[From a couple of weeks ago...]
Opto-isolater? Why not just use fiber cable between cards.
I have only ever seen point-to-point versions, I needed 7 cards connected.
You can make a multi-drop setup with 2n unidirectional optical links. The
trick is to send all the links to a common node
bownes wrote:
I love those Hammond boxes until I have to pay the bill. The one for my n2pk VNA was about $28.
I find the non-parallel sides really inconvenient on the Hammond boxes.
It means you can't mount the boards to the sides of the box, just to
the bottom or the top.
COMPAC
Hammond also make aluminum boxes from extrusions. These have parallel
walls and there are slots for mounting PCBs. I don't think we need to
select a standard box. only a standard PCB siz. If you pick 100mm
x 160mm that is a standard eurocard size and there are many boxes that
hold 100 x 160mm
I particularly like the Box Enclosures brand extruded aluminum boxes. The
series 2 and series 3 enclosures take 100mm wide Eurocard boards perfectly.
They are very easy to machine if you want D holes for BNC connectors, etc.
They're also extremely high quality and cheap! Newark sells them and I
On 12/23/2010 03:05 AM, Chris Albertson wrote:
On Wed, Dec 22, 2010 at 3:32 PM, Poul-Henning Kampp...@phk.freebsd.dk wrote:
I used a shared opto-isolated async bus. You need two optocouplers
per microcontroller, and one place you power the shared bus, and
you're all set.
I have yet to see
Really I just used I2C in my write-up as a place holder. I you say
nothing no one ever says a blank paper is wrong and suggests something
better.
Using a serial interface is nice, but I2C is not the one of my choosings.
I'd go for plain serial interface, RS-232 like, but not necesserilly
I hadn't considered the possibility of using an embedded processor board.
That is an interesting possibility. The ability to run linux on it, as well
as have DSP and FPGA in hand would certainly up the ante a bit. A 400 mhz
DSP and 25Mhz CPU would be more than enough processing power.
Just
El 23/12/2010 16:11, Bob Bownes escribió:
I hadn't considered the possibility of using an embedded processor board.
That is an interesting possibility. The ability to run linux on it, as well
as have DSP and FPGA in hand would certainly up the ante a bit. A 400 mhz
DSP and 25Mhz CPU would be
Bob,
That is what I'm thinking also but when you say the main board has
nothing on it but a few connectors then why have a main board?
All the functions of the main board can be placed in a plug-in that is
easy to change as technology moves. Rather then a main board you have
just a cable, maybe
El 23/12/2010 19:08, Chris Albertson escribió:
There are some really great embedded processors out. The problem is
software. If you pick some exotic processor then you will be the
only one to write software for it. To avoid that I'd pick one that
most people already know. The bottleneck in
Gosh, Javier, I went to your website, and found one of my favorite peeves:
it says low cost without a hint of the price. I've found that this
combination usually means way out of my price class or, if you have to
ask, it's too high, or low cost for a big company with a research
budget.
Sorry, just
Simply ask ;)
Seriously, I think that this kind of things are not too much money, like
for example the ADSP-BF537 Stamp from Analog Devices
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detailname=ADZS-BF537-STAMP-ND
We are not building this one in large quantities, but we've used it
I think the ADSP-stamp is about $100 overpriced at least. there are boards
available with more capability for less. There is an old saying that noone
was ever fired for buying IBM, maybe that's why AD charges what they do.
meantime, microchip is laughing all the way to the bank...
That said, your
I suppose that it all depends on the production quantity :) Well, the
ADSP-BF537 EZKIT is quite more expensive and does not provides too muchs
not included in the STAM... and if you like to see thing really
expensive, this is an example:
yikes! only for us government contractors.
Don
Javier Herrero
I suppose that it all depends on the production quantity :) Well, the
ADSP-BF537 EZKIT is quite more expensive and does not provides too muchs
not included in the STAM... and if you like to see thing really
expensive, this is an
Chris Albertson wrote:
I wrote some more ideas, I'm trying here to write what might later,
after some edits become a consensous document. that captures what
most people want. Edit away, maybe some of this will make it to the
web site...
++
Here is
The use of i...@c that I proposed was ONLY for module-to-module
communication. I wrote that none of the internal chips in a module
were to be exposed to the i2c bus. A module may very well have it's
own internal bus but that design detai needs to be hidden from the
rest of the system.
In an
.
From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wed, December 22, 2010 2:58:10 PM
Subject: Re: [time-nuts] Form factor
The use of i...@c that I proposed was ONLY for module-to-module
communication. I wrote
On Tue, Dec 21, 2010 at 11:50 AM, bownes bow...@gmail.com wrote:
That would all depend upon the interconnect strategy, which hasn't reached
consensus either.
Based on the early module list, a bus probably isn't necessary, and
individual ribbon cable and/or coax will do if speeds stay low.
Sent: Wed, December 22, 2010 2:58:10 PM
Subject: Re: [time-nuts] Form factor
The use of i...@c that I proposed was ONLY for module-to-module
communication. I wrote that none of the internal chips in a module
were to be exposed to the i2c bus. A module may very well have it's
own internal bus
In message aanlktiklkd2z15kwbpewxtfgff=wqwsinv+to7oup...@mail.gmail.com, Chri
s Albertson writes:
Can CAN do this?
CANbus is mostly intented for hostile environments, and for anything
in-box less can do.
The problem with I2C is that it is not well suited for systems with
more than one master
On Wed, Dec 22, 2010 at 2:41 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message aanlktiklkd2z15kwbpewxtfgff=wqwsinv+to7oup...@mail.gmail.com,
Chri
s Albertson writes:
Can CAN do this?
CANbus is mostly intented for hostile environments, and for anything
in-box less can do.
The
El 22/12/2010 23:11, Chris Albertson escribió:
Again I don't care much what is used but I think we need
1) Reasonable speed
2) ALL cards should be peers with no master
3) in-band addressing
4) Small minimum size for the uP and low Flash memory footprint
Can CAN do this? I'm worried about #2
In message aanlktinsvco_px6npttfvrtjafy-wctgtfkxe6kee...@mail.gmail.com, Chri
s Albertson writes:
How hard is it to do multi-master I2C.
About as hard as multi-master MODBUS
I still like I2C because it
can be doe on the smallest of uP with zero extra hardware. But
something else might be
I think I'm missing the big picture. What sort of things are people
interested in building? Will they all be a reasonable fit with a single Form
Factor, Bus, and whatever?
I've been thinking of something like a mother board with FPGA that would fit
in something like the Hammond boxes. The
I think you have the idea, especially the part about needing only a
very few wires between the daughter boards. But if that is the case
why have a motherboard and what do you do with an FPGA?
So my idea is that daughter cards each go in a small aluminum box of
their own and connect between
On Wed, Dec 22, 2010 at 3:32 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
I used a shared opto-isolated async bus. You need two optocouplers
per microcontroller, and one place you power the shared bus, and
you're all set.
I have yet to see an microcontroller without an async port.
Perhaps I'm old school, but this sounds overly complex to me.
Probably the most important thing I learned in engineering school
(besides where the beer and amiable consorts were) was KISS. The more
complex, the less likely the project is to complete.
So I pose the question: Do we need a bus like
Comments inline. Hopefully I've edited this enough to prevent it being
overwhelming.
On Wed, Dec 22, 2010 at 7:40 PM, Hal Murray hmur...@megapathdsl.net wrote:
I think I'm missing the big picture. What sort of things are people
interested in building? Will they all be a reasonable fit with a
A modern counter is usually based around multichannel high resolution
time stamping.
To measure frequency one time stamps the output of a divider and
combines these results with the number of unknown frequency periods
between successive time stamps.
For example, one may divide down the
I don't see how a backplane bus with modules you plug in is simpler
then having only the modules with no backplane bus. The problem with
a hard backplane is that you have to know in advance what you are
going to plug into it. Another (seemingly unsolvable) problem is the
mechanical design. No
Time for me to jump in on the Form Factor...
How about something like this: http://www.blacet.com/
It's the smaller of the modular synths but Blacet can provide the racks and
a VERY quiet power supply (+/- 15V). The benefit to this is, the module can
be as wide as it needs to be... we can
Comms onthe text below: I would eliminate the moterboard completely
and incorporate it's function inside module that is built to the same form
factor as the modules that you have have plugged into the motherboard.
Big advantage is (1) mechanically much simpler and (2) yu can actually
change out
El 23/12/2010 05:24, Bob Bownes escribió:
ARM or other general purpose CPU is interesting, but at what cost for
complexity and/or software development? It would require RAM, IO
support, and boot rom at the very least. Not insurmountable, but at a
cost to complexity.
If you are not planifying
In message aanlkti=jwicdwbfwizorpuf3vpj=dzxxveq7cj-ab...@mail.gmail.com, Chri
s Albertson writes:
Opto-isolater? Why not just use fiber cable between cards.
I have only ever seen point-to-point versions, I needed 7 cards
connected.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
)
--
Message: 1
Date: Mon, 20 Dec 2010 22:29:47 -0800
From: Chris Albertson albertson.ch...@gmail.com
Subject: Re: [time-nuts] Form factor
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Cc: Open counter
Hi
One source of boxes to consider is old HP equipment, some is very
reasonably priced, like 37203 for small boxes and a 59401A makes an ideal
housing
for a Rb with clock GPS and backup power. Some times you can even use part
of the guts. I even went as far as repackaging my 5062C into a HP
I agree about the ebay finds. Bad to design the boards form factor around
old chassis.
Maybe the thing is to find out from the electronic design how big the
board(s) will have to be or what the electronic footprint is, then go from
there? If the boards are designed so that idiosyncratic mounting
Another factor to consider is that ps stability requires using coax
connectors that are mechanically stable to within a few microns ie no BNCs.
Bruce
Don Latham wrote:
I agree about the ebay finds. Bad to design the boards form factor around
old chassis.
Maybe the thing is to find out from
That would all depend upon the interconnect strategy, which hasn't reached
consensus either.
Based on the early module list, a bus probably isn't necessary, and individual
ribbon cable and/or coax will do if speeds stay low.
On Dec 21, 2010, at 2:34 PM, Bruce Griffiths
Hi all,
You might also consider these Hammond Like cabinets...
http://www.rfsupplier.com/index.php?cpath=103
I've used one for a project, very nice.
regards
Tim
--
VK2XTT :: QF56if :: BMARC :: WIA :: AMSAT-VK :: AMSAT
___
time-nuts mailing list
I wrote some more ideas, I'm trying here to write what might later,
after some edits become a consensous document. that captures what
most people want. Edit away, maybe some of this will make it to the
web site...
++
Here is an idea for the top of
Tom wrote:
Hammond boxes are great to work with and are reasonably inexpensive. You
can stack multiple boards inside, and panels are available in aluminum or
plastic. Hammond will make custom lengths, just for asking.
I'm still using similar extrusions left over from a project we did
years
Another (possibly bad) option is the old 22/44 pin .156 spacing card
bus. I don't know the official name of it, but there were many many
prototype cards and backplanes available for it in the day.
Yet another option would be to build these to fit in an existing
instrumentation chassis like the
Eurocard has been one suggestion as a form factor. While I personally
love Eurocard, the boards and connectors are expensive.
Stackble connectors are a pain in assembly.
Backplanes are inherently evil at high speeds.
Plugging everything into one main board makes that a critical design
I love those Hammond boxes until I have to pay the bill. The one for my n2pk
VNA was about $28.
But one of those as the primary enclosure with input boards and output boards
that plug into a main board would be feasable if a tad expensive.
Some modules lend themselves to plugins on a main
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