views: 1175

Re: Clone and “Error: Can't have a partition outside the disk!”

I think the original problem is that you 2nd 64GB card is a bit smaller than the original card. I have plenty of spare cards for this. Stock included 64 32 3 x16 ‘s 2 x 8, 4 x 4gb’s 2 x 2gb’s Sorry, that above from me was meant to be that, that is my complete stock of cards..the 64 gb is not a 'spa...
by Aydan
Wed Jan 16, 2019 1:52 pm
Forum: Troubleshooting
Topic: Clone and “Error: Can't have a partition outside the disk!”
Replies: 38
Views: 1175

Re: Clone and “Error: Can't have a partition outside the disk!”

I think the original problem is that you 2nd 64GB card is a bit smaller than the original card. This would cause the root partition to "stick over the end" of the cloned card. Running fsck on this partiton on the cloned card should give you an error in this regard. also check the partition layout wi...
by Aydan
Tue Jan 08, 2019 11:11 am
Forum: General discussion
Topic: Using "all the cores" of the RPI?
Replies: 23
Views: 746

Re: Using "all the cores" of the RPI?

Hi Chris, no need to split it into different programs, have a look at python's multiprocessing module . Instead of starting a new thread, it starts a "new" process, which is a copy of the original process, and branches into the given function. The handling is very similar to threading, but the data ...
by Aydan
Mon Jan 07, 2019 11:52 am
Forum: General discussion
Topic: Using "all the cores" of the RPI?
Replies: 23
Views: 746

Re: Using "all the cores" of the RPI?

Multithreading in python is not truly parallel, due to the GIL (Global Interpreter Lock). It is more like serial multithreading in that only one thread can be active at a time, the others will be sleeping. So python multithreading is mostly useful waiting for IO, not for compute bound stuff. I sugge...
by Aydan
Thu Dec 20, 2018 2:25 pm
Forum: Troubleshooting
Topic: Port "busy" when trying to send AT commands to modem
Replies: 3
Views: 87

Re: Port "busy" when trying to send AT commands to modem

@scottk
if you are running Stretch with Desktop, it could be that ModemManager has grabbed the ports.
try

Code: Select all

sudo systemctl stop ModemManager
and see if the ports are then acessible.

Regards
Aydan
by Aydan
Sat Dec 15, 2018 9:33 pm
Forum: Advanced users
Topic: enabling ssh wia /boot/ssh when nfs booting
Replies: 4
Views: 345

Re: enabling ssh wia /boot/ssh when nfs booting

I was being stupid.
I used a raspbian sd card mounted into my nfs share folder, with boot mounted into .../boot and forgot to set crossmnt in /etc/exports.
So NFS didn't expose the contents of the boot partition to the zero.
Now it worked an the sshswitch service "ate" the ssh file.

Regards
Aydan
by Aydan
Thu Dec 13, 2018 5:30 pm
Forum: Advanced users
Topic: Wake from halt when gadget booted?
Replies: 5
Views: 264

Re: Wake from halt when gadget booted?

this is what "udevadm monitor" gives me this when starting rpiboot after halting raspbian on the zero: KERNEL[563564.547887] remove /devices/pci0000:00/0000:00:1d.0/usb3/3-1/3-1.8/3-1.8.5/3-1.8.5:1.0 (usb) KERNEL[563564.547968] remove /devices/pci0000:00/0000:00:1d.0/usb3/3-1/3-1.8/3-1.8.5 (usb) UDE...
by Aydan
Thu Dec 13, 2018 9:07 am
Forum: Advanced users
Topic: Wake from halt when gadget booted?
Replies: 5
Views: 264

Re: Wake from halt when gadget booted?

Shorting the run pin works, but this requires extra hardware to be controllable by the host, which does not have digital outputs.
I was looking to do this via the USB link, so i don't need extra hardware and could do it form the USB host.
by Aydan
Wed Dec 12, 2018 4:02 pm
Forum: General discussion
Topic: Set Python3.7 as Default Python and Set pip
Replies: 2
Views: 283

Re: Set Python3.7 as Default Python and Set pip

to get the path to python3.7 type

Code: Select all

which python3.7
then update the symlink for /usr/bin/python3 to point to your python3.7 binary.

Do NOT change the symlink of /usr/bin/python to point to python3, this will break any packages which depend on python2.x.
by Aydan
Wed Dec 12, 2018 12:15 pm
Forum: Advanced users
Topic: enabling ssh wia /boot/ssh when nfs booting
Replies: 4
Views: 345

Re: enabling ssh wia /boot/ssh when nfs booting

Well, NFS doesn't have partitions.
And really, it shouldn't matter. If /boot/ssh exists, then the mechanism should work.
Which script actually does activate the ssh daemon?
by Aydan
Wed Dec 12, 2018 10:46 am
Forum: Advanced users
Topic: enabling ssh wia /boot/ssh when nfs booting
Replies: 4
Views: 345

enabling ssh wia /boot/ssh when nfs booting

Is the ssh file to enable ssh deamon only read on first boot? Or can this be done lateron as well?
I set up a pi zero for usb gadet booting from NFS yesterday, and the ssh file in boot did not activate the ssh daemon.
by Aydan
Wed Dec 12, 2018 9:59 am
Forum: Advanced users
Topic: Wake from halt when gadget booted?
Replies: 5
Views: 264

Wake from halt when gadget booted?

Is there a way to restart a PiZero from halt when booted via usbboot?
I did get a reaction from usbboot when I ran it against a halted PiZero, but it didn't start pulling files.
by Aydan
Mon Dec 10, 2018 9:35 am
Forum: Camera board
Topic: Camera module reliability issue
Replies: 6
Views: 745

Re: Camera module reliability issue

This issue seems to have resolved itself for me.
I've not had a hang up for a few days now, where before I had a hang daily.
by Aydan
Thu Dec 06, 2018 3:48 pm
Forum: Troubleshooting
Topic: [Closed] Program working with camera feed uses a lot of cache mem.why isnt it cleared after the program is done
Replies: 4
Views: 119

Re: Program working with camera feed uses a lot of cache mem.why isnt it cleared after the program is done

and the cache mem. drops down by those ~300mb, but could anyone explain to a beginner why isnt it done automatically? Or is it possible to make sure it is? please read this: https://www.linuxatemyram.com/ The short of it is: Linux keeps data in RAM even if it is no longer used, as long as no other ...

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