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Microcontrollers / Re: A couple questions about Milk-V Duo boards
« Last post by brucehoult on Today at 04:18:18 am »
I think you have to choose one or the other at boot time, but I don't know.

Also see:

https://github.com/orangecms/sg_boot "loader for CVItek/Sophgo SoCs (CV1800B, SG200x)"

He said today initial stuff is working and asked for collaborators.

https://t.me/riscv/1/20904

https://t.me/riscv/1/20913
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Programming / Re: Linux Dependency Black Hole
« Last post by tatel on Today at 04:17:04 am »
If you don't want to get into dependency hell, just stick to apt and what is in the repositories for the release you installed. Package maintainers did that work for you. To make a package for Debian implies you have full knowledge about all the Debian policies, etc, and to learn it means a lot of work.

I also think things are getting worse. The reason are all those pesky new/better/wonderful ways to install software... that are full of shit. They don't want to learn how to create debian packages, or think they will make some money going that way, or fame/glory/whatever, so they have to invent the wheel again and again. But, while apt is almost the perfect wheel, those new wheels, well, not so much.

AppImage can work. I don't like it however. Docker could be useful if you have servers and want/need to migrate not just the software, but also the contents, from one server to another. What I can't swallow is pip. Use pip to install any python thing, and odds are things will be messed up sooner rather than later, because you have now python things installed, unknown to apt. Pip would like to be half the good apt is. And you'll probably will forget you installed that thing with pip. Then a rough ride will begin.

tar.gz packages? To me, that means source code to be built. If you do so, you'll need to learn previously about the dependencies, and build that dependencies first. And the dependencies of the dependencies. And so on an on... until you have built all what's needed. All should go into a separate partition. There used to be a /local directory just for that partition to be mounted there.  That way you can have different versions of libraries, etc, needed to do the work, and those binaries can be easily preserved if you want to upgrade the rest of the system. I used to do that only for versions of software with new features/fixes that I needed, and I get it back to be installed with apt as soon as the corresponding debian package for "stable" is released.

But, often, the main reason is just user ignorance and unwillingness to read any documentation. Debian has quite good guides, and anyone that did read about the sources.list file, would know that metrologist, in that other thread, is getting messages about hits from two different repositories, one of them for bookworm, the other one for jessie. So, no wonder he got a dependency hell. He just messed things, first, choosing to do an upgrade when the easiest way, not having anything functional on that system, would have been to go for a clean install. Then he modified /etc/apt/sources.list without knowing what he was doing (because he couldn't be bothered to read the guide). Then he complains "Linux sucks". LOL.

Easiest solution: clean install with just the defaults. After that, use just APT to install any packages. If some software couldn't be installed with APT, it just means that software isn't mature enough, and it should be avoided like the plague, until you know what you are doing.
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Beginners / Re: 555 driver and Transformer questions
« Last post by Andy Chee on Today at 04:14:12 am »
Transformers do have a hard limit at the lower end, going below will result in core saturation.

The upper limit is much softer and won’t damage the transformer. Basically you hit the transformer’s resonant frequency peak, then the response tails off like a low pass filter.

Ideal waveform is 50% duty cycle. This ensures there’s no net DC that will contribute to core saturation.
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Beginners / Re: XOR gate problem with GND
« Last post by amyk on Today at 04:11:37 am »
Here is what a real RTL NOR gate looks like, from a 1968 databook.

They wouldn't use that many transistors if they didn't need to. Transistors were much more expensive back then too!
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If desoldering a few VFD pins doesn't go well, I'd suggest getting a decent handheld vac desoldering tool. I find braid is hard on boards, for heat and abrasion on larger TH pins. Unless you have a good technique.
We used Soldapullt back in the day they were good if greased well. The chinese ones I hear many are useless. The test was to see how much suction it had on your finger, the piston should move slow if the tip is blocked.
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Buy/Sell/Wanted / GPIB Breakout Board
« Last post by dazz1 on Today at 03:52:58 am »
I have made my own piece of test equipment.  It is a GPIB breakout board.  It plugs directly into the HP Logic Analyser cable so no messing around with individual probes.  Just plug and play.  It would be easy to make up a cable to adapt the GPIB breakout connector to another make/model of LA.

In addition, the signals are also exposed on a separate header.

I have made the first GPIB breakout board and updated the pcbway share project, available for ordering your own board ( [url=https://www.pcbway.com/project/shareproject/GPIB_Break_Out_Board_f7812b3e.html]PCB from PCBWay[/url] ).

I now have 4x spare boards and parts available for sale.  Cheaper than buying parts and boards for one, like I have done.

I am selling the parts as a kit for assembly.  Just requires a soldering iron and some time. 

To calculate the shipping cost, go to this website: https://www.nzpost.co.nz/tools/rate-finder/sending-internationally/parcels] [url]https://www.nzpost.co.nz/tools/rate-finder/sending-internationally/parcels[/url]  for a Size 1 box from Wellington. 

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Quote
In the pics I can see right-most digit has "C" segment stuck on, is that the only malfunction in the pics?

In the pics I posted, if I'm not mistaking, the commas and/or periods are wrong, and it's not showing "MHz".

Sporadically, digits four and five are wrong, commas and/or periods are wrong, and, usually, in all cases (I believe) "AUTOOTRIG" is displayed.

Unfortunately I don't have a solder VAC just solder braid and a solder plunger (the manual pump and push button release type).

I think to save time and reduce the risk of damage, I may just move forward with replacing the HV518 chip.

I was hoping to figure out which data line and G line toggled which segment(s) in each digits, and not only gain some knowledge, but provide the information back to this thread for others to learn from and/or help diagnose issues on their end.

Since I have the logic analyzer out and the display sitting outside the unit, I'll probably measure the G lines on the logic analyzer; and then move forward with replacing the chip.
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Beginners / Re: 72C5 - What Is This?
« Last post by amyk on Today at 03:48:02 am »
How is it connected to other components? A bigger picture of its surroundings?
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For posterity - the undervoltage cutoff seems to only be hooked up to the ~POK pin and not the GATE pin of the IC  |O
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Beginners / Re: Replacing SRAM IC with Flash
« Last post by amyk on Today at 03:44:27 am »
There's been various topics on here before about replacing the Dallas NVRAMs with FRAM, is that where you got the idea?
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