Computer Hope
Hardware => Hardware => Topic started by: NickMMM on November 05, 2013, 05:45:33 PM
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Hi,
I am looking to buy (or have custom made) a USB Flash Drive<12 units, at first> at any capacity, preferably more than 512MB, that has a crystal oscillator. This would be versus a silicon oscillator. An even better benefit would be an oscillator with low jitter, I assume this would be a 'higher quality' oscillator. Any and all help would be greatly appreciated.
Thanks,
Nick
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Well, you could make your own. What frequency you need?
This forum has a policy about strange hardware and software used to victimize other people. What you describe, a USB device with an non-board Oscillator , is often used by spies to taker data form a Vitim's computer.
Photo:
(http://www.bing.com/th?id=H.4506697503672468&pid=3.1&w=300&h=300&p=0)
Would you like to explain what you have in mind?
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You may have just murdered the english language....that being said, if I was looking to steal or victimize anyone, I could do that. That's easy & practical. What I need is not a separate oscillator. I just need a flash drive with a crystal oscillator versus a silicon one that seem to frequent almost every single new flash drive.
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My problem is spelling. ;D And typing. And I can't find my dictation software.
Crystal oscillators on a USB are sold as 'clandestine ' devices.
Again, what frequency do you need? And what kind of oscillator does the common Flash drive normally have? And why would it make a difference? What measurements have your made on a flash chip that leads you to think thee is a stability issue? Are you waiting to build a time base device?
Pardon me, but In just don't understand. If you want precision time, the PC already does that for you. Do you need a portable frequency standard?
What may seem to be instability in a flesh drive is not the clock rate. It has to do with the quality and speed of the device and the thermal limits. Writing tends to heat up a flash device and is slower than a read. It is not a change in clock, rather the write cycles are longer. By design. Using a crystal would not change that.
So, what do you want to do?
This link is for users who have some engineering experience.
http://www.ftdichip.com/Support/Documents/AppNotes/AN_100_Using_The_FT232_245R_With_External_Osc%28FT_000067%29.pdf
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What I am looking to do is very unconventional, it's a counter-intuitive process we are using them for. In a conventional approach, I don't think you would see a difference between silicon or crystal. With this it matters. Quite the rare item now-a-days, so it seems... traditional flash drives have an oscillator that clocks at 12.000 Mhz
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OK. Got the idea. (The OP is talking about a 12 MHz quartz crystal. )
(http://thumbs1.ebaystatic.com/m/mB8B65uekL6r5SwhdWYddFQ/140.jpg)
The free running oscillators are used in many devices where high precision is not needed. The accuracy is usually inside of 2%, wheres a crystal can stay inside of a 0.005 % range and are often used for clocks and frequency counters as will as RF transmitters. I suppose you don't want a RF transmitter.
You may be able to order it custom made. but that is a rather rare item. Look over the data sheets for the flash chips and see if there is ab option of locking the internal oscillator to a crystal. Most crystals, in my own experiments, will lock a free-running circuit, even when lightly coupled through a small capacitor. Look for a circuit where the internal oscillator has an external pin for a frequency-setting capacitor.
This page claims many drives have a crystal.
http://www.bestelectronicarticles.com/computers/usb/how-to-repair-usb-flash-drive.html
As does this one
http://www.durofy.com/inside-the-usb-pen-drive/
Is this of any help?
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I'm actually looking for a link to buy one.
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I'm actually looking for a link to buy one.
Apparently some come with crystal. Some maybe you have to call the vendor to find out what they want to sell you.
BTW a quartz crystal can be fragile. Bang it hard and it stops working. That might explain why some drives fail after awhile.
http://www.flashbay.com/support/faq/flash-drives-review
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I fail to see the actual point of this thread. What would the type of crystal used in the drive have to do with anything?
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I fail to see the actual point of this thread. What would the type of crystal used in the drive have to do with anything?
I asked the OP that already. He was vague in his reply.
FYI very cheap USB devices do not use a quartz crystal. This can cause tinning errors which could make the device less reliable in some applications. But the OP never made this clear. So I have to guess.
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The trouble you have is it's optional to use an oscillator or crystal in a pen drive and most manufactures need to keep costs down so op not to use either and stick with the silicon circuit instead.
I suggest you purchase several older designed pen drives , if you can find old stock from 5 years or older you will have a better chance of finding what you want.
The only pen drive I could find here with an oscillator was a legend 512mb thats 6 years old.
We also have all the current pen drive PCB's and none have the option of a crystal or oscillator.
So to get what you are looking for you would need to have a run made using old PCB's and for 10 that would be at least $100.00 each.
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Lisa_maree,
a run of 10 or 12 would be perfect, is this something you can do?
Thanks!
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or am I able to buy 10-12 of those legend flash drives?
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The trouble you have is it's optional to use an oscillator or crystal in a pen drive and most manufactures need to keep costs down so op not to use either and stick .... you would need to have a run made using old PCB's and for 10 that would be at least $100.00 each.
Lisa_maree, are you making wild guess? I think I could find about 50 of them for about $12 each. They are not so rare. Yet.
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I cracked open a Trend Micro 4Gb stick the one day to touch up on a cold solder joint and it still had the 12mhz crystal in it. Look for one in clear plastic to see what you are getting the one I have is in clear red plastic.
This Reader has the 12mhz crystal as you can see thru the clear plastic and you can turn it into a USB Flash Drive... other actual flash drives exist with clear plastic to see the internals without gambling on if crystal or not. http://www.ebay.com/itm/USB-SD-Clear-Card-Reader-Writes-Reads-SD-SDHC-Turn-a-SD-Card-into-a-flash-drive-/221308911237?pt=AU_Digital_Memory_Card_Readers_Adaptors&hash=item338709fe85#ht_792wt_1133 (http://www.ebay.com/itm/USB-SD-Clear-Card-Reader-Writes-Reads-SD-SDHC-Turn-a-SD-Card-into-a-flash-drive-/221308911237?pt=AU_Digital_Memory_Card_Readers_Adaptors&hash=item338709fe85#ht_792wt_1133)
This one here may also have a crystal in it. I'd contact the seller to have them take a picture for you with the thumb drive folded out to see thru the clear plastic to the PCB and verify that a crystal is present. http://www.ebay.com/itm/8GB-Swivel-Metal-USB2-0-Flash-Drive-Memory-Stick-Thumb-Ricco-01-001-CLEAR-PURPLE-/130844029782?pt=UK_Computing_FlashDrives_SM&hash=item1e76e97356#ht_2847wt_896 (http://www.ebay.com/itm/8GB-Swivel-Metal-USB2-0-Flash-Drive-Memory-Stick-Thumb-Ricco-01-001-CLEAR-PURPLE-/130844029782?pt=UK_Computing_FlashDrives_SM&hash=item1e76e97356#ht_2847wt_896)
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was that TrendMicro purchased recently? And from where?
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Do a Google, this guy has posted in lots of forums.
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Yes, because clearly I am in need of help, how is that relevant or helpful?
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We don't understand your objective.
You can get older models of USB drives from vendors who sell in lots Some of these have crystals instead of the newer designs. Yu could just buy a few and tear them open and find out how they are made. At least one major vendor claims they even has crystals non the new models. So why have you no called them on an 800 number and talk to them?
In general, this forum is to help individuals with personal computer issues, not to help commercial users locate the lowest price on legacy hardware.
To put it another way, we enjoy helping people, but not to the point of doing their work for them. We would like to know if this topic would be helpful to other uses, just just a firm that has made a secret discovery about use of a legacy item.
Perhaps you company has discovered that crystal oscillators help keep insects out of a computer. If so, share it will the rest of us.
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Salmon said it best...
It's been posted on many Forums...and the OP is extremely vague on what exactly he wants...
Other than that you guys are spinnin your wheels for no apparent reason...