Amateur electronics in danger due to lack of DIP ICs - Page 10

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Re: Amateur electronics in danger due to lack of DIP ICs
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"their advice" - you mean someone on the forum or official rpi advice

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But your work still works on a 4G board? Don't tell me you didn't do a  
back up?

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I don't think they have shares, and anyway I'm no raspberry fan boy. I  
just use their cheap hardware and know enough to customise my software  
and not loose it between board revisions. The one thing they have got  
right is that the current version of their OS runs on all the old  
versions of their boards, so I can compile once and run on my old boards.

Obviously your experience is different, but I suspect it is your own fault.

Re: Amateur electronics in danger due to lack of DIP ICs
On a sunny day (Tue, 2 Mar 2021 10:26:16 -0000 (UTC)) it happened Jim Jackson

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Officially they have nothing.

But officially they bring out one experiment (kindly named so) after the other,


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Of course I have every card backup on a regular basis, on many media actually
As I write software things change all the time

So card for Pi4 4G did not work in Pi4 8GB

Made a copy and did that apt blah blah number
Sucked


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Why would I want to run a current version for RP4 8GB on a RP1?


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You can suspect anything you want.
I gave out a warning, and for me I have enough of raspberry crap coders.




Re: Amateur electronics in danger due to lack of DIP ICs
On Sun, 28 Feb 2021 16:10:53 GMT, Jan Panteltje

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Oddball question here- I  have a RPi that I run Octoprint on to
control a couple of 3D printers. Was having some problems getting a
second camera going so I did a poorly advised install/update/upgrade
and ended up bricking the Pi. No real problem, restored it from
backups on a new SD card, but the original card now cannot hold the
original image, it's a small number of bytes short (but still
functions).

Any idea what happened? I tried obvious things like Etcher and the SD
card consortium official format tool but no change. Good quality
Kingston 16G card. Hardware failure associated with all the writing?  

Not worth a whole of effort but it bugs me.  

--  
Best regards,  
Spehro Pefhany

Re: Amateur electronics in danger due to lack of DIP ICs
On a sunny day (Wed, 03 Mar 2021 15:59:37 -0500) it happened Spehro Pefhany

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This is a known problem, I ran into it and found others with google with the same problem.
The Pi1 (old version) somehow messes up the card.
What I did IIRC is get the card that no longer booted,
put it in the laptop, mounted the 2 partitions, and all seemed well.
Could read all data.
Got the backup image an put that with dd on the same card, now it booted.
Backup was 200 days oldthough....
Later I got the important data (logfiles ship and plane data temperature humidity radiation etc)
from that not really 'defective' card and copied it to the new one.
??

I now only use Samsung SD cards so I took the opportunity to dd to a bigger size card
and let raspi-config extend the filesystem.
Been running OK since.
 root@raspi73:~# df
Filesystem     1K-blocks     Used Available Use% Mounted on
rootfs          30709628 14214556  15096804  49% /
/dev/root       30709628 14214556  15096804  49% /
devtmpfs          216132        0    216132   0% /dev
tmpfs              44880      236     44644   1% /run
tmpfs               5120        0      5120   0% /run/lock
tmpfs              89740        0     89740   0% /run/shm
/dev/mmcblk0p1     57288    19000     38288  34% /boot
root@raspi73:~# uptime
 08:53:52 up 20 days, 18:34, 11 users,  load average: 1.79, 1.84, 1.83
root@raspi73:~# uname -a
Linux raspi73 3.6.11+ #371 PREEMPT Thu Feb 7 16:31:35 GMT 2013 armv6l GNU/Linux
root@raspi73:~#  

2013 :-)
And, as you can see, I load that stuff to the maximum.
Previous uptime before the card problem was >200 days.
It went wrong when I moved house and all sort of things got power disconnected and thrown in boxes...
In the new place it would no longer boot...

So what was wrong with the card? Nothing,  
could also mount the 2 partitions on the laptop and read all files.  
Maybe some bit in the bootsector changed?






Re: Amateur electronics in danger due to lack of DIP ICs
On 2/26/2021 3:04 AM, John Walliker wrote:
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RT support is independent of the storage media from which opcodes
are fetched; the media has predictable performance levels so it
falls out of the equation.

But, the hosting OS needs to be designed with RT in mind.  This
affects scheduling decisions, resource allocation strategies, "priority"
assignment, etc.

Sadly, HRT is often confused with "real fast"; that's not the driving
criteria.  Likewise, associated with "having significant consequences
for missed deadlines".

There are lots of HRT tasks that aren't fast, have LONG deadlines
(with relatively low computational burdens), etc.  And, many whose
consequences of a missed deadline are just a shrug.

A first-order approach to designing for HRT is:  when the deadline
for a task comes, kill the task (if it hasn't met its deadline,
there's NO POINT in continuing)!

By contrast, SRT suggests you keep working on tasks that miss their
deadlines as there is still some "value" to be had in their completion,
even if "late".

And, of course, any task WITHOUT a deadline is simply not RT!

:>

Re: Amateur electronics in danger due to lack of DIP ICs
On 26/02/21 10:04, John Walliker wrote:
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Anything with caches or interrupts makes it difficult to
guarantee timing, as does multiplexing/timeslicing multiple
threads onto a single core.

Much easier if you have enough decent cores (i.e. ARM level
not LUT level!), inter-core hardware for comms, and - most
importantly and rarely - a decent parallel processing concept
and tools.

The XMOS xCORE devices have up to 32 core, 4000MIPS per
chip (expandable), an IDE that tells you the exact number of
cycles it takes to get from here to there[1], and the xC
language based on parallel processing, messaging, and avoidance
of C features that makes multiprocessing "error prone".

It has a solid theoretical and industrial pedigree: Hoare's
Communicating Sequential Processes from the 70s, then the
Transputer and Occam from the 80s, and quite a few concepts
seen in other modern languages like Rust and Go. XMOS has been
doing this since, I believe, 2007, and you buy the parts at
DigiKey etc.

It can, for example, use /software/ to input/output and
process a 100Mb/s ethernet serial bitstream. (Whether that is a
sensible use of silicon is a separate matter; what's important
is that it can be guaranteed at all!)

[1] i.e. no such it and see and hope you stumbled across
the worst case

Re: Amateur electronics in danger due to lack of DIP ICs

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Just curious about which TI processor architecture you're talking about.  I
 figure you mean the launchpad series of eval boards, which support several
 different processors.  I've been working with the C2000 architecture for 1
8 years, and about to give up and go with the ARM flow.
-Jim

Re: Amateur electronics in danger due to lack of DIP ICs
On Thu, 25 Feb 2021 07:37:32 -0800 (PST), Jim MacArthur

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I don't recall.  I've slept since then.  It's definitely called a
Rocket Board.  I'm looking at the box on the shelf and there's a cute
little rocket on the side.  Too lazy to get up to look in the box.

John

Re: Amateur electronics in danger due to lack of DIP ICs
John Larkin wrote:

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No idea, but here might be a clue:


https://www.youtube.com/watch?v=Zh3Yz3PiXZw


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Does one need a steady hand to solder a 1.27mm pitch SO-16? It's not 0402.

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You have the Kapton foil to protect the surroundings. With a preheater,  
the required amount of the soldering heat is actually not that big.
The aha moment comes when one discovers that the hot-air gun has more  
settings than min and max.

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I wet the pads with solder, put the part next to the footprint to heat  
up the board and the part, grab it with tweezers, put it in place and  
heat everything just enough to melt the solder bumps. Then I gradually  
increase the distance to cool it off gently, and I'm done. TSSOP is  
easy. MSOP requires a microscope for proper placement. The parts  
mortality rate during prototyping is relatively high, so these rework  
skills are essential.

    Best regards, Piotr

Re: Amateur electronics in danger due to lack of DIP ICs
snipped-for-privacy@neverland.mil says...
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I use the Kapton tape.  I cover a wide area and then take an Xacto knife  
and cut out around the parts I want to remove or install using the hot  
air wand.  It is interisting to see a part that you use the paste and  
hot air on just wiggle its self into position with the right ammount of  
heat and air.

Sometimes I use the solder paste for that and sometimes a very fine tip  
iron.  It just takes some practice to learn how much heat and air flow  
to use on the parts.  As I am just a hobbiest I find the $ 80 hot air  
rework stations on ebay do decent job.  Same as the Amscope $ 200  
microscope.  Now If I was making a living at it, the Mantis and a $ 500  
or $ 1000 hot air station and even one of the hot plate things would be  
the way to go.

Re: Amateur electronics in danger due to lack of DIP ICs
On Wed, 24 Feb 2021 21:42:17 +0100, Piotr Wyderski

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Sounds complex. I just use a soldering iron.

--  

John Larkin         Highland Technology, Inc   trk

The cork popped merrily, and Lord Peter rose to his feet.  
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Re: Amateur electronics in danger due to lack of DIP ICs
John Larkin wrote:
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Me too.  With maybe a hotplate underneath the board if the part has a  
power pad.  The mortality rate with just hot air is too high.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: Amateur electronics in danger due to lack of DIP ICs

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There are devices which support the board over a hot air underside  
pre-heat and then a hot air gun reflows the top side component and  
performs the solder operation.  They are pretty good for small PCB  
assemblies.

Re: Amateur electronics in danger due to lack of DIP ICs
On 2/24/2021 7:01 PM, snipped-for-privacy@decadence.org wrote:
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My Leister has a frigging different nozzle for each package type,
effectively.  So, the heat flows where it should and not where it
shouldn't.

But, you can fry a device with hot air just like you can fry one
with an iron -- if you don't know what you're doing!

Hence, it's far easier for me to let a line that is set up to
do this sort of stuff -- day in, day out -- deal with the hassles.

Re: Amateur electronics in danger due to lack of DIP ICs
On Mon, 22 Feb 2021 08:24:38 -0800 (PST), Deane Williams

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It's getting very difficult to even get surface mount ICs these days
too !

Re: Amateur electronics in danger due to lack of DIP ICs
On 2/25/2021 6:45 PM, boB wrote:
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The trend is towards higher levels of integration and making that integration
more affordable at lower quantities.  There will likely be a point where
it will be impractical to fabricate at the "discrete" level that has been
possible to date.

In the mid 70's, an older colleague told me DIPs would be disappearing.
My only other experience with "integrated" devices was the flatpacks
common in MIL designs -- so I was curious as to what NEW package
styles would evolve.

[Of course, back then, I was concerned with *using* the packages and
not thinking about the fab issues that went into their design/creation!]


Re: Amateur electronics in danger due to lack of DIP ICs
On Monday, February 22, 2021 at 8:24:44 AM UTC-8, Deane Williams wrote:
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f stuffed into a "breadboard", is rapidly decreasing. I have not been in a  
position where I needed to prototype a new design (as a hobbyist) in years.
 But now I do and while searching for a >10MSPS A/D and a FIFO memory to us
e with it I am seeing nothing available with pins. What are home builders d
oing these days about this? Is there a company that will solder these surfa
ce mount chips onto a small circuit board for a reasonable price? I bought  
one of those SSOP adapter boards and there is no way I can solder those tin
y pins without bridging solder over the gap between pins. What are people d
oing?

Paste Flux is the "secret sauce" that greatly reduces molten tin-lead's sur
face tension, and spreads the heat more evenly so that solder won't bridge  
(not even fine pitch).   Apply the flux paste (rosin) to the TSSOP adapter  
board, place the chip, then apply more flux paste.   Use a clean tip, and u
se just a tiny amount of solder on the corners pins, then drag the solderin
g iron tip from the corners to the center pins.  Even if the tip is a broad
 point, and bridges 2-3 pins; the solder behind it won't bridge.  Not need  
for solder paste or hot air tool (although a hot air tool is handy if you e
ven need to remove a chip).  YouTube has plenty of "How To" videos on the t
opic.   ~TM

Re: Amateur electronics in danger due to lack of DIP ICs

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  "What are people doing"  They refrain from soldering when they do  
it as badly as you do and get someone that can solder them onto  
carrier boards without bridges to wick away or use a method to fix  
what you broke instead of not breaking it to begin with. (read shitty  
soldering methods and skills)  Blobby Bobby is NOT the right way.  It  
is the way poor solder skills assemblers use to attack a problem they  
caused.

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