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can the wrong crystal even if it is 5MHZ ruin a PROP? — Parallax Forums

can the wrong crystal even if it is 5MHZ ruin a PROP?

codevipercodeviper Posts: 208
edited 2012-04-07 03:33 in General Discussion
ok my DEMO board was stocked with an NES port PSkeyboard port an NTSD LCD ran off of 6 NICADs or 4 NiZn AAs and had a 5MHZ crystal.
i built it to the demoboard schematics and had 100ohm resisters between the prop and the NES port. and an SD card
my first PROP died last month after light use.
well i tested everything else. and when i got my new prop i happened to get 2 new 5MHZ crystals.
i had a problem with my programs needing a 2000HZ adjustment and the examples from some hydra code never showing color right.
well i noticed the old crystals had 5.00-S the new ones 5.00-20 (as in 20pf i belive wich i did make sure they where to begin with.
with the new crystals all code works as normal.
so is it possible the old crystals were responsible for ruining my PROP?
cause i always look for a why did this happen.
honestly i dont feel like playing this game.
i did not plug AC into my board.
i did not nor cannot put the voltage in backwards.
it did not get put in an oven or freezer.
nor hit by a hammer
it did not get AC in on it.
it did not bet out in acid set on fire nor struck by the hand of god.
i followed the reference circuit and now i am told, they assumed the builder knew what he is doing. i have 2 problems with that.
1:it is an insult
2: i have seen lots of reference circuits for chips with a capacitor when the chip is noise sensitive, and i have chips that are spicificly made to NOT be noise sensitive.
I see a video of the prop being baked in a climate chamber and ruining great.under the socket for my prop i have 2 wires crossed to the connecting Vss to Vss and Vdd to Vdd so i need 1 capacitor then right?
I only picked the PROP cause i read these forums and all things i did was following the manual and Jeff ledgers book on things you can put on the proto-board.

Comments

  • LeonLeon Posts: 7,620
    edited 2012-04-04 20:47
    The "wrong" crystal won't cause any damage.
  • Mike GreenMike Green Posts: 23,101
    edited 2012-04-04 20:48
    No. Old crystals cannot ruin a Propeller. A crystal is manufactured to function with a particular capacitance value in parallel or in series with the crystal. If it's put into a circuit with the wrong capacitance, the crystal will be off in frequency, but usually it will work otherwise. Worse come to worst, the crystal won't oscillate at all (like if the capacitance is way too high), but that would be unusual.
  • codevipercodeviper Posts: 208
    edited 2012-04-04 21:40
    did not mean old really just using old in the sense i already had it. and used it, the new ones work perfectly.
    this is weirding me out, i got to figure out why the old PROP died and in a list i was trying to make everyone seemed to basicly be saying the PROP couldent be killed by anything i thought killed mine.
    can it be i just got a bad PROP? or should i try the old prop with the new crystals?
    is there a return on PROPs i dont think there would be.
    cause according to my meter the voltage is good the power is clean according to my O-scope and i have added resistors to almost any IO like to the NES controller even though i was powering the NES controller off of 3.3V. so my head is throbbing over it.
    every thing is right, everything has been double checked. so what killed my propeller.
    :blank:
    its driving me ever so slightly up a wall. :lol:
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-04-04 21:51
    The most typical way for a Propeller to "die" is for the PLL to Smile out due to inadequate bypassing, poor Vdd/Vss routing, or not connecting all of the Vdd/Vss pins.

    -Phil
  • Mike GreenMike Green Posts: 23,101
    edited 2012-04-04 22:00
    To elaborate ... There are multiple Vdd / Vss pins on the chip to help distribute the supply current around the chip. The supply connections on the chip are thin aluminum films that have some resistance. If you connect all the Vdd / Vss pins to printed circuit board traces carrying power and ground and have bypass capacitors across each Vdd / Vss pair, the voltages across the chip will be fairly close to the supply voltage provided. If you leave out some of these connections and bypassing, there will be voltage drops across the chip, particularly when noise is present on the supply lines. These voltage drops can get large enough to damage some of the structures on the chip and the PLL selector is the most vulnerable area for some reason. Typically, the Propeller Tool can download a program to RAM or EEPROM, but the program won't run if it uses the crystal and PLL.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-04-05 04:36
    Just out of curiousity.... If you short the two crystal pins together, will that kill a Propeller? If so, that might be the source of the failure.
  • LeonLeon Posts: 7,620
    edited 2012-04-05 04:42
    On-chip crystal oscillators are usually of the Pierce variety:

    http://www.abracon.com/Support/facn_abracon_jul2011.pdf

    Shorting the pins shouldn't cause any damage.
  • codevipercodeviper Posts: 208
    edited 2012-04-05 05:27
    i am curious. if the lack of a capacitor is so dangerous, why is it the basic circuit for the DIP in the manual lacks capacitors, and why is it in the demoboard REV G there is only 1 1uf capacitor if all VDD and VSS's need their own capacitors. if they need them i will add them from now on, but it will be great if the manuals and demoboard schematics are revised as i took their layouts literally.
    as far as safety is concerned, i even but a full bridge rectifier on my board so i can plug in any AC adapter so long as it is between 6 to 12 volts and the jack fits :smile:
  • skylightskylight Posts: 1,915
    edited 2012-04-05 05:45
    I'm presuming that the quickstart board doesn't suffer from this lack of capacitor issue and you won't damage the prop following the tutorials?
  • LeonLeon Posts: 7,620
    edited 2012-04-05 06:31
    codeviper wrote: »
    i am curious. if the lack of a capacitor is so dangerous, why is it the basic circuit for the DIP in the manual lacks capacitors, and why is it in the demoboard REV G there is only 1 1uf capacitor if all VDD and VSS's need their own capacitors. if they need them i will add them from now on, but it will be great if the manuals and demoboard schematics are revised as i took their layouts literally.
    as far as safety is concerned, i even but a full bridge rectifier on my board so i can plug in any AC adapter so long as it is between 6 to 12 volts and the jack fits :smile:

    They probably assumed that designers know what they are doing. :)

    On the Demo board, they probably assumed that their particular layout worked OK with a single capacitor. IIRC, there are copper pour areas which help with the decoupling. However, I always use one capacitor per Vdd-Vss pair.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-04-05 08:55
    codeviper wrote:
    i even but a full bridge rectifier on my board so i can plug in any AC adapter so long as it is between 6 to 12 volts and the jack fits
    You realize, of course, that a 12 VAC transformer is going to give you about 17 VDC after rectification, right? Also, to avoid 60 Hz ripple, you need a very large filter cap (> 2200 uF) post-rectification.

    -Phil
  • idbruceidbruce Posts: 6,197
    edited 2012-04-05 09:11
    codeviper

    I am curious. Why would you want to be able to hook up a 12VAC transformer, when AC adapters are readily available?

    Additionally, you used wrong terminology, as Phil and I both corrected you. An AC adapter converts alternating current to direct current, and if you are transforming a higher voltage to a lower voltage, you would be using a step down transformer, even though they may look physically identical, they are not the same.

    Bruce
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-04-05 09:18
    idbruce wrote:
    An AC adapter converts alternating current to direct current,
    Not always. There are plug-in wall warts that output AC, and they're still called "AC adapters," even though they consist of nothing more than a transformer. The ones you really have to watch out for are adapters designed as battery chargers. They nominally produce DC, but it's often unfiltered, requiring a large external cap to eliminate the ripple.

    -Phil
  • idbruceidbruce Posts: 6,197
    edited 2012-04-05 09:23
    they're still called "AC adapters

    I am not sure where I found the documentation, but from what I read, that is technically incorrect.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-04-05 09:29
    Strict technical correctness and common usage are two different things, of course. Besides, an adapter can be anything that converts its input to something different on the output, so simply stepping down the voltage without transforming it to DC should qualify. Then there are those things called "adapters" that let you run your 110 VAC electric razor on 220 VAC abroad, and which are probably just autotransformers.

    -Phil
  • idbruceidbruce Posts: 6,197
    edited 2012-04-05 09:30
    Phil - However, a search at Mouser, lists both under AC adapters. So I will admit defeat :)

    Sorry codeviper, when going from AC to AC, it may still be called an AC adapter, but theoretically it is just a step down transformer.
  • codevipercodeviper Posts: 208
    edited 2012-04-05 09:41
    I have chips that in the reference design they say
    "this device is noise sensitive, do not omit __ uf capaciter between Vdd Vss."

    and seeing as the prop is so easy to program and setup the prop as a novice can get it going on a bread-board, perhaps it would be both convenient, and kind to novices or people like myself who assumed the schematic included all pertinent data to mention that when building your own board include ____ uf capacitors.
    to me it seemed logical seeing as the propeller was described here as being super tough, and there is a video of the parallax crew baking it at temps high enough to shift the crystal requiring the Prop to be ran off an external clock (here is the link http://www.youtube.com/watch?v=EjkXokgcBZw)
    so i assumed after reading posts here and watching the demos that it was tough rugged chip.
    may i point out that a 6502 is used an medical equipment and military gear as it can survive an EMP wave that say a defibrillator makes. and there are some chips that are noise immune.
    If it is sensitive to noise, cool, i will add capacitors now.
    a mention of capacitors could be made on schematics for the demo-board, and also i noticed that the serial to prop circuit in the manual does not work but the one posted on its own works perfectly, I tried both circuits, and yes i tried on both a built in serial and a USB to RS232.
    one question, can i get a new prop if a send this one in? test it if you want i didn't plug power in backwards or anything like that.
    but i felt so lousy when it died cause I thought I had done something wrong and I have been searching and searching for the why it died.
  • codevipercodeviper Posts: 208
    edited 2012-04-05 09:47
    idbruce wrote: »
    Phil - However, a search at Mouser, lists both under AC adapters. So I will admit defeat :)

    Sorry codeviper, when going from AC to AC, it may still be called an AC adapter, but theoretically it is just a step down transformer.
    I use AC to DC adapters. BUT i have adapters with different polarities on their connectors. do with the rectifier i don't have to worry about inverse voltage in the connector.
    like i have 2 9 volt adapters one has a +center and -outer the other is opposite, with the rectifier i don't have to worry which i grab.
  • codevipercodeviper Posts: 208
    edited 2012-04-05 09:55
    it seems you guys grabed the wrong end of the stick.
    i do use an AC to DC adapter. commonly in my area it is just called an AC adapter.
    i am using the rectifier so i dont have to car about the polarity of the connector.
  • kwinnkwinn Posts: 8,697
    edited 2012-04-05 21:52
    @codeviper

    I think your idea of using a bridge rectifier on the power in is a good idea, particularly on the boards used for prototyping. I also use a bridge rectifier or at least a single diode wherever possible on my boards. The protection provided is well worth the cost.

    As for what may have gone wrong with your prop board, I can come up with more possible causes than I have time to list. To list them would be moot in any case since it would be very difficult to determine the actual cause without a lot of test equipment. What you may want to do is to start with the simplest setup possible (prop, recommended bypass capacitors, 3.3V supply, and programming plug) to see if it is found by the Propeller Tool. If it is found you can proceed to find out what works and what doesn't. If not there is no point in worrying about it.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-04-06 01:34
    LOL - It seems right to me. An AC adapter would adapt AC to DC. An AC transformer would NOT. But there always are such pitfalls in techinical terminology. I have a great deal of difficulty with understanding the British at times and THEY seem to be more serious about teaching their version of English to the world.

    Rectifiers and diodes are great protection against wrong hook up if you can afford the voltage drop.
  • LeonLeon Posts: 7,620
    edited 2012-04-06 03:09
    I've always understood AC adapter to mean something that can output either low-voltage AC or DC. An AC-DC or AC/DC adapter would denote the conventional "wall-wart" with DC output (regulated or non-regulated).
  • codevipercodeviper Posts: 208
    edited 2012-04-06 10:58
    kwinn wrote: »
    @codeviper

    I think your idea of using a bridge rectifier on the power in is a good idea, particularly on the boards used for prototyping. I also use a bridge rectifier or at least a single diode wherever possible on my boards. The protection provided is well worth the cost.

    As for what may have gone wrong with your prop board, I can come up with more possible causes than I have time to list. To list them would be moot in any case since it would be very difficult to determine the actual cause without a lot of test equipment. What you may want to do is to start with the simplest setup possible (prop, recommended bypass capacitors, 3.3V supply, and programming plug) to see if it is found by the Propeller Tool. If it is found you can proceed to find out what works and what doesn't. If not there is no point in worrying about it.
    thanks that acknowledgement is exactly what i needed.
    Loopy Byteloose

    thanks, i know a few Brits and the ones I know personally are nice. i asked one of them about that, and it seems in Britain that behavior seems less exceptible so it seems some of them are taking it out on the internet. :lol:
    i always say "you can make freinds or you can make sure everyone knows your way is right"

    Leon
    In my area NO one says wall wart, and will look at someone oddly if they did. they are just AC adapter, if I may mention the Super Nintendo had some units with a 9 volt AC "walwart" transformer, wallwart seems to refer to the clunky cubes hanging off the wall not what they actually do, but just the appearance.
  • idbruceidbruce Posts: 6,197
    edited 2012-04-06 12:30
    OKAY OKAY

    What do I have to do?

    Walk around with a great BIG sign saying I WAS WRONG :):)
  • Mike GreenMike Green Posts: 23,101
    edited 2012-04-06 12:42
    Using a great BIG sign can be cathartic at times. Feel free to indulge. Sometimes "thanks for the info" is useful. Often wearing big floppy shoes, a green or blue wig, and a matching ping-pong or rubber ball on your nose can endear you to clumps of small children ... useful at times.
  • codevipercodeviper Posts: 208
    edited 2012-04-06 13:27
    idbruce wrote: »
    OKAY OKAY

    What do I have to do?

    Walk around with a great BIG sign saying I WAS WRONG :):)
    sorry i didnt mean that directed at you
    you are very helpful.
  • idbruceidbruce Posts: 6,197
    edited 2012-04-06 13:32
    codeviper

    Don't worry about it, there was no offense taken :) I was just laughing a little at myself :) Besides, I don't mind being wrong, just as long as I am right 99.999999999% of the time. :)

    Just joking... I am often WRONG :)

    Bruce
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2012-04-07 03:33
    Nobody is wrong, it is just lingustics. Meaning really requires negotiation and confirmation, but we seem to presume our audience has the same linguistic knowledge that we do. The really good and popular writers are able to reach a wide audience (like Agatha Christie), but technical material is highly problematic and less and less material is published about standard meaning and so on.

    The best one can do is to NOT rely on technical language, but try to confirm your idea is as low a level of common language as you can. The average American usage in published material is 10-grade English, not even close to a university graduate level.

    Here in Taiwan, I have no idea what they call these things in Chinese or Hakka or Taiwanese, I just grab one off the shelf. When I ask for something in English - like a relay; eye glaze over.

    But the REAL truth is name variations occur in distances as little as 100 miles or so. To one person, a nail puller might be a cat's paw, to another a crow's foot, and so on. So negotiate and confirm.
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