46
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Messages - riktw
47
Project logs / Re: Simple Altera CPLD breakoutboards
i bookmarked the site, good to remember :)
48
Project logs / Re: Simple Altera CPLD breakoutboards
adding the internal crystal/PLL was easy, haven't used the 1K flash memory yet.
only downside i that they are not 5V compatible as far as i know.
thanks for that link sqkybeaver :)
so is a http://creativecommons.org/licenses/by/3.0/ for this project :)
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Project logs / Simple Altera CPLD breakoutboards
i made a couple CPLD breakoutboards using the new MAX V series of CPLD's from altera.
the MAX V series got some fun functions like 1K flash, a crystal and PLL internal.
i used the 5M80Z, 2 dollars each and 80 logic elements
Pictures, each 600kb:
http://img233.imageshack.us/img233/6500/dsc02160ym.jpg
http://img819.imageshack.us/img819/8191/dsc02161o.jpg
yes i am out of flux and yes i hand soldered those 0.4mm IC's WITH ground plane on the bottom :)
i got another 2 with all pinheaders installed.
becouse these CPLD's are just 2 dollars i made some extra.
and ofcourse the eagle files: http://www.uploadarchief.net/files/down ... 0board.zip
you can use it for whatever you want, to lazy to find out what freeware license that is ;)
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Project logs / Re: USB Scope
i already made a fully working 4 bit ALU in Schematic entry mode so a scope is a new challenge.
with 570 logic cells i can add a fair amount of counters etc etc for SRAM control so i think it should work out fine.
i used the FT2232H before and i find it quite easy to use when i need lots of speed.
i made some documentation for school for it but i am afraid its in dutch, so posting it here wont be really helpful for most of you ;)
going to make a PCB for it tomorrow so i can connect an ADC to the FT2232H, parts will arrive monday i think.
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Project logs / USB Scope
this project wont be done next week, nor even next month.
its a summer holiday project so i will seriously start with it after 4 juli when my 7 weeks of nothingness begins :D
i hope its OK to post a not done project, i will add stuff while making it so i end up with a good log of the whole project.
I want to make a USB scope, but you could have guessed that from the title.
I also want to make it quite cheap, I aim for 50 euro's to make one
as a school project we are already making a simple scope but its rather limited in speed and use, 1Msps is kinda slow :)
but we got the scope part working, only the software is left to do.
but 1Msps is really not useful, effective bandwidth for looking at a sine wave is maybe 50Khz.
Then i saw the scope project from DP(Dangerous Prototypes)
That looks a lot better, 50Msps means 3 to 5 MHz usefulness bandwidth for looking at sine waves.
But then its single channel, uses a Xilinx FPGA and a Picmicro for USB transfer.
Single channel is an easy fix, add another ADC.
I personally work with altera CPLD's so i wont use a Xilinx device and i will use a CPLD and not a FPGA.
As a CPLD is a lot smaller then a FPGA i will need to have a separate SRAM IC for buffering.
Not a real problem, 64 or 128K ram is less then 5 euro's, even 10nS speed SRAM.
I never used a Picmicro for USB transfer, i only used 16F 8 bits Picmicro's until now.
I have used FTDI devices before, the normal FT232 but also the very fast FT2232H so USB transfer is not a problem.
I have some good experience with high speed analog design, tip for DP, even a 1pf capacity between the inputs of the ADC and the ground can be troublesome.
So removing a piece of the ground plane underneath the inputs of the ADC can help a lot for analog performance :)
All with all, in theory i should be able to make a scope, only the PC software is a bit hard for me.
The whole project will be open source so if someone else can help with the software it would be awesome.
Until now I only have design ideas on paper.
When my summer holiday starts I want to have a PCB design done so I can give Iteadstudio something to do :)
Design ideas:
2 ADC's, ADS830@ 50Mhz
2 speedy op-amps, TI has some nice ones for a low price
1 SRAM Buffer, 64KByte, at least 10ns speed
1 CPLD, EPM570 from altera, fast enough and because the SRAM is a separate IC its is probably big enough.
A CPLD doesn’t need a SRAM IC to load code from so CPLD + SRAM is a bit cheaper then an FPGA.
1 FT232 in bitbang mode for a max of 12Mbit USB transfer speed.
I could use a FT2232H but that one is double the price of a FT232
A better 5V and -5V power supply than the USB ones.
And thatch about it :)
Buffer chaos
well I need a buffer, 2 ADC's at 50Mhz create a 100MByte per sec dataflow and its madness to send that trough USB.
I normally get 10 to 12MByte with a FT2232H, 100Mbyte is USB3 range and roughly impossible to do as a student.
I will use a FT232R in bitbang mode, 4 I/O for data and 4 for handshaking/setting trigger/other stuff
at 12Mbit I will have ~750Kbyte per sec with 4 I/O ports.
With a 64K buffer it means I can send it trough USB more then 10 times per second.
Enough, not going to mess with that :)
but 64K buffer means 32K per channel.
At 50Mhz that’s just 640uS of data, seems really tiny right?
Now image you are looking at a 1Mhz sine-wave signal, one sine-wave is then 1uS
you can fit 640 whole sines in that buffer, more then enough it seems
now imagine looking at a 1Khz signal, that’s 1mS for one sine-wave
Now you can't even fit one sine-wave in the buffer, that’s bad!
The solution is simple, you can lower the speed of the ADC or lower the speed that the buffer saves the data.
Both solutions do the same, making the ADC run 100 times slower or just saving one in every 100 samples to the buffer, both ideas slow the whole thing down by 100 times.
When everything is slowed down 100 times you can fit 64mS in the 32K buffer, a lot better.
Then 1Khz isn’t a problem anymore.
Like I said in the top of this slightly to long post, this wont be done in a month.
I want to have it done in begin august when school starts again.
The whole project will be open source and if it actually works and people want it I might poke seeedstudio about selling them.
That’s it for today, when I have more info about anything related to this project I will make another massive post ;)
I will try to connect a ADS830 to a FT2232H directly next week, ADS @ 6 to 10Mhz so I don’t need any form of a buffer and see what happens.
Ideas, please share them :)
Rik
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General discussion / 99 dollar PCI-E FPGA kit
a big PCB with a big FPGA and a fast PCI-E connection for just 99 dollars.
after some googeling i found the quickstart PDF from it, it looks like good value for money but not for beginners.
so if you ever had the urge to develop your own video card or network card, well today's your lucky day :)
Quick start:
http://www.latticesemi.com/documents/QS013.pdf
Lattice site:
http://www.latticesemi.com/products/dev ... entkit.cfm
in the user guide is a big picture of the dev kit, anyone else see a FT2232 for USB programming ;)
well, who's the first to make a lattice programmer :)
http://www.latticesemi.com/documents/EB62.pdf
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General discussion / Re: PCB design software
got a free limited version, got lots of tutorials, multiplatform even.
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General discussion / Problem using FT2232 drivers
i got a problem installing the FTDI drivers with a FT2232H device.
i am using a mini module from FTDI on windows 7 home prem ium (cant spell it right, forum thinks it spam) 64 bits.
when i plug in the device windows automatically installs the usb composite
device driver.
if i update the drivers to the FTDI drivers windows states the composite
device driver is newer and wont install the FTDI drivers.
when i uninstall the composite device driver windows automatically
reinstalls them!
MProg doesnt work with the composite drivers, really annoying.
we kinda need the FT2232 to work for our school project (making a USB scope) so if anyone knows a solution it would be great.
Rik
//edit//
ok, new problem, the whole board seems dead.
my PC running windows ultimate doesnt detect anything.
time to send it back to farnell :(
//edit//