Identifing EPROMS

Discussion in 'General Electronics Chat' started by Joster, Nov 11, 2013.

  1. Joster

    Thread Starter Member

    Jun 12, 2013
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    Hi All!



    Wondering if anyone out there can help me identify these old eproms. I tried google but didn't have much luck,



    Thanks!



    Joster
     
  2. JohnInTX

    Moderator

    Jun 26, 2012
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    Hard to say but if indeed they are memories, they are probably 27Cxxx EPROM dies in an opaque package so they are program-once (OTP). Way back when, that was a cheaper way to get programmable memory than the same die in a ceramic/window package. They could also be a masked part. The number is likely a pattern number for a programmed chip.

    There isn't any way of erasing them so.. not a whole lot of value there.

    I'm guessing that if they were flash or electrically erasable, they would likely have a real PN on them.
     
  3. Joster

    Thread Starter Member

    Jun 12, 2013
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    aha! Thank you! Makes sense now why they only have a 4 digit number..no manufacturer number or anything. They are just one time programmed memory chips.

    As a side note: I going to be buying an Eprom programmer. I was wondering if any old universal programmer will work? Or can it get somewhat specific. I'll be programming 1Meg flash chips

    Cheers
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Many of the programmers available cover all the common Eproms.
    I picked one up from ebay some years ago which covers most.
    Including the UV erasable.
    Max.
     
  5. JohnInTX

    Moderator

    Jun 26, 2012
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    A buddy of mine just found one of these at Fry's for cheap. Works fine. You'll find that 'universal' programmers are more expensive than 'PROM' programmers (because they use many pin-drivers) but the difference can be worth it if you expect to use various memories.

    One caveat; "Universal" programmers can be temperamental when programming microcontrollers. The uCHIP parts in the device list are pretty old, pre-ISCP stuff.

    I personally would also avoid the cheapo-Chinese stuff.

    Good luck!
     
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    Is that recess at the top a window that never was? You could try to carefully open one and see if you make them erasable (UV). Who knows.
     
  7. rogs

    Active Member

    Aug 28, 2009
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    If it's for the flash in your other kick drum thread, then I bought one of these for my prototype for that project:

    http://www.amazon.com/G540-Universal-Eprom-Flash-Programmer/dp/B00EQ2PE90/ref=pd_sxp_f_pt

    Works fine with flash. Comes with a PLCC to 32 pin dip adaptor. Recommend you use a 32 DIP ZIF in your prototype board - especially if you're using stripboard. That way you can just plug your flash into the ZIF with the adaptor.

    If you are making a pcb, than you'd obviously only use the PLCC holder, but I would suggest you make a stripboard prototype first.
    For example, the circuit i posted in the other thread works OK, but I've already changed it bit, to help with the stripboard layout
     
  8. ScottWang

    Moderator

    Aug 23, 2012
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    I bought a second hand to use, it was made in China, cheap, but the operation method is unnormal, many chips will be putting at the different direction and weird position, if you want to buy it then you should get use to it.
     
  9. rogs

    Active Member

    Aug 28, 2009
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    Yes, mine too..

    that's why I bought it...I only need to programme a few Flash chips, so an expensive 'industrial ' quality unit was not really needed for that task.....cheap was good for this job...

    I didn't find that ... if you put the chips in the position indicated on the top of the unit, they work fine. Obviously, if the unit can cope with 28, 32 and 40 pin chips, then some pins will remain unconnected with the smaller devices.
    Instructions are quite clear on my unit....
     
  10. ScottWang

    Moderator

    Aug 23, 2012
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    Long time ago that I was worked for a company, they was designing that kind of the programmer, but all of the ICs are putting the same direction, my job was to design a computer system to test the programmer is good or bad.

    Putting all the ICs at the same direction will make the user easy to use, all the common pin is the 20 pin.
     
  11. rogs

    Active Member

    Aug 28, 2009
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    All the ICs are inserted the same direction on the programmer I suggested above.. so no problems there
     
  12. ScottWang

    Moderator

    Aug 23, 2012
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    As AT89S52 and Winbond W27C512 are the same direction, but no common pin.

    Pic16F690 - the direction is different, it have to be putting at the middle position.

    Whatever the G840 or G540 are designed to the same way, I'm not sure are they care about the patent problem or some other else.

    So if you just using a few kinds of ICs, maybe you won't meet like that.
     
  13. rogs

    Active Member

    Aug 28, 2009
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    I must confess I haven't looked at the pin configurations for all 6500+ devices this programmer can supposedly handle.
    I was looking for a cheap unit to program EPROMs and FLASH chips, and at a price of £32 ( about $50) it seems like pretty good value for doing just that.
    And the orientation for those devices seems logical (and as illustrated on the unit)
    Maybe there are better choices for programming PIC devices?..... that's not really what I was looking for though.......
     
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