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KK's Propeller Dev system — Parallax Forums

KK's Propeller Dev system

Kaos KiddKaos Kidd Posts: 614
edited 2006-05-16 16:57 in Propeller 1
Well, not being the best at the "grunt work" in development, I'v come to a conclusion and have made progress.
My system is comprised of the following:
  1. ATX PC power supply.· There's an issue with this one.· Apperently you need to put some load on the power supply for it to properly regulate, which I can't find what I need to do to what.· For now, it's outputing 3.0, 5.89, -5.08, 10.80, -7.86 volts on the 3.3,5.0,-5.0,12.0 and -12.o lines.· Not sure what the deal is but I'm working on it.· If anyone has any information on how to do this with an Acer 235w unit, please let me know.
  2. Big bread board with the propeller, 5 Mhz xtal, 32K EEPROM, Power led, USB2SER and reset all wired up as per the same schmatic as the Demo board, excluding the 10K and including the 4.7K pull ups on the EEPROM lines.· With mothers day being the next day I might get to play, it's not going to be until Tuesday night that I get to fully test with BLINK.SPIN.. (All electral contacts have been tested... just the full power on test remains!
  3. Radio shacks small bread board as I/O "cards".· One with VGA, another with Composit, and yet another with PS/2.· In the works is yet another with a Over/Under VGA/duel PS/2 ports.· This way I can develop for what ever I'm using.· Soon (I already ordered the connectors) a new card, SD interface.· My intentions is to create a SD object.
  4. A special bread board with the "Master Servo Controller" wired, and one accompaning "Servo Controller" card, so I can finish the 144 Servo controller.· This board is simular to the main dev board I made, but is specially wired for the project.· Once I prove the work, I'll be ordering PC boards and make it happen.

· With the last thing waiting is to prove and fire up the Propeller, I'm confident the system will work.· If I can get my DC to work long enough to snap a pic or two, I'll add them here.· I just thought I'd share my "objects in code and in hardware" approch with everyone.· Chip said in another thread that the demo board just doesn't do the propeller justice," and I agree.· That is another reason why I went with the modular approch to the I/O boards.· If I don't need it, I just don't include it in the system.

Comments & crits are always welcome!!



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Just tossing my two bits worth into the bit bucket


KK
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Comments

  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-05-15 02:43
    Just an Update...
    IT WORKS!
    Blinkled.spin ran without a hitch...
    Graphics demo ran without a hitch...
    I have a power supply issue, but it is running... I need to get a more reliable power supply...
    I think I'll be duplicating the power supply as described on the demo board...
    Yea Haw!
    More later...

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    Just tossing my two bits worth into the bit bucket


    KK
    ·
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-05-15 05:33
    Have the +5 on that ATX supply draw at least 500ma to stabilize the system - you can call that a ballast resistor.
    I think that requires a 10ohm resistor at 3watts.
    You can do more if you really want to [noparse][[/noparse]like 5ohms at greater than 5 watts], but it is all being turned into heat.

    From what I understand, all the voltages are regulated against the stability of the +5, so you don't have to separately stabilize the 3.3volts or any other.

    With this much amperage available,·be sure to consider FUSING all connects to your Propeller down to about .250amps. The Propeller needs only 200ma tops and if you have an accidental short [noparse][[/noparse]like putting an unprotected board on a metal desk or nest of wires], things will likely burn unless fused.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 5/15/2006 5:39:29 AM GMT
  • kjennejohnkjennejohn Posts: 171
    edited 2006-05-15 05:54
    Try a low wattage 6V motorcycle lamp. This worked great for us in our shop 17, 18 years ago when switching supplies were still bleeding edge technology. We tried doing a 3 day burnin on the first unit with no load and it smoked on the third day. We poked a hole in the side of a small coffee can, ran the supply wires through this hole up through the top, wired it to the lamp with a socket, than just let the lamp sit on the can rim. Worked like a charm.

    It still produces heat, but you get usable light out of it too.
    kenjj
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-05-15 18:52
    Kramer and Kjennejon..
    Thanks! I'll give it a shot tonight...
    Man, I do hope it works... right now, the 3.3 is outputting 2.9, and a few times the propeller when into browout (2.8 or less)...

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    Just tossing my two bits worth into the bit bucket


    KK
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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-05-15 19:53
    Kaos Kidd said...(trimmed)
    1. ATX PC power supply.· There's an issue with this one.· Apperently you need to put some load on the power supply for it to properly regulate, which I can't find what I need to do to what.· For now, it's outputing 3.0, 5.89, -5.08, 10.80, -7.86 volts on the 3.3,5.0,-5.0,12.0 and -12.o lines.· Not sure what the deal is but I'm working on it.· If anyone has any information on how to do this with an Acer 235w unit, please let me know.
    KK,

    ·· In having a computer shop for over 10 years I noticed that the high-end supplies are more stable an include pre-loading on the outputs so they are at the corrcet voltage without any external load.· They often have almost no noise as well.· Cheap power supplies on the other hand can be a real source of trouble.· These often have outputs out of spec even with external loading and lots of noise.· I suspect this may be the case.· Some poewr supplies, such as Sparkle and Antec are really nice.· Of course, when you hold one of these in one hand and a cheaper one in the other you can tell by the weight where the money is.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-05-15 21:11
    Chris, thanks for the info... I've googled and think I might end up getting a Antec SL 250S unit.
    for now, maybe the little tricks I'v been told wil work..

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    Just tossing my two bits worth into the bit bucket


    KK
    ·
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-05-16 15:49
    KK,

    ·· I should've posted this in my last message...I just want to be clear...Without a good scope you have no way of knowing how much noise is on the supply.· One thing you could do if you really want to use one is to implement in your circuit the circuitry (or something close) that is on most motherboards.· This will reduce any incoming noise.· This subject is kind of like automotive power systems in that for the most part the general consensus is that they're extremely noisy.· This isn't always the ase, especially on newer vehicles, however there really is no way to know on a given vehicle without actually testing it, and under different circumstances.· I had one vehicle that seemed electrically noise free until I turned on the fan.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-05-16 16:12
    Thanks Chris.
    (I didn't get a chance to work on my project last night... too many other thinggies going on... Maybe tonight, before Deadliest Catch is on...)

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    Just tossing my two bits worth into the bit bucket


    KK
    ·
  • Michael SchneiderMichael Schneider Posts: 1
    edited 2006-05-16 16:57
    Here is a link on creating a bench power supply from a computer power supply, hope it is useful to you,

    Mike

    http://www.instructables.com/ex/i/D5FC00DAB9B110289B50001143E7E506/?ALLSTEPS
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