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Sawnoff Propeller "stacked die" ("LopProp") — Parallax Forums

Sawnoff Propeller "stacked die" ("LopProp")

TubularTubular Posts: 4,706
edited 2012-08-30 13:13 in Propeller 1
Since stacked dies are all the rage...

I don't think this would be too hard to construct,with some superglue and a hacksaw. Both eeprom and uSD would be superglued upside down...

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Sawnoff.jpg
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Comments

  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2012-08-29 16:25
    Don't think it, do it! Where there's a mill, there's a way. Then we will all have something to smile about when you show us the photo (and it works) :)

    BTW, I guess Jeff will be your first customer. The only problem is that you will have to sell the chips at half price!
  • TubularTubular Posts: 4,706
    edited 2012-08-29 17:06
    A mill? Sounds a bit high tech. Hacksaw and chisel and hammer and vice... good old garage tech

    Spot the error? Yeah that would be the wrong pin groups I started attacking. I suspect (hope) it will still work fine.
    2012-08-30 09.51.39.jpg
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  • mindrobotsmindrobots Posts: 6,506
    edited 2012-08-29 17:55
    OUCH! Your R&D costs may have just taken a $8US hit!!

    I was wondering how you were picking up the connection to the removed pins (never having hacked into a chip before), now it's clearly obvious!!
  • Clock LoopClock Loop Posts: 2,069
    edited 2012-08-29 23:52
    Whats on the OTHER side of the Prop? Can both sides be hacked off?

    Oh wait, you did that in the image above. So then yes... it looks.

    Both sides hacked off looks almost exactly the same size as smt prop.
  • TubularTubular Posts: 4,706
    edited 2012-08-30 00:16
    mindrobots wrote: »
    OUCH! Your R&D costs may have just taken a $8US hit!!

    I was wondering how you were picking up the connection to the removed pins (never having hacked into a chip before), now it's clearly obvious!!

    It's nice solder friendly copper inside !

    Yes, the budget takes another hit. I think this is the third one committed to scientific exploration. I'm testing that karma theory...
  • TubularTubular Posts: 4,706
    edited 2012-08-30 00:19
    Clock Loop wrote: »
    Whats on the OTHER side of the Prop? Can both sides be hacked off?

    Oh wait, you did that in the image above. So then yes... it looks.

    Both sides hacked off looks almost exactly the same size as smt prop.

    Yes both sides could be hacked, since the die is 7.3mm square, so it fits inside of those middle 4/8 pins (Vss,Boen, Reset, Vdd etc). You could do a 12 pin hack with 1 GPIO pin in each corner, but you'd need to expose some of the top 4 pins to get it booted.

    If you hacked both sides it might be better to go for a QFN (9 or 10mm square from memory)
  • Duane C. JohnsonDuane C. Johnson Posts: 955
    edited 2012-08-30 04:56
    Tubular wrote: »
    Yes both sides could be hacked, since the die is 7.3mm square, so it fits inside of those middle 4/8 pins (Vss,Boen, Reset, Vdd etc).
    Ok, 7.3mm is about "3 Pin" widths.

    But in reality, I would think, the die takes a bit more room because of the "Bond Wires". These go between the die and the pin frames.

    Duane J
  • Heater.Heater. Posts: 21,230
    edited 2012-08-30 05:15
    Stop this already. It's barbaric and monstrous and cruel and and ...I don't have words.
  • PaulPaul Posts: 263
    edited 2012-08-30 09:15
    With all this hacking and chopping, won't the end result be a QFN? What am I missing?
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2012-08-30 09:59
    Heater. wrote: »
    Stop this already. It's barbaric and monstrous and cruel and and ...I don't have words.

    Neither does the Prop. The nibbling has left only nibbles.

    I have super glued SPI flash onto AVRs before, and got close to using SD cards but always wanted to be able to remove it for checking/programming. I have seen a version of this using bent paper clips. I should of done some experiments on my "9 Volt test" one rather than just singing durges until the early morn.

    Perhaps a uSD slot could be molded into the top sheet of plastic
  • Duane C. JohnsonDuane C. Johnson Posts: 955
    edited 2012-08-30 10:12
    I have made many experimental Prop controllers using Plug Boards. Generally, this requires the use of DIP packaged Props.

    Usually I don't need all 32 I/O pins. It would be nice to have a shorter Prop to conserve space, especially on the short Plug Boards.

    Personally, I will try this on one of my props.
    However, I will chop off only 12 pins so I can still insert the SD-Card from P22 to P25 which results in a DIP-28 package instead of a DIP-24.

    Sure, if you are making a PC board it only makes sense to use the smaller package. But I'm an experimenter so the DIP versions work for me.

    Duane J
  • TubularTubular Posts: 4,706
    edited 2012-08-30 12:27
    Duane C. Johnson wrote: »
    Ok, 7.3mm is about "3 Pin" widths.

    But in reality, I would think, the die takes a bit more room because of the "Bond Wires". These go between the die and the pin frames.

    Duane J

    I think the bond wires must be quite compact. The QFN package must have bond wires too, and its 9x9mm external, so still within the "4 pins" (10.16mm) boundary. Actually the exposed pad on the QFN is virtually the same size as the die.
    qfn.png
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  • TubularTubular Posts: 4,706
    edited 2012-08-30 12:37
    Paul wrote: »
    With all this hacking and chopping, won't the end result be a QFN? What am I missing?

    Yes but it'll be a QFN with pins. How user friendly is that?
  • Clock LoopClock Loop Posts: 2,069
    edited 2012-08-30 13:13
    Heater. wrote: »
    Stop this already. It's barbaric and monstrous and cruel and and ...I don't have words.

    Give me all your money, or the prop gets it. Could this be a new money making venture?
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