If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #333
Joined: Mon Mar 20 2006, 06:02PM
Location: Czech Republic
Posts: 45
Steve Conner wrote ...
Yes, I believe Steve Ward and Phillip Slawinski's latest driver is a digital PLL running on some sort of fast microcontroller, and a few people are working on FPGA-based drivers at the moment.
A MCU has too much latency to run anything but a PLL, but a FPGA can emulate a traditional feedback driver too, possibly using digital filters for phase lead.
Yeah, I already seen in another thread that they made some FPGA PLL design with fast ADC. I think FPGAs are very well suited for this purpose but they are still a bit blackbox for me. I would rather use some DSP which also have quite low latency and high throughput (due to multiple buses and special instructiuon) but they are expansive. But now there are many low cost and fast enough ARM MCUs that maybe also could handle it. So maybe for som future project...
Registered Member #2292
Joined: Fri Aug 14 2009, 05:33PM
Location: The Wild West AKA Arizona
Posts: 795
The cool thing about FPGAs is that they are not as much of a black box as you may thing! I learned VHDL in about a month not spending a whole lot of time. The thing that makes FPGA based design much better than MCU is not only the speed (100MHz+) but the parallel processing capability.
Let’s say you had an MCU that reads an ADC and then updates a timer based on that info, this may take many clocks (hundreds even) because the MCU can only do one thing at a time. First it would read the ADC then it would update the timer with a lot of little steps in between. With the FPGA this whole operation could be done potential in one clock cycle if coded correctly. On top of this it could also be doing several other things at the same time, like receiving serial data, all without impacting any other part of the device.
If anything I would say it simply takes a shift in thinking from traditional MCUs to program any kind of programmable logic. Although the code is c-like it functions a lot differently due to the parallel operation.
My FPGA based control uses a pipe line ADC running at the same speed as the FPGA. Basically every clock (100MHz) the ADC clocks 10 bits of data into the FPGA via a parallel pipeline interafce. One clock later the output changes as a direct result. That’s roughly a 20nS response time to any change in conduction. This is as fast as most analog units doing the same thing.
Registered Member #333
Joined: Mon Mar 20 2006, 06:02PM
Location: Czech Republic
Posts: 45
Goodchild wrote ...
The cool thing about FPGAs is that they are not as much of a black box as you may thing! I learned VHDL in about a month not spending a whole lot of time. The thing that makes FPGA based design much better than MCU is not only the speed (100MHz+) but the parallel processing capability...
Yes. I didn't express well. The principles of FPGA, PLD, PLA... are known to me a quite long (I met them on university a little bit). I understand what advantages/disadvantages over MCU it has, you're right. But mostly I have a problem with thinking in parallel programming and VHDL. And there are some cathes like e.g. signal propagation issue in long counter structure and other limitations that don't exist in MCU world (MCU's has surely its different cathes :). Also I didn't saw there would be available some simple lightweight opensource/free developing environment like equivalent of GNU GCC tool chain that is widely spreaded over MCUs. I only saw that manufacturers are giving some demoversion of their bloatware limited to small designs. I also never physically programmed the FPGA and don't know what kind of programmer I need. I like e.g. programming of Atmel AVR MCUs because I just need 5 wires from my parallel port to do SPI programming. Yeah I admit that's all due to my laziness but I didn't get the right motivation to study and use FPGAs more at work or elsewhere yet, and free time is very limited as I'm working now...
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
PLL SSTC with Type 2 phase comparator problems (added some info)
