EEVblog #661 - Mailbag

[Rasz]

JAVA backend!! this is pretty retarded
"capative tuner" in pdf doesnt look promising either
yeeep, whole fpga firmware was drag&dropped in some Altera wizard
software has ac/dc coupling switch, diagram shows hardwired DC coupling
whole thing was designed by nck research (two ethernet guys - thats what they say about themselves)
its rev 1
at least python UI comes with source code

AD logo on PCB at least suggests a possibility AnalogDevices had some decency and made one of their grey beards look at the design and maybe even tune the front end so its not pure shit, but im probably dreaming screenshot shows 2.5MHz square wave and it looks passable


found software link
http://www.arrownac.com/solutions/bescope/downloads/BeScope_Installation_package_8-7-14.zip

$50 made me want to buy it, but shipping is pretty lol, I refuse to pay $40 for shipping, F that


aaand good read here:
http://forums.parallax.com/showthread.php/157115-BeScopeBundle-System-Files

broken software, shipped not programmed, idiots responding to support mails. Sounds just as good as any chinese USB scope

[FrankBuss]

aaand good read here:
http://forums.parallax.com/showthread.php/157115-BeScopeBundle-System-Files

broken software, shipped not programmed, idiots responding to support mails. Sounds just as good as any chinese USB scope

YYMD. He is probably right how the software was developed. A FTDI chip, which sends samples in ASCII to a TCL script, which sends it to a Python script, which provides a TCP/IP interface and then a Java program which displays it!?

[miguelvp]

I did order one anyways.

I guess what I'm getting from that thread is to only use the code as a reference guide and roll my own. What I'm I getting into? 

[miguelvp]

By looking at what comes with the kit I noticed this,

Kit Includes for $50 the following:

BeMicro CV Eval Kit $49
SDP Interposer $50
mini USB cable $whocares
oscilloscope probe $10 (cheap 150MHz probe at best)
BeScope Daughter Card $45

Just the InterPoser goes for $50 and opens me up for the first part of these (the SDP connector ones):
http://wiki.analog.com/resources/alliances/altera

Also looking at the docs, the ADC can be configured to a single channel 500MSPS instead of the dual channel 250MSPS each.

The code is a mess but at least they do seem to have a full QSys system without NIOS, not confirmed but I will look at it later.
Also there are some free lvds (at least 4 pair channels) left and one I2C (2 pins) also not connected. The InterPoser offers extra pins not used by the other headers, for what I read in the forum is 60 more available via the InterPoser SDP connector.

[Rasz]

Also there are some free lvds (at least 4 pair channels) left and one I2C (2 pins) also not connected. The InterPoser offers extra pins not used by the other headers, for what I read in the forum is 60 more available via the InterPoser SDP connector.

I think someone on parallax forum said bescope pcb has all unused IO grounded

[miguelvp]

The doc shows them as N/C so I hope they are not connected at all, if they are (connected to ground), well there are an extra 60 pin on the edge connector, will have to look into the FPGAs datasheet to see if they can do LVDS (the BeMicro docs don't show much detail on those other than 2.5V and 3.3V capable), otherwise I have a video 3 channel dac that I could use to drive an SVGA signal.

Edit: but since the edge connector interfaces with other analog devices dev boards they must have some lvds signals lying around.

[miguelvp]

The BeScope showed up today and it's almost time to leave work and go play with it

Thanks to the work of the user thoth at the parallax propeller forum I should be able to get it running in no time.
Ill see how well it does with a composite signal if I'm successful at getting it running.

Then I'll see how much an ADI module from Analog devices are to make an ARB or DDS since now I have the SDP Interposer and an spare BeMicro CV.

Oh, and BeMicro is coming with a CV-A9 version with a beefier Cyclone V if it doesn't get cancelled.

[miguelvp]

So I got it all setup and no errors anywhere but I get no test signal (measured with my rigol to make sure) and it doesn't display a thing. I did use my existing board and made sure the VCCIO jumper is set to 3.3V, so I guess the next thing is to supply the extra 5V with the microUSB connector on the ADC board.

Or maybe I'll use the supplied board but it looks like it's the same thing.

BTW I did test all the N/C pins and they are not grounded nor connected to anything. Not even the Device and Pin Options has them set as grounded, the project has the unused pins set to as input tri-stated.

The probe it came with it is a 100MHz probe, they look like the UNI-T probes I got from mortoncontrols but 100MHz instead of 300MHz.
https://www.mortoncontrols.com/index.php/clearance/utp06.html

It does feel cheaper material wise but not terrible, but they go on ebay for under $10 (model P6100)

[miguelvp]

What do you know, it only needed the 5V supply to the ADC board. Edit: seems like the half amp my PC can supply is not enough to power both the BeMicro and the BeScope, probably with a powered hub it might work without powering both boards.

Not much I can do with it yet because the software is very limited to adjust to longer time periods but it's a pretty good base to start with.

By the way, it gets pretty warm!

Pictures of the device generating 2.5MHz and 5.0MHz ringing square waves as well what the DS2202 sees.

2.5MHz:


5.0MHz:


Rigol:




The last two attachments are the full res captures, the ones in here where resized to be 800 pixels wide instead of 1324 pixels wide.

Edit: Not bad at all for just $50, the thing I'm more exited about is the SDP Interposer so I can connect to other Analog Devices boards.

http://wiki.analog.com/resources/alliances/altera

Also the connector Analog Devices uses is a Hirose FX8-120S-SV that mates with the FX8-120P-SV in the Interposer, they are fairly cheap.

Edit: BTW the reference clock comes from an SIT8033AC-31-25A-5.00000 2-Frequency Select Oscillator in this case it's a 5MHz divisible by two with by driving the FS pin. Looks very precise (the clock not the BeScope).
http://www.sitime.com/products/datasheets/sit8033/SiT8033-datasheet.pdf

I can't find any in stock but I've seen other frequencies/dividers available.

I wonder if the output can be cleaned up, the output clock is pulled down by a 1K 1/8W 1% resistor.

[tjringsmose]

About that SMD dev board.
I know that the pin pitch array is a common technique, but I can't shake the feeling that a chip with a ground pad, is wound to short some pins, especially on the larger packages. Do you scrape off the solder pads or is it a non-issue?

[rs20]

About that SMD dev board.
I know that the pin pitch array is a common technique, but I can't shake the feeling that a chip with a ground pad, is wound to short some pins, especially on the larger packages. Do you scrape off the solder pads or is it a non-issue?

Most such packages don't have a ground pad. I think if they do have a ground pad, you want a specific adapter board, rather than a one-size-fits-all -- if only because the thermal dissipation just isn't there.

[simingx]

Oh hey, I see my package there (large Singapore Post box)
Nice to know it showed up after 1 month in transit (I think Dave will like it, it's a piece of retro HP gear

Can't wait for the unboxing/teardown/educational video  O0