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Advice on Logic Analyzer

L

logicgeek

Jan 1, 1970
0
Hi

I'm considering to purchase a pc based logic analyzer. After a bit of
shopping around I narrowed down my options to either the Logicport
from Intronix or the Annie-USB from Janatek, maybe even their Logic-16
as well.

Before I make the final decision, is there anyone of you that owns any
of these instruments?
The obvious reason for the logicport is the fact that it costs only U
$389 for 32 channels and 500Mhz sampling rate. I have however read
this little faq article on janatek's website on how to
evaluate(compare) between various logic analyzers and I'm having
doubts of buying a logicport. The Annie-USB although a tad more
expensive seems to be a really good quality instrument. Any of you
having thoughts on this.

Luckily the need is not pressing so I have a couple of days.
 
V

Vladimir Vassilevsky

Jan 1, 1970
0
John said:
I've never used a logic analyzer. A dual-trace digital scope and a
little thinking is usually enough.

Strongly agree. "Little thinking" is the key part.
BTW, I've never had any use of ICE for the same reason.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
 
F

Frithiof Andreas Jensen

Jan 1, 1970
0
logicgeek said:
Hi

I'm considering to purchase a pc based logic analyzer. After a bit of
shopping around I narrowed down my options to either the Logicport
from Intronix or the Annie-USB from Janatek, maybe even their Logic-16
as well.

Before I make the final decision, is there anyone of you that owns any
of these instruments?

No.

Check if the trigger logic can be programmed for what you need - for example
if you are looking for memory corruption you want to trigger on access to
the corrupted location which will be a sequence of adress words.
 
R

Rich Webb

Jan 1, 1970
0
I've never used a logic analyzer. A dual-trace digital scope and a
little thinking is usually enough.

But hand-decoding an SPI data stream can get a little tiring. As the
saying goes: been there, done that, skipped a bit - had to start over.

The OP might also want to look at the Ant8 and Ant18 analyzers from
Rocky Logic http://www.rockylogic.com

That said, I've been using one of the Intronix LogicPorts for years.
Got it hooked up now watching a couple of CAN data streams, a 1 PPS
time mark, a UART's TX & RX, and a half-dozen discrete I/O pins. Their
latest firmware spin added the CAN interpreter to the existing SPI,
I2C, and async serial interpreters. Makes it very easy to check a
NMEA-to-CAN gateway.
 
S

Spehro Pefhany

Jan 1, 1970
0
But hand-decoding an SPI data stream can get a little tiring. As the
saying goes: been there, done that, skipped a bit - had to start over.

Scopes can do that these days, though some require extra $ to unlock
the feature in firmware.
The OP might also want to look at the Ant8 and Ant18 analyzers from
Rocky Logic http://www.rockylogic.com

That said, I've been using one of the Intronix LogicPorts for years.
Got it hooked up now watching a couple of CAN data streams, a 1 PPS
time mark, a UART's TX & RX, and a half-dozen discrete I/O pins. Their
latest firmware spin added the CAN interpreter to the existing SPI,
I2C, and async serial interpreters. Makes it very easy to check a
NMEA-to-CAN gateway.
Best regards,
Spehro Pefhany
 
N

Nico Coesel

Jan 1, 1970
0
logicgeek said:
Hi

I'm considering to purchase a pc based logic analyzer. After a bit of
shopping around I narrowed down my options to either the Logicport
from Intronix or the Annie-USB from Janatek, maybe even their Logic-16
as well.

Before I make the final decision, is there anyone of you that owns any
of these instruments?
The obvious reason for the logicport is the fact that it costs only U
$389 for 32 channels and 500Mhz sampling rate. I have however read
this little faq article on janatek's website on how to

I've used the logic port. It has way to little memory and it is not
very straightforward to use. If it where my money I would get the
janatek because it has 1mbit/channel memory.
 
Hi

I'm considering to purchase a pc based logic analyzer. After a bit of
shopping around I narrowed down my options to either the Logicport
from Intronix or the Annie-USB from Janatek, maybe even their Logic-16
as well.

Before I make the final decision, is there anyone of you that owns any
of these instruments?
The obvious reason for the logicport is the fact that it costs only U
$389 for 32 channels and 500Mhz sampling rate. I have however read
this little faq article on janatek's website on how to
evaluate(compare) between various logic analyzers and I'm having
doubts of buying a logicport. The Annie-USB although a tad more
expensive seems to be a really good quality instrument. Any of you
having thoughts on this.

Luckily the need is not pressing so I have a couple of days.

Most of these PC based instruments are very poor to start with, after
a few years they become unsupported and if you break them in the bin
they go. You would do much better looking on ebay for an Agilent or
Tek instrument for less money.
 
V

Vladimir Vassilevsky

Jan 1, 1970
0
John said:
On Mon, 14 Apr 2008 09:08:35 -0500, Vladimir Vassilevsky

I do use a hex background debugger (the PEMicro pod, for the 68332)
when testing embedded code. It lets me load code into RAM (which will
later be eprom), run it, step it, breakpoint, patch, snoop registers
and ram. It also lets me directly thrash hardware interfaces. A
combination of untested digital+analog hardware, untested FPGAs, and
4-12 kilobytes of untested uP code, running on a brand-new pc board,
exceeds *my* ability to just think it through.

I usually don't make many mistakes of the sort that can be helped by an
ICE. The ICE can be handy for troubleshooting of the minor technical
problems... but the best cure is not to create those problems at first time.

Initially, I develop the flashloader with the basic diagnostic facility
and the minimum hardware drivers for a new board. From there, the real
development starts. I can output whatever parameters I need through
whatever interface I have (Ethernet/CAN/RS232), without interferring
with the real time flow of the program and the states of cache and SDRAM.

I could never understand why some people need to look at the
SPI/I2C/UART/CAN lines when it is well known that the interface outputs
exactly what you are writing into it and exactly in the way you
configured it. The upper level protocol progress is better seen from the
inside of the machine rather then by observing the lines.
The bdm pod plugs into a little 10-pin header that we include on all
of our embedded products.

I have to include the 14-pin JTAG connector, too, because some other
developers just can't live without it :)


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
 
There was a separate thread where he was discussing various ways of
interfacing to the PCI bus and doing anything from rolling your own interface
from scratch to using the simple/free PCI interfaces inside an FPGA to using a
full-fledged interface (still in an FPGA) to using the, e.g., PLX interface
ICs that do it all for you... hence I was just making the point that someone
who did choose to go the "roll your own" route would probably end up using a
logic analyzer, sooner or later, even though realistically I doubt John is
going to go that route and agree with you that, these days, very few people
could make a good case for doing so anyway.

OK, just curious. I'm a bit naive; how does a logic analyzer handle
the reflected wave switching thingy of PCI signals? Can it interpret
the levels correctly?
 
I've used the logic port. It has way to little memory and it is not
very straightforward to use. If it where my money I would get the
janatek because it has 1mbit/channel memory.

I've experienced that too. It is a nice simple analyzer but if you
want to do something a bit weird like sample an entire screenful of
TTL RGBI (old video standard on 8 bit computers) data it cannot do
this. With 2048 bytes per channel it can barely store one or two lines
even with compression. It just doesn't work for this application. It
does work great for looking at an entire scanline with state data from
the rest of the computer. But I needed the whole screen full. Oh well,
it's a good thing I stopped that project... :)
 
D

David L. Jones

Jan 1, 1970
0
I've experienced that too. It is a nice simple analyzer but if you
want to do something a bit weird like sample an entire screenful of
TTL RGBI (old video standard on 8 bit computers) data it cannot do
this. With 2048 bytes per channel it can barely store one or two lines
even with compression. It just doesn't work for this application. It
does work great for looking at an entire scanline with state data from
the rest of the computer. But I needed the whole screen full. Oh well,
it's a good thing I stopped that project... :)

Does the LogicPort use transitional sampling?
It appears to with a spec that that includes "compression":
"Maximum sample compression: 2^33 to 1 (sample rates to 200MHz)"

If that is the case then the 2048 sample memory isn't as limiting as a
normal time sampling 2048 sample logic analyser. But I'd go for the
bigger memory unit myself.

Dave.
 
R

Rich Webb

Jan 1, 1970
0
I could never understand why some people need to look at the
SPI/I2C/UART/CAN lines when it is well known that the interface outputs
exactly what you are writing into it and exactly in the way you
configured it. The upper level protocol progress is better seen from the
inside of the machine rather then by observing the lines.

It can be a real help when, e.g., bringing up CAN on a new (to me)
microcontroller family for the first time. CAN peripherals have
wonderful "smarts" but getting there means a different register set
for every manufacturer.
 
R

Rich Webb

Jan 1, 1970
0
Does the LogicPort use transitional sampling?
Yes.

It appears to with a spec that that includes "compression":
"Maximum sample compression: 2^33 to 1 (sample rates to 200MHz)"

If that is the case then the 2048 sample memory isn't as limiting as a
normal time sampling 2048 sample logic analyser. But I'd go for the
bigger memory unit myself.

It's not a universal tool, as evidenced by the "entire screenful"
example above, but I've been really happy with mine. I've also used
deep-memory realtime, non-transition analyzers and prefer the
LogicPort. A 1 Mbit/channel buffer at even a relatively slow 10 Msps
fills up in only 100 msec.

I am surprised, though, that Intronix hasn't come out with a follow-on
product with more sample memory. The LogicPort has been out for quite
a while (as these things go).
 
L

logicgeek

Jan 1, 1970
0
It's not a universal tool, as evidenced by the "entire screenful"
example above, but I've been really happy with mine. I've also used
deep-memory realtime, non-transition analyzers and prefer the
LogicPort. A 1 Mbit/channel buffer at even a relatively slow 10 Msps
fills up in only 100 msec.

I am surprised, though, that Intronix hasn't come out with a follow-on
product with more sample memory. The LogicPort has been out for quite
a while (as these things go).

Interesting to had seen what jumped out in this conversation, all the
finer nuances :) Bob was right, times are changing

It seems that Janatek, the company that manufactures the Annie-USB and
Logic-16 has been around for some time. What I also like about the
Annie-USB is that it is also a pattern generator. These things cost
some money if you buy it separate. Anyway I came across an article on
their website that eloborate on which aspects you should consider when
comparing pc based logic analyzers. http://www.janatek.com/faq_buying_logic_analyzer.html

The rocky's also seems to me worth considering
 
Interesting to had seen what jumped out in this conversation, all the
finer nuances :) Bob was right, times are changing

It seems that Janatek, the company that manufactures the Annie-USB and
Logic-16 has been around for some time. What I also like about the
Annie-USB is that it is also a pattern generator. These things cost
some money if you buy it separate. Anyway I came across an article on
their website that eloborate on which aspects you should consider when
comparing pc based logic analyzers. http://www.janatek.com/faq_buying_logic_analyzer.html

The rocky's also seems to me worth considering

Well to be fair, nobody's usually dumb enough to want to sample an
entire screen full of RGBI data, usually you just use a RGBI monitor
for that!
Looking at one line is usually enough. Except when you interlace the
display, and the physically "next" line on the screen is an entire
vsync time away. Of course you could program the triggers to ignore
the rest of the field but now I don't remember if you could do that
with the Logicport.

You know, it is spring cleaning time here in the northern hemisphere.
Maybe I'll put my logicport up for sale, since I haven't used it in a
year and that's an important criteria in the cleaning.
 
It's faster and cheaper to analyze your logic before you build it.

John

But what if you're analyzing someone else's design from twenty years
ago and there's no documentation?
Sometimes a new design has to work with old stuff.
I wonder if there's a logic analyzer with enough input range to handle
the logic levels inside a 6R1A?
 
N

Nico Coesel

Jan 1, 1970
0
Well to be fair, nobody's usually dumb enough to want to sample an
entire screen full of RGBI data, usually you just use a RGBI monitor
for that!

That depends on what you want to do with your data. I don't know about
the Janatek LA, but my own LA (a tektronix DAS9200) allows to read the
acquisition memory into the PC for automated analysis or drawing
pretty pictures on the screen based on the data.
 
S

stevepierson

Jan 1, 1970
0
On Apr 15, 9:52 am, John Larkin
It's faster and cheaper to analyze your logic before you build it.

That's small company talk for sure!

A large company has vastly different day to day problems that what you
normally experience.
 
N

Nico Coesel

Jan 1, 1970
0
John Larkin said:
It's faster and cheaper to analyze your logic before you build it.

Statements like these make me wonder if I should give Modelsim a
try... Still, the thought of having to create a testbench doesn't
appeal to me. Especially for a design that has a massive amount of
configuration registers. Anyway, it all boils down to verifying your
design one way or another.
 
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