hau...@keteu.org said:
That being said, I find myself wondering as follows: Suppose that we count
OCXO cycles (at, say, 10 MHz) using one of the MCU's timer/counter
peripherals, and periodically sample the counter value with an interrupt
triggered on the rising edge of the GPS 1pps. Assume
I think a better solution would be to find a very large super cap and
power the BBB from that while giving it a power fail interrupt to quickly
sync the file system.
The advantage of something like the BBB is that it runs Linux so you have a
nice environment in which to run your code. The
On 27 February 2014 08:26, Hal Murray hmur...@megapathdsl.net wrote:
The advantage of something like the BBB is that it runs Linux so you have a
nice environment in which to run your code. The disadvantage of Linux is
that it's complicated and you have things like file systems that can get
In message canx10ha2qmiwc2js8xfn3jat1vxntnnbzxa8-fhq7cybf52...@mail.gmail.com
, Dr. David Kirkby writes:
On 27 February 2014 08:26, Hal Murray hmur...@megapathdsl.net wrote:
Consumer devices like routers and modems run Linux. Does anyone know
how they get around this issue?
They generally don't
On 2/27/2014 6:38 AM, Poul-Henning Kamp wrote:
They generally don't mount their filesystems read/write, but only
read/only.
I've done similar things with FreeBSD in many systems (see: nanobsd)
but I don't have time or clue to figure out how to do that with Linux.
The way TiVo does this is to
Not that I can code anything. I do like several comments I see considering
real life always messes everything up.
The ability to download new code easily. To complement that the ability to
upload the current system with IPs and such. Most routers support this
approach.
The other comment make the
The BBB has 2GB of flash on board (non removable) and has a micro SD socket.
Would not be too hard to keep a backup copy of the OS and apps on the SD card
so that it would be easy to boot from SD and reload the built-in flash if the
BBB fails to boot from the built-in image.
That would not be
The only time there is any exposure is during a write operation. When the
processor board is used to run the 5370, how often is data written and what
is the exposure interval?
I would be willing to bet that Linux already has a power-fail NMI input. I
would bet that you can find out what the
On 2/27/14 6:40 AM, Didier Juges wrote:
The BBB has 2GB of flash on board (non removable) and has a micro SD socket.
Would not be too hard to keep a backup copy of the OS and apps on the SD card
so that it would be easy to boot from SD and reload the built-in flash if the
BBB fails to boot
A number of people have reported issues with the Raspberry Pi Ethernet hardware
when used for NTP, as it is actually a USB-Ethernet bridge and the drivers may
not be all they could be. I have not had problems myself but I do not run NTP
on it.
The Beaglebone Black (BBB) is supposed to be better
Hi Hal,
I've reviewed this a bit and I used the wrong terminology. Either Timer1 or
Timer3 can use the T1CKI input as a clock. Along with that, the CCP1 or CCP2
pin can be used to trigger a capture of the timer in use into the CCPR1 or
CCPR2 register pair. I had considered this as an
Yes the BBB has about twice or more the performance over the Pi except in
graphics. The Pi has a faster GPU. But in the case of an NTP server you
likely would never connect a monitor or keyboard to the computer so the GPU
will go unused.
However the NTP is very un-demanding and will only see on
A number of people have reported issues with the Raspberry Pi Ethernet
hardware when used for NTP, as it is actually a USB-Ethernet bridge and the
drivers may not be all they could be. I have not had problems myself but I
do not run NTP on it.
The Beaglebone Black (BBB) is supposed to be better
Hi Alex,
As these guys have told me, and as I have learned, Rb standards are very
regular, but that doesn't mean they are very accurate. So, unless your Rb
standard was being disciplined to the right frequency you'd probably have to do
some sort of analysis to see the quantizing errors on
it would be interesting to see the accuracy of the 1pps pulses by
comparing them with a second 1pps pulse, which is derived from a
rubidium standard, which on his own does not have quantizing errors,
73
KJ6UHN
Alex
On 2/26/2014 6:03 PM, Bob Stewart wrote:
Hi Mark,
I'm neither an engineer,
If having a battery in the device makes some of you queasy, you could
always put it outside, on the back. But I seriously believe there are ways
to make battery backup which will not leak.
D.
On 27 Feb 2014 06:52, Chuck Harris cfhar...@erols.com wrote:
That fix presumes that the power line
You can fit linux with a comfortable amount of stuff in 20 MB, but you want
more than that for more advanced programs.
You should not use the built in ssd for writing. It has limited writes and
cannot be replaced. Use a card.
You can tailor linux so that it has minimal services but the question
In message CA+9GZUhJLqQ7K-cNXsSzPMgSOH6Oyd774SM_e0=ykljgyd4...@mail.gmail.com
, cheater00 . writes:
If having a battery in the device makes some of you queasy, you could
always put it outside, on the back. But I seriously believe there are ways
to make battery backup which will not leak.
On Thu, Feb 27, 2014 at 12:03 PM, Poul-Henning Kamp p...@phk.freebsd.dkwrote:
Seriously: Keeping the computer alive and eating power is
silly. We just need to find out how to get the Linux configured
correctly.
This is a solved problem. I don't understand why this discussion is
dragging
There is a spin of FreeBSD called NanoBSD, little light on the
documentation but the name pretty much says what it is about.
Either way it looks like the BBB is opening up quite a few minds. Finally a
good combination of power, i/o etc. and not to mention
the two PRU's .. just read up on them
Backup batteries don't make me queasy. The easiest,
cheapest backup battery would be a small 6V 3AH sealed
lead acid battery. It is trivial to make a good float
charger using a 3 terminal regulator and a diode, and
they do not leak, vent, or anything problematic. The
little 6V 3AH packs are
At 11:03 AM 2/27/2014, Poul-Henning Kamp wrote:
Seriously: Keeping the computer alive and eating power is
silly. We just need to find out how to get the Linux configured
correctly.
Exactly. We use the PC-Engines ALIX x86 single board computer stuff
at work, and even I didn't have too much
Do you have experience with FreeBSD on ARM processors?
The simple solution, which may not be possible, is to
make all software on the flash disk RO, and put any part
of the file system that needs to be written onto a RAM
disk... probably should be the /var directory.
The only time the flash
The question can't be answered without knowing what the range switch
does.
In my experience, the cycle that is divided into 360 degrees is the
period
of the input signal regardless of the range switch.
You don't say, but the usual GPSDO produces a 10 MHz signal, unless it's
for a telco
On Thu, Feb 27, 2014 at 6:03 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message
CA+9GZUhJLqQ7K-cNXsSzPMgSOH6Oyd774SM_e0=ykljgyd4...@mail.gmail.com
, cheater00 . writes:
If having a battery in the device makes some of you queasy, you could
always put it outside, on the back. But I
On Thu, Feb 27, 2014 at 6:22 PM, Scott Newell newell+timen...@n5tnl.com wrote:
At 11:03 AM 2/27/2014, Poul-Henning Kamp wrote:
Seriously: Keeping the computer alive and eating power is
silly. We just need to find out how to get the Linux configured
correctly.
Exactly. We use the
On 27 Feb 2014 16:55, cheater00 . cheate...@gmail.com wrote:
If having a battery in the device makes some of you queasy, you could
always put it outside, on the back. But I seriously believe there are ways
to make battery backup which will not leak.
Two batteries, each with a diode and bought
These units multiply the frequency delta and the phase change quoted is
probably 10^n times the actual difference. The output is f + n*delta(f)
I have but do not use a Montronix 100-7 (before the Fluke purchase)
Alan
G3NYK
- Original Message -
From: Bill Hawkins b...@iaxs.net
To:
It is interesting to watch this thread. The most interesting thing is the
fact that no one has asked or answered the basic question: is there a
problem? There are a lot of solutions for what may be a complete non-issue.
Given that Linux and BSD are reliable and stable on standard PC platforms
In message
CAE3hgTcOU5cT3y-T9gYGJz4xeoob9dU8UEM4YgPuwvDWX6Q=6...@mail.gmail.com
, Brian Lloyd writes:
The only time there is any exposure is during a write operation. When the
processor board is used to run the 5370, how often is data written and what
is the exposure interval?
It runs a full
In message 530f740a.7030...@erols.com, Chuck Harris writes:
Do you have experience with FreeBSD on ARM processors?
A little bit, I just started playing with it again recently.
The simple solution, which may not be possible, is to
make all software on the flash disk RO, and put any part
of the
In message ca+9gzujtzon9+uxg1r1brxx8zyv4wnjq22qpsbityako20w...@mail.gmail.com
, cheater00 . writes:
Oh, of course it's not about keeping the computer on at all times,
it's about having a contingency for the 0.1% case when your computer
does not shut down in the assumed time.
You're missing the
There you have the problem in the above sentence from Poul-Henning. It
needs to be yank the power proof. Because that is the way the 5370 shuts
down.
That said the board and software thats been created by one person is simply
amazing and well done.
We are discussing a fine adjustment. Batteries
Hi Brian,
it's less about caching pending writes to file handles that are
waiting inside the system. That's most likely to work well within a
short period of time.
The issue is if you're using the system to its full extent. Among
others you'd like to write applications for the BBB that enhance
Most routers use a similar model and can save important settings but still
recover from a crash with no problem. There are several router distros that
are good examples on how to do it. I would suggest looking at Voyage Linux
http://linux.voyage.hk/ for an example. They have a specific versing
In message CA+9GZUgrLw05f=pvh5tji+vlkfstwatibcpe1t3xfgwq2+s...@mail.gmail.com
, cheater00 . writes:
Note that all of the shortcuts I mentioned above are fairly reasonable
defaults that save days of work per project for no improvement in
reliability, since, after all, a suitable battery only costs
On 27 February 2014 17:31, Chuck Harris cfhar...@erols.com wrote:
Backup batteries don't make me queasy. The easiest,
cheapest backup battery would be a small 6V 3AH sealed
lead acid battery. It is trivial to make a good float
charger using a 3 terminal regulator and a diode, and
they do
I have worked on lots of equipment that was sealed with
a SLA inside, and I have never seen any sign of corrosion.
Only times I have seen a problem is in the case of UPS's that
were left discharged in unheated warehouses... the electrolyte
froze and the battery cases bulged greatly, but still no
Totally agree with Chucks comment I have opened many system that have been
in service at least 5 years virtually no evidence of corrosion.
I have however opened system that do not manage the batteries correctly and
they are a mess.
But we really are drifting away from the main thread. Just want to
But we really are drifting away from the main thread.
Yes, indeed. It's time to wrap up the operating system and file system tangents
and get back to time frequency.
Those of you with positive suggestions for improvements of the 5370 processor
mod kit can email them to John Seamons
Has anyone found a suitable replacement or a source for the fan/blower in the
HP53131A ? I have talked to Agilent and the fan/blower is not a seperate item,
its part of the power supply board.
TRY FREE IM TOOLPACK at
Now that you mention it, I have another small embedded system with 64MB of RAM
that runs Linux 3.4 just fine off a flash drive, so running a RAM disk in 512MB
should be feasible.
Didier KO4BB
On February 27, 2014 9:12:45 AM CST, Jim Lux jim...@earthlink.net wrote:
On 2/27/14 6:40 AM, Didier
The only time there is any exposure is during a write operation
That is not true. By default, Linux updates the last access time for each file
it reads. The last access time is stored with the file, so each file read
actually causes the file to be written to as well, opening the door to all
And after all that, *STILL* no one has been able to answer the question,
Is there a problem that must be solved? Oh, lots of supposition, rules of
thumb, boatloads of experience, etc., but still no determination that
something really needs to be solved.
One of the interesting things that came
Looks like I win the fiver.
Johns created a great board for the 5370.
However you can't just turn the 5370 off as this lazy person is used to.
Plus I really have to say after a full day of time-nuttery I won't remember
to shut the linux down.
So thats the need good old shutdown controlled by the
Hi
I realize this is a bit off the main topic of … but here goes:
Is there any performance data on how the card does with a 5370A and / or a
5370B compared to the original CPU on the exact same box? Put another way -
does the counter get better or worse with the new card? I realize that an A
On Feb 28, 2014, at 4:34 PM, Bob Camp li...@rtty.us wrote:
Is there any performance data on how the card does with a 5370A and / or a
5370B compared to the original CPU on the exact same box? Put another way -
does the counter get better or worse with the new card? I realize that an A
On Thu, Feb 27, 2014 at 9:03 PM, paul swed paulsw...@gmail.com wrote:
Looks like I win the fiver.
Really? You power-failed it and corrupted the file system?
Johns created a great board for the 5370.
However you can't just turn the 5370 off as this lazy person is used to.
Really? You
Le 28 févr. 2014 à 02:55, Brian Lloyd a écrit :
And after all that, *STILL* no one has been able to answer the question,
Is there a problem that must be solved? Oh, lots of supposition, rules of
thumb, boatloads of experience, etc., but still no determination that
something really needs to
In message 7984e000-057c-4790-9d20-e4dac1f60...@rtty.us, Bob Camp writes:
Is there any performance data on how the card does with a 5370A and / or a
5370B compared to the original CPU on the exact same box? Put another way -
does the counter get better or worse with the new card? I realize that
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