Logic analyzers...

[Phil Hobbs]

We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[LM]

16 channels USB
https://www.dreamsourcelab.com/product/dslogic-series/

On Tue, 10 Jan 2023 17:12:36 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?

Thanks

Phil Hobbs

 

[LM]

16 channels USB
https://www.dreamsourcelab.com/product/dslogic-series/

On Tue, 10 Jan 2023 17:12:36 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?

Thanks

Phil Hobbs

 

[LM]

16 channels USB
https://www.dreamsourcelab.com/product/dslogic-series/

On Tue, 10 Jan 2023 17:12:36 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?

Thanks

Phil Hobbs

 

[Lasse Langwadt Christensen]

onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:

On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.

it streams input data directly to the PC, there is no buffer

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.

that\'s not how USB works

 

[Lasse Langwadt Christensen]

onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:

On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.

it streams input data directly to the PC, there is no buffer

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.

that\'s not how USB works

 

[Lasse Langwadt Christensen]

onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:

On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.

it streams input data directly to the PC, there is no buffer

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.

that\'s not how USB works

 

[Lasse Langwadt Christensen]

torsdag den 12. januar 2023 kl. 18.45.50 UTC+1 skrev Phil Hobbs:

Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 21.26.12 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 03.02.11 UTC+1 skrev jjhu...@gmail.com:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?


If you are drawn to PC-USB configurations, I\'ve used the Saleae Pro 16 and thought it was pretty good - a bit higher in price than some of the chinesium products.

\"a bit\", about 100x ...

The Chinesium ones use a Nordic 8-bit-parallel-to-USB3 chip, and the
rest is up to Sigrok.

Turns out that you can get 16 bits by using two of them at once. You
have to stitch the decoded data files together yourself, but that\'s not
too hard. (Simon\'s a Python whiz.)

Our setup is:

Dongle 0 ($5, AliExpress) : bit 0 = clock, bits 1-7 = ADC bits 0-6

Dongle 1 ($8, Amazon) : bit 0 = clock, bits 0-8 = ADC bits 6-13

They\'re both looking at the clock and at bit 6, so it\'s easy to align
the time stamps.

The ADC clock is coming from a Highland P400 DDG, so we just wired it
up, hit the green button to start the clock, and it just works. (BTW
the Ali one has the label on straight, and the Amazon one doesn\'t.)


I have a few, some are just bare boards (probably intended as USB dev board and I think it can do 16bits )

all based on a Cypress FX2 chip which basically a 8051 with high speed USB

Well, we\'re going to be in the market for a real 16-bit one, it looks
like. Turns out that this 12-bit ADC has a _gigantic_ glitch at the bit
10 carry--see

boards like this will do 16bit with sigrok/pulseview
https://www.amazon.com/Cypress-CY7C68013A-EZ-USB-USB2-0-Development/dp/B06XHP9XKF

but of course with the same USB bandwidth limitations

https://electrooptical.net/www/sed/Glitch.png> and
https://electrooptical.net/www/sed/GlitchDetail.png>.

These are single frames from a cell phone video summary, so they aren\'t
perfect, but they get the point across.

The red curve is the ADC samples, plotted against the right hand scale,
and the blue curve is the input ramp signal, plotted against the left
hand scale in volts. The horizontal scale is seconds. The two curves
were roughly aligned by eye, which accounts for the minor time scale
error. The ADC clock was 1 MHz, and the logic analyzer\'s was 16 MHz
(give or take).

that looks weird, that \"exponential decay\" is actual samples and not some artifact of the plotting?

 

[Lasse Langwadt Christensen]

torsdag den 12. januar 2023 kl. 18.45.50 UTC+1 skrev Phil Hobbs:

Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 21.26.12 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 03.02.11 UTC+1 skrev jjhu...@gmail.com:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?


If you are drawn to PC-USB configurations, I\'ve used the Saleae Pro 16 and thought it was pretty good - a bit higher in price than some of the chinesium products.

\"a bit\", about 100x ...

The Chinesium ones use a Nordic 8-bit-parallel-to-USB3 chip, and the
rest is up to Sigrok.

Turns out that you can get 16 bits by using two of them at once. You
have to stitch the decoded data files together yourself, but that\'s not
too hard. (Simon\'s a Python whiz.)

Our setup is:

Dongle 0 ($5, AliExpress) : bit 0 = clock, bits 1-7 = ADC bits 0-6

Dongle 1 ($8, Amazon) : bit 0 = clock, bits 0-8 = ADC bits 6-13

They\'re both looking at the clock and at bit 6, so it\'s easy to align
the time stamps.

The ADC clock is coming from a Highland P400 DDG, so we just wired it
up, hit the green button to start the clock, and it just works. (BTW
the Ali one has the label on straight, and the Amazon one doesn\'t.)


I have a few, some are just bare boards (probably intended as USB dev board and I think it can do 16bits )

all based on a Cypress FX2 chip which basically a 8051 with high speed USB

Well, we\'re going to be in the market for a real 16-bit one, it looks
like. Turns out that this 12-bit ADC has a _gigantic_ glitch at the bit
10 carry--see

boards like this will do 16bit with sigrok/pulseview
https://www.amazon.com/Cypress-CY7C68013A-EZ-USB-USB2-0-Development/dp/B06XHP9XKF

but of course with the same USB bandwidth limitations

https://electrooptical.net/www/sed/Glitch.png> and
https://electrooptical.net/www/sed/GlitchDetail.png>.

These are single frames from a cell phone video summary, so they aren\'t
perfect, but they get the point across.

The red curve is the ADC samples, plotted against the right hand scale,
and the blue curve is the input ramp signal, plotted against the left
hand scale in volts. The horizontal scale is seconds. The two curves
were roughly aligned by eye, which accounts for the minor time scale
error. The ADC clock was 1 MHz, and the logic analyzer\'s was 16 MHz
(give or take).

that looks weird, that \"exponential decay\" is actual samples and not some artifact of the plotting?

 

[Lasse Langwadt Christensen]

torsdag den 12. januar 2023 kl. 18.45.50 UTC+1 skrev Phil Hobbs:

Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 21.26.12 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 03.02.11 UTC+1 skrev jjhu...@gmail.com:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?


If you are drawn to PC-USB configurations, I\'ve used the Saleae Pro 16 and thought it was pretty good - a bit higher in price than some of the chinesium products.

\"a bit\", about 100x ...

The Chinesium ones use a Nordic 8-bit-parallel-to-USB3 chip, and the
rest is up to Sigrok.

Turns out that you can get 16 bits by using two of them at once. You
have to stitch the decoded data files together yourself, but that\'s not
too hard. (Simon\'s a Python whiz.)

Our setup is:

Dongle 0 ($5, AliExpress) : bit 0 = clock, bits 1-7 = ADC bits 0-6

Dongle 1 ($8, Amazon) : bit 0 = clock, bits 0-8 = ADC bits 6-13

They\'re both looking at the clock and at bit 6, so it\'s easy to align
the time stamps.

The ADC clock is coming from a Highland P400 DDG, so we just wired it
up, hit the green button to start the clock, and it just works. (BTW
the Ali one has the label on straight, and the Amazon one doesn\'t.)


I have a few, some are just bare boards (probably intended as USB dev board and I think it can do 16bits )

all based on a Cypress FX2 chip which basically a 8051 with high speed USB

Well, we\'re going to be in the market for a real 16-bit one, it looks
like. Turns out that this 12-bit ADC has a _gigantic_ glitch at the bit
10 carry--see

boards like this will do 16bit with sigrok/pulseview
https://www.amazon.com/Cypress-CY7C68013A-EZ-USB-USB2-0-Development/dp/B06XHP9XKF

but of course with the same USB bandwidth limitations

https://electrooptical.net/www/sed/Glitch.png> and
https://electrooptical.net/www/sed/GlitchDetail.png>.

These are single frames from a cell phone video summary, so they aren\'t
perfect, but they get the point across.

The red curve is the ADC samples, plotted against the right hand scale,
and the blue curve is the input ramp signal, plotted against the left
hand scale in volts. The horizontal scale is seconds. The two curves
were roughly aligned by eye, which accounts for the minor time scale
error. The ADC clock was 1 MHz, and the logic analyzer\'s was 16 MHz
(give or take).

that looks weird, that \"exponential decay\" is actual samples and not some artifact of the plotting?

 

[Fred Bloggs]

On Wednesday, January 11, 2023 at 9:20:35 AM UTC-5, lang...@fonz.dk wrote:

onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.
it streams input data directly to the PC, there is no buffer

Then what is that sample memory depth about in the spec sheet?

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.
that\'s not how USB works

That\'s how a USB stick works, and this analyzer says it has a USB output. Sounds like a match to me.

 

[Fred Bloggs]

On Wednesday, January 11, 2023 at 9:20:35 AM UTC-5, lang...@fonz.dk wrote:

onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.
it streams input data directly to the PC, there is no buffer

Then what is that sample memory depth about in the spec sheet?

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.
that\'s not how USB works

That\'s how a USB stick works, and this analyzer says it has a USB output. Sounds like a match to me.

 

[Fred Bloggs]

On Wednesday, January 11, 2023 at 9:20:35 AM UTC-5, lang...@fonz.dk wrote:

onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.
it streams input data directly to the PC, there is no buffer

Then what is that sample memory depth about in the spec sheet?

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.
that\'s not how USB works

That\'s how a USB stick works, and this analyzer says it has a USB output. Sounds like a match to me.

 

[Phil Hobbs]

Lasse Langwadt Christensen wrote:

torsdag den 12. januar 2023 kl. 18.45.50 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 21.26.12 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 03.02.11 UTC+1 skrev
jjhu...@gmail.com:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil
Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic
analyzer--a Chinese knockoff of a Saleae Logic 8. It\'s
been pretty handy for characterizing the ADC in a
bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher
sample rates it quits after ~100k samples. Sheesh, and we
spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of
instrument you want to pull out and attach down in the
guts of some gizmo, and with USB you can just use a
longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than
our $8 Chinesium knockoff. Suggestions?


If you are drawn to PC-USB configurations, I\'ve used the
Saleae Pro 16 and thought it was pretty good - a bit higher
in price than some of the chinesium products.

\"a bit\", about 100x ...

The Chinesium ones use a Nordic 8-bit-parallel-to-USB3 chip,
and the rest is up to Sigrok.

Turns out that you can get 16 bits by using two of them at
once. You have to stitch the decoded data files together
yourself, but that\'s not too hard. (Simon\'s a Python whiz.)

Our setup is:

Dongle 0 ($5, AliExpress) : bit 0 = clock, bits 1-7 = ADC bits
0-6

Dongle 1 ($8, Amazon) : bit 0 = clock, bits 0-8 = ADC bits
6-13

They\'re both looking at the clock and at bit 6, so it\'s easy to
align the time stamps.

The ADC clock is coming from a Highland P400 DDG, so we just
wired it up, hit the green button to start the clock, and it
just works. (BTW the Ali one has the label on straight, and the
Amazon one doesn\'t.)


I have a few, some are just bare boards (probably intended as USB
dev board and I think it can do 16bits )

all based on a Cypress FX2 chip which basically a 8051 with high
speed USB

Well, we\'re going to be in the market for a real 16-bit one, it
looks like. Turns out that this 12-bit ADC has a _gigantic_ glitch
at the bit 10 carry--see

boards like this will do 16bit with sigrok/pulseview
https://www.amazon.com/Cypress-CY7C68013A-EZ-USB-USB2-0-Development/dp/B06XHP9XKF

but of course with the same USB bandwidth limitations

Interesting, thanks.

https://electrooptical.net/www/sed/Glitch.png> and
https://electrooptical.net/www/sed/GlitchDetail.png>.

These are single frames from a cell phone video summary, so they
aren\'t perfect, but they get the point across.

The red curve is the ADC samples, plotted against the right hand
scale, and the blue curve is the input ramp signal, plotted against
the left hand scale in volts. The horizontal scale is seconds. The
two curves were roughly aligned by eye, which accounts for the
minor time scale error. The ADC clock was 1 MHz, and the logic
analyzer\'s was 16 MHz (give or take).

that looks weird, that \"exponential decay\" is actual samples and not
some artifact of the plotting?

Sure looks real to us. It\'s a pipelined capacitive ADC, so internal
settling stuff can come out in subsequent samples.

I don\'t know enough about the design to comment much on its guts.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

Lasse Langwadt Christensen wrote:

torsdag den 12. januar 2023 kl. 18.45.50 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 21.26.12 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 03.02.11 UTC+1 skrev
jjhu...@gmail.com:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil
Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic
analyzer--a Chinese knockoff of a Saleae Logic 8. It\'s
been pretty handy for characterizing the ADC in a
bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher
sample rates it quits after ~100k samples. Sheesh, and we
spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of
instrument you want to pull out and attach down in the
guts of some gizmo, and with USB you can just use a
longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than
our $8 Chinesium knockoff. Suggestions?


If you are drawn to PC-USB configurations, I\'ve used the
Saleae Pro 16 and thought it was pretty good - a bit higher
in price than some of the chinesium products.

\"a bit\", about 100x ...

The Chinesium ones use a Nordic 8-bit-parallel-to-USB3 chip,
and the rest is up to Sigrok.

Turns out that you can get 16 bits by using two of them at
once. You have to stitch the decoded data files together
yourself, but that\'s not too hard. (Simon\'s a Python whiz.)

Our setup is:

Dongle 0 ($5, AliExpress) : bit 0 = clock, bits 1-7 = ADC bits
0-6

Dongle 1 ($8, Amazon) : bit 0 = clock, bits 0-8 = ADC bits
6-13

They\'re both looking at the clock and at bit 6, so it\'s easy to
align the time stamps.

The ADC clock is coming from a Highland P400 DDG, so we just
wired it up, hit the green button to start the clock, and it
just works. (BTW the Ali one has the label on straight, and the
Amazon one doesn\'t.)


I have a few, some are just bare boards (probably intended as USB
dev board and I think it can do 16bits )

all based on a Cypress FX2 chip which basically a 8051 with high
speed USB

Well, we\'re going to be in the market for a real 16-bit one, it
looks like. Turns out that this 12-bit ADC has a _gigantic_ glitch
at the bit 10 carry--see

boards like this will do 16bit with sigrok/pulseview
https://www.amazon.com/Cypress-CY7C68013A-EZ-USB-USB2-0-Development/dp/B06XHP9XKF

but of course with the same USB bandwidth limitations

Interesting, thanks.

https://electrooptical.net/www/sed/Glitch.png> and
https://electrooptical.net/www/sed/GlitchDetail.png>.

These are single frames from a cell phone video summary, so they
aren\'t perfect, but they get the point across.

The red curve is the ADC samples, plotted against the right hand
scale, and the blue curve is the input ramp signal, plotted against
the left hand scale in volts. The horizontal scale is seconds. The
two curves were roughly aligned by eye, which accounts for the
minor time scale error. The ADC clock was 1 MHz, and the logic
analyzer\'s was 16 MHz (give or take).

that looks weird, that \"exponential decay\" is actual samples and not
some artifact of the plotting?

Sure looks real to us. It\'s a pipelined capacitive ADC, so internal
settling stuff can come out in subsequent samples.

I don\'t know enough about the design to comment much on its guts.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

Lasse Langwadt Christensen wrote:

torsdag den 12. januar 2023 kl. 18.45.50 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 21.26.12 UTC+1 skrev Phil Hobbs:
Lasse Langwadt Christensen wrote:
onsdag den 11. januar 2023 kl. 03.02.11 UTC+1 skrev
jjhu...@gmail.com:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil
Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic
analyzer--a Chinese knockoff of a Saleae Logic 8. It\'s
been pretty handy for characterizing the ADC in a
bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher
sample rates it quits after ~100k samples. Sheesh, and we
spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of
instrument you want to pull out and attach down in the
guts of some gizmo, and with USB you can just use a
longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than
our $8 Chinesium knockoff. Suggestions?


If you are drawn to PC-USB configurations, I\'ve used the
Saleae Pro 16 and thought it was pretty good - a bit higher
in price than some of the chinesium products.

\"a bit\", about 100x ...

The Chinesium ones use a Nordic 8-bit-parallel-to-USB3 chip,
and the rest is up to Sigrok.

Turns out that you can get 16 bits by using two of them at
once. You have to stitch the decoded data files together
yourself, but that\'s not too hard. (Simon\'s a Python whiz.)

Our setup is:

Dongle 0 ($5, AliExpress) : bit 0 = clock, bits 1-7 = ADC bits
0-6

Dongle 1 ($8, Amazon) : bit 0 = clock, bits 0-8 = ADC bits
6-13

They\'re both looking at the clock and at bit 6, so it\'s easy to
align the time stamps.

The ADC clock is coming from a Highland P400 DDG, so we just
wired it up, hit the green button to start the clock, and it
just works. (BTW the Ali one has the label on straight, and the
Amazon one doesn\'t.)


I have a few, some are just bare boards (probably intended as USB
dev board and I think it can do 16bits )

all based on a Cypress FX2 chip which basically a 8051 with high
speed USB

Well, we\'re going to be in the market for a real 16-bit one, it
looks like. Turns out that this 12-bit ADC has a _gigantic_ glitch
at the bit 10 carry--see

boards like this will do 16bit with sigrok/pulseview
https://www.amazon.com/Cypress-CY7C68013A-EZ-USB-USB2-0-Development/dp/B06XHP9XKF

but of course with the same USB bandwidth limitations

Interesting, thanks.

https://electrooptical.net/www/sed/Glitch.png> and
https://electrooptical.net/www/sed/GlitchDetail.png>.

These are single frames from a cell phone video summary, so they
aren\'t perfect, but they get the point across.

The red curve is the ADC samples, plotted against the right hand
scale, and the blue curve is the input ramp signal, plotted against
the left hand scale in volts. The horizontal scale is seconds. The
two curves were roughly aligned by eye, which accounts for the
minor time scale error. The ADC clock was 1 MHz, and the logic
analyzer\'s was 16 MHz (give or take).

that looks weird, that \"exponential decay\" is actual samples and not
some artifact of the plotting?

Sure looks real to us. It\'s a pipelined capacitive ADC, so internal
settling stuff can come out in subsequent samples.

I don\'t know enough about the design to comment much on its guts.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Lasse Langwadt Christensen]

onsdag den 11. januar 2023 kl. 15.25.55 UTC+1 skrev Fred Bloggs:

On Wednesday, January 11, 2023 at 9:20:35 AM UTC-5, lang...@fonz.dk wrote:
onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.
it streams input data directly to the PC, there is no buffer
Then what is that sample memory depth about in the spec sheet?

they have to write something, they could have written unlimited except by resources on PC

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.
that\'s not how USB works
That\'s how a USB stick works, and this analyzer says it has a USB output. Sounds like a match to me.

no, that is not how USB works

 

[Lasse Langwadt Christensen]

onsdag den 11. januar 2023 kl. 15.25.55 UTC+1 skrev Fred Bloggs:

On Wednesday, January 11, 2023 at 9:20:35 AM UTC-5, lang...@fonz.dk wrote:
onsdag den 11. januar 2023 kl. 15.01.44 UTC+1 skrev Fred Bloggs:
On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:
We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.
Looks like that thing has a mind of its own with lots of interplay between available internal resources and your acquisition settings. I don\'t like the sound of that loop buffer for the sample data where it sounds like it just writes over old data without even telling you. Then the spec says it has a \"10+ billion\" ( somethings they don\'t say) sample memory depth, which leads you to believe they can buffer a significant amount of sample time, but then it goes on to say your computer is the buffer memory.
it streams input data directly to the PC, there is no buffer
Then what is that sample memory depth about in the spec sheet?

they have to write something, they could have written unlimited except by resources on PC

All logic analyzer designs are illogical.

Maybe look for a fast USB disc you can plug directly into the Saleae to take in the stream, and read that out later.
that\'s not how USB works
That\'s how a USB stick works, and this analyzer says it has a USB output. Sounds like a match to me.

no, that is not how USB works

 

[Three Jeeps]

On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:

We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Up front note: I am a believer in high end logic analyzers after I was part of a team to evaluate (at HP\'s request) their two products (1602A, 1610 a )logic analyzers back in the day. Fast fwd to 2023....
Without knowing some of your requirements (speed, channels, etc.) hard to say. Still, I\'d point you to Keysight 16861A - a 34 channel LA or the 16862a (currently have one in my lab). May not be in the budget you have. I\'d consider a older used unit.

If you are drawn to PC-USB configurations, I\'ve used the Saleae Pro 16 and thought it was pretty good - a bit higher in price than some of the chinesium products. Fairly good sampling rates: 500 MS/s and 100 MHz for digital, and analog of 50 MS/s and 5 MHz.

I have seen but not used a Digilent product, which intrigues me:
Digilent Digital (or Analog) discovery.
https://digilent.com/shop/digital-discovery-portable-usb-logic-analyzer-and-digital-pattern-generator/
https://digilent.com/search.php?search_query_adv=%22discovery%22

A colleague of mine recently got this for his lab, which he likes (after doing a fair bit of searching). It may be more functionality than you need but the DA +LA functions are intriguing...
https://www.dreamsourcelab.com
In general, I am not a big fan of having test gear tied to a PC ....You are tied into continuous vendor support to keep up with OS updates and changes, unless one freezes their environment.

Good luck

 

[Three Jeeps]

On Tuesday, January 10, 2023 at 5:12:50 PM UTC-5, Phil Hobbs wrote:

We\'ve been using a little 8-bit, 48-MHz USB logic analyzer--a Chinese
knockoff of a Saleae Logic 8. It\'s been pretty handy for characterizing
the ADC in a bathymetric lidar chip we\'ve been helping design.

It\'ll stream data forever at 16 MS/s. However, at higher sample rates
it quits after ~100k samples. Sheesh, and we spent eight bucks on it.

The USB form factor is nice, because it\'s the sort of instrument you
want to pull out and attach down in the guts of some gizmo, and with USB
you can just use a longer cable, which is convenient.

Sooo, I\'m considering buying something a bit better than our $8
Chinesium knockoff. Suggestions?

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Up front note: I am a believer in high end logic analyzers after I was part of a team to evaluate (at HP\'s request) their two products (1602A, 1610 a )logic analyzers back in the day. Fast fwd to 2023....
Without knowing some of your requirements (speed, channels, etc.) hard to say. Still, I\'d point you to Keysight 16861A - a 34 channel LA or the 16862a (currently have one in my lab). May not be in the budget you have. I\'d consider a older used unit.

If you are drawn to PC-USB configurations, I\'ve used the Saleae Pro 16 and thought it was pretty good - a bit higher in price than some of the chinesium products. Fairly good sampling rates: 500 MS/s and 100 MHz for digital, and analog of 50 MS/s and 5 MHz.

I have seen but not used a Digilent product, which intrigues me:
Digilent Digital (or Analog) discovery.
https://digilent.com/shop/digital-discovery-portable-usb-logic-analyzer-and-digital-pattern-generator/
https://digilent.com/search.php?search_query_adv=%22discovery%22

A colleague of mine recently got this for his lab, which he likes (after doing a fair bit of searching). It may be more functionality than you need but the DA +LA functions are intriguing...
https://www.dreamsourcelab.com
In general, I am not a big fan of having test gear tied to a PC ....You are tied into continuous vendor support to keep up with OS updates and changes, unless one freezes their environment.

Good luck