Digital oscilloscope Project

[martingn]

oscilloscope jyetech

Hi people,

These are some of my thoughs :

- I agree about the benefits of a handheld DSO. I would prefer that kind but in a second stage.
- I dont think that galvanic isolation is a must.
- Any method imlemented to link DSO with PC is always slower that conversion rate so, lets keep it simple.
- If we are looking for a cheap project, I think that we have to give a chance to the FPGA to do it all. That will be a nice chanlenge for us!
- Why dont we slit the whole project so we can go ahead and build the diferent parts. This is my proposal:
Board 1 : input + amp + ADC
Board 2 : FPGA + IO + User Interface
Board 3 : Supply

ME,
EP1K10 is the only FPGA available in local market here. Do you think it could fit ?

Thanks all your your interest !
Best regards,

MArtin

 

[martingn]

ads831 dso

Cant find Protel DXP for download!!! Any suggestion?
regards,
MArtin

 

[davorin]

low cost digital oscilloscope

You can go to:

www.altium.com/protel/evaluation/request.asp

and request an evaluation CD...

 

[ME]

logic scope avr

Cant find P*otel DXP for download!!! Any suggestion?
regards,
MArtin

Protel DXP have changed name to Protel 2004.

Protel 2004 = Protel DXP + SP3 for DXP + some other features.

SP1 for Protel 2004 can be downloaded here:
www.@ltium.com/downloads/files/DXP2004ServicePack1.exe

Replace '@' with 'a'

 

[monnoliv]

digital oscilloscope pcmcia project

Hi all,
Very interesting discussions. Let me presents the possibles solutions that I see for the DSO:

Solution 1: Hand held DSO
Advantages:
- No insulation needed between a PC
- Stand alone (great)
- Downloading data to a PC possible with a serial interface (USB, RS232)
Disadvantages:
- µC needed to have a good display behavior
- FPGA with a configuration memory (no download from a PC at each power on!), ex EPC2 from Altera: +- 25€
- Display (what is the price ?)

Solution 2: PC based DSO 1 (no uC)
Advantages:
- one "intelligent device" FPGA
- Smaller PCB -> smaller price
Disadvantages:
- FPGA with a configuration memory (since no µC for download conf)
- No insulation possible (I never seen a USB isolation scheme, low cost)
- Bigger FPGA, bigger price
- PC needed
- huge FPGA development


Solution 3: PC based DSO 2 (with uC)
Advantages:
- All devices can be configured via USB port
- insulation possible between USB device and uC (or at outputs of µC if USB integrated in it)
- Smaller FPGA
Disadvantages:
- more components, PCB bigger
- PC needed
- Price higher than Solution 2

Ok, let us find a agreement, just keep in mind the limitations of each solution.
If you find other configurations possibles, write them here to discuss.

Personnaly, I prefer the first one,

regards,

 

[ME]

fpga projects oscilloscope

ME,
EP1K10 is the only FPGA available in local market here. Do you think it could fit ?

Sorry I'm only a not very experienced with FPGA's and VHDL, so I can't say if EP1K10 is big enough for a DSO.
Maybe some of the more experienced FPGA users can give a qulified estimation of the speed and size needs.
I nobody answers it in this topic, you can try to ask the question in the FPGA forum, where all the experts are.

 

[ME]

jyetech code

Solution 1: Hand held DSO
Advantages:
- No insulation needed between a PC
- Stand alone (great)
- Downloading data to a PC possible with a serial interface (USB, RS232)
Disadvantages:
- µC needed to have a good display behavior
- FPGA with a configuration memory (no download from a PC at each power on!), ex EPC2 from @ltera: +- 25€
- Display (what is the price ?)

Why do you need a µC for good dispaly behavior? You can do this with a FPGA.

Why not download the configuration memory from the PC via RS232, USB or parallel port to JTAG interface at each DSO power on?

CPLDs doesn't need to be configured at each power up, are CPLDs too slow or small for this project or why does it need to be an FPGA?
Are CPLDs with external FIFO more expensive than an FPGA with internal RAM and external configuration memory?

Solution 2: PC based DSO 1 (no uC)
Advantages:
- one "intelligent device" FPGA
- Smaller PCB -> smaller price
Disadvantages:
- FPGA with a configuration memory (since no µC for download conf)
- No insulation possible (I never seen a USB isolation scheme, low cost)
- Bigger FPGA, bigger price
- PC needed
- huge FPGA development

If you are afraid of huge FPGA development you can just implement a ready-made µC IP-core in a part of the FPGA.
The IP-core could be based on 8051 or another coomon architecture.
Then you can program the IP-core part of the FPGA in C os assembly like a normal µC.

You can get a lot of free µC IP-cores for both Verilog and VHDL to implemetn in an FPGA or CPLD here:
https://www.opencores.org/browse.cgi/by_category

You can also find free IP-cores for FireWire, USB, Ethernet, Graphical LCD interfaces etc. at Opencores.

 

[ME]

digital oscilloscope schema

- FPGA with a configuration memory (no download from a PC at each power on!), ex EPC2 from @ltera: +- 25€

You can get 'drop-in replacement' configuration memories from other vendors.
Atmel AT17LV002A for example is a 'drop-in replacement' for Altera EPC2:
http://www.atmel.com/dyn/products/product_card.asp?part_id=2530
This or other compatible configuration memories might be cheaper than the 'original' from Altera.

Prices at www.EBV.com
Altera EPC2LC20 costs €24.96 (Minimum Pack Quantity: 49)
Atmel AT17LV002A costs €10.15 (Minimum Pack Quantity: 50)

This is a huge saving only by replacing one IC with a pin-compatible IC from another vendor.

 

[davorin]

fpga + oscilloscope project

Well...designing now a DSO/Analyzer as well...though host is an old Applce Mac SE/30...so I already have power/display and interfaces to outside ... and even gives a "LeCroy" feeling (o:

For the core of DSO/analyzer I choosed Altera Cyclone devices and use built-in RAM for storing samples and control the ADC...

And confiuration memories fo them are quite cheap...2 - 3 US$ for an EPCS1..and you even get samples for them as also Cyclone FPGAs itself (o;

 

[martingn]

digital oscilloscope 3.

Hi all,

Davorin do you have any project already developed with Cyclone ?

REgards,
Martin

 

[davorin]

oscilloscope usb project

Regarding DSO? No.

Only made a 2-layer PCB with EP1C3 running original PacMan game (o;

 

[martingn]

how to build a digital oscilloscope

Hi all,

I would suggest develop a little "prototype" first.
FPGA core, PC based, RS-232 comms, downolad cfg with cable, no uC, single channel, single board.

I will help us to learn FPGA stuff in an easy board.

Suggestions?

regards,
MArtin

 

[davorin]

pdamusician.com project

I would rather suggest using an old VGA monitor hooked up to FPGA...there are tons of application notes about this..and it is only a few lines of code.

This way you save time on spending writing code on PC software (or get started with it ;o). Also the design is then totally indepedant.

And also for a start do not use an ADC first hand...capture raw digital inputs as in a logic analyzer and direct output to VGA monitor...or use those fancy in-circuit ChipScope/whatever-it-is-called to see how things work internally.

Start at the core of your problem..do not waste writing Visual-Whatever-crap-language code on Windows PCs (o;

 

[martingn]

adc microcontroller oscillo

Hi ME,

I dont know what LabVIEW is.
Lets keep all simple for prototype. If this soft helps to do it, Welcome.

I'm thinking about the prototype specifications. What tasks should the "proto" at least perform?

regards,
MArtin

 

[ME]

wireless oscilloscope

Hi all,

I would suggest develop a little "prototype" first.
FPGA core, PC based, RS-232 comms, downolad cfg with cable, no uC, single channel, single board.

I will help us to learn FPGA stuff in an easy board.

Suggestions?

regards,
MArtin

Sound like a good idea Martin

What about PC software?
Should it be made in LabVIEW or should it be a stand-alone software?
Maybe it is easiests to make it in LabVIEW first?
Or maybe Davorin's suggestion is the best.

I think a lot of the hardware in BitScope 300 can be reused, for example some of the analog circuits, instead of inventing the wheel again.
There is hardware schematics at https://www.bitscope.com/design/

I was wondering if there is any particulary reason why only Altera is mentioned as choiche for the FPGA / CPLD? Is it cheaper than the other big company Xilinx, or is it because it is possible to order free samples or is it a 3rd reason?

 

[davorin]

project pc oscilloscope

1. Do you need external fast SRAM? Mostly it is enough to use internal faster RAM blocks in FPGA...use phase-shifted clock to double the rate to 500MSamples/sec or more.

2. Lot´s of pin headers (o; Making it possible to hook-up easily any ADC you like.

3. VGA/PS2/RS232 port and of course power supply (o;

4. ISP (JTAG) connector or serial config eeprom

For a start quite enough...or if you can get a hand on a cheap FPGA eval board..do it!

 

[ME]

oscilloscope analog front-end schematic

Hi ME,

I dont know what LabVIEW is.
Lets keep all simple for prototype. If this soft helps to do it, Welcome

LabVIEW is a great EDA tool from National Instruments.
It reminds a bit similar of Simulink for Matlab, if you know Simulink?
But LabVIEW is more graphical oriented and advanced.
It is a kind of graphical programming tool for measurement and control.
LabVIEW is even embedded in some new fancy top stand alone DSOs.

Look here: https://www.ni.com/labview/

LabVIEW for Dummiees: **broken link removed**

 

[ME]

fpga oscilloscope high speed 16 channel

For a start quite enough...or if you can get a hand on a cheap FPGA eval board..do it!

Here is a big list of FPGA eval boards from different vendors and 3rd party companies, prices are listed too.
The list is updated regulary (Last updated 06/04/2004)
www.fpga-faq.com/FPGA_Boards.shtml

See Also:
Die FPGA-Kochecke: www.aufzu.de/FPGA/boards.html
Another list of boards: http://dmoz.org/Computers/Hardware/Programmable_Logic/FPGA/Boards/
Xilinx's list of boards: www.xilinx.com/xlnx/xil_prodcat_product.jsp?title=protoboards_protoboards_page
Altera's list of boards: www.altera.com/products/devkits/kit-dev_platforms.jsp
Altera's list of Partner Development Kits: www.altera.com/products/devkits/kit-dev_platforms_partner.html
Optimagic's list of boards: www.optimagic.com/boards.html

 

[martingn]

fltk oscilloscope

Davorin,

I think that use a VGA connected to the DSO will not be practical for the following reasons:
-not everybody has 2 monitors.
-the final project will be a handheld.
I think that a capture of the sampled data will be easy to be managed in a PC. (it just to check not final interface)

Not to use an ADC at first step could be a good idea. May be we can implement 2 boards. FPGA board and Input board.

Me,

I dont have acces to samples here in my country and the only one that I could find here is altera EP1K10TC144. I would suggest to use that if everybody agree.
Altera ACEX 1K starting at U$10 , Cyclone starting at U$20 (arrow)
Personally I never read any info of Xilinx FPGA.

regards,
MArtin

 

[davorin]

oscilloscope front-end

I think that use a VGA connected to the DSO will not be practical for the following reasons:
-not everybody has 2 monitors.
-the final project will be a handheld.
I think that a capture of the sampled data will be easy to be managed in a PC. (it just to check not final interface)

Who needs 2 monitors? (o;

The question was for a "quick start"...and the easiest way to visualize something from FPGA is via VGA...doesn't matter if the final design supports an external monitor or uses a link to PC where someone spends endless hours to write some OS-centric capture software (o;

Hmm US$20 is quite expensive...I got EP1C3T100 samples for free (o;
If you can wait some few months you can grab those Spartan-3 devices from Xilinx...