Post Reply 
 
Thread Rating:
  • 1 Vote(s) - 5 Average
  • 1
  • 2
  • 3
  • 4
  • 5
oscilloscope demo example
02-03-2014, 05:44 PM (This post was last modified: 02-03-2014 05:45 PM by Fleasystems.)
Post: #1
oscilloscope demo example
Hello again Smile

I have been working on a new demo example for FleaFPGA. After a few experiments with analog signal processing, I managed to create a simple oscilloscope demo! Big Grin

FleaFPGA with analog input board installed:
[Image: Analog_in_FleaFPGA_small.jpg]

Capturing the output waveform of a 4MHz crystal:
[Image: FleaFPGA_DSO_4MHz_xtal_small.jpg]

Examining a VGA Horizontal Sync Signal:
[Image: FleaFPGA_DSO_VGA_HSync_pulse_small.jpg]

More to follow..

Regards,
Valentin Angelovski
Find all posts by this user
Quote this message in a reply
03-26-2014, 01:36 AM
Post: #2
RE: oscilloscope demo example
(02-03-2014 05:44 PM)Fleasystems Wrote:  Hello again Smile

I have been working on a new demo example for FleaFPGA. After a few experiments with analog signal processing, I managed to create a simple oscilloscope demo! Big Grin

FleaFPGA with analog input board installed:
[Image: Analog_in_FleaFPGA_small.jpg]

Capturing the output waveform of a 4MHz crystal:
[Image: FleaFPGA_DSO_4MHz_xtal_small.jpg]

Examining a VGA Horizontal Sync Signal:
[Image: FleaFPGA_DSO_VGA_HSync_pulse_small.jpg]

More to follow..

Regards,
Valentin Angelovski

What does the Analog input board consist of ? Is it just an RC circuit or is there an ADC chip?
Find all posts by this user
Quote this message in a reply
03-26-2014, 04:20 PM
Post: #3
RE: oscilloscope demo example
(03-26-2014 01:36 AM)TimMcD0n41d Wrote:  What does the Analog input board consist of ? Is it just an RC circuit or is there an ADC chip?

Hello Tim,

Thanks for your question. The Analog input board contains little more than a few passive parts and (rather obviously) a BNC connector. Nearly all of the analog-to-digital conversion happens inside the FPGA.

I hope to get back to this little side-project again after the FleaFPGA production run.

Regards Valentin
Find all posts by this user
Quote this message in a reply
06-02-2014, 07:55 PM (This post was last modified: 06-23-2014 08:04 PM by Fleasystems.)
Post: #4
RE: oscilloscope demo example
Hello again!

I am happy to announce that I have a preliminary version of my 'Fleascope' Digital Oscilloscope example working with the following features:

1.) Adjustable waveform trigger level (-ve edge trigger)
2.) Adjustable timebase from 2msec/Div down to ~490nsec/Div
3.) Bandwidth ~10MHz and resolution from 6 to 5 bits depending on the timebase setting.
4.) Takes up 7% of the MachXO2 inside FleaFPGA!

Here are a few screenshots of the fleasope v0.1 in action:
Note: First three waveforms are set at 500Hz, while the last waveform exercises a higher-end of the scope by testing a 921KBaud UART signal TX out (streaming continuous 'U' characters..)

[Image: Fleascope_CRO_Sine_small.jpg]
[Image: Fleascope_CRO_Sawtooth_small.jpg]
[Image: Fleascope_CRO_Square_Zoom_small.jpg]
[Image: Fleascope_CRO_UART_921KBaud_small.jpg]
[Image: Fleascope_Sine_small.jpg]
[Image: Fleascope_Sawtooth_small.jpg]
[Image: Fleascope_Square_Zoom_small.jpg]
[Image: Fleascope_UART_921KBaud_small.jpg]

For FleaFPGA users who are interested in trying this example out, I have compiled a zipped bitfile and schematic for you to download and try. I will hopefully release the sources to this example as soon as I have tidied them up.

Further details are in the included readme.txt file. Happy Experimenting! Smile

Regards Valentin
Find all posts by this user
Quote this message in a reply
06-23-2014, 08:02 PM (This post was last modified: 06-25-2014 03:22 PM by Fleasystems.)
Post: #5
RE: oscilloscope demo example
Dear all,

(06-02-2014 07:55 PM)Fleasystems Wrote:  I will hopefully release the sources to this example as soon as I have tidied them up.

Done! Smile VHDL source for my Digital Oscilloscope example may be downloaded from here. Please refer to the included readme and schematic PDF files for details.

Those of you wanting to know more about sigma-delta ADC on FPGA, there are several online references. Here is one of them.

Alternatively if you only want to try out the FleaDSO example, you can download the latest schematics and FPGA bit-file for your FleaFPGA board.

Happy experimenting! Smile

Regards Valentin
Find all posts by this user
Quote this message in a reply
06-25-2014, 03:22 PM (This post was last modified: 06-25-2014 03:22 PM by Fleasystems.)
Post: #6
RE: oscilloscope demo example
Oops! I somehow uploaded slow sample-clock version of the VHDL source Sad Please try the download links again to get the (intended) fast version. Thanks!
Find all posts by this user
Quote this message in a reply
Post Reply 


Forum Jump:


User(s) browsing this thread: 1 Guest(s)

Contact Us | Your Website | Return to Top | Return to Content | Lite (Archive) Mode | RSS Syndication