Struggling understanding EEPROMS - 24C04 & 24C04-6

Discussion in 'General Electronics Chat' started by wogboy_9000, Nov 8, 2009.

  1. wogboy_9000

    Thread Starter New Member

    Nov 8, 2009
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    Hello everyone, I've been lingering around looking for a while, but this is my first post.

    I've bought an EEPROM programmer and software to go with it. I'm not sure how to use it, but I'm sure I'll figure it out.

    My question is, I have an EEPROM on a circuit board that is a SOP8 ST 24C04-6 that I want to copy and change the data on... I'm scared I'll stuff it up, so I want to buy a couple other EEPROM chips to experiment with once I've copied the data. If I buy some 24C04 chips, are they the same thing as the 24C04-6?

    I'm just confused as to whether there is no difference, and the '6' at the end is just a ST MICROELECTRONICS' thing, or whether there is an actual difference.

    Greatly appreciated.
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    the -6 looks like it's temperature rating. I wouldn't be to worried about 'stuffing it up'. If you have programming software, do a read and file save. Just watch your device orientation.
     
  3. wogboy_9000

    Thread Starter New Member

    Nov 8, 2009
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    Thanks for the quick response! If its a temperature rating, then it shouldn't be too much of an issue?

    So are all 24C04 chips pretty much the same and interchangeable (besides differences like SOP8)?
    I'm just worried about buying the wrong chips, as there seem to be a few types/brands... But if they are all the same I'll just any :)

    Thanks again.
     
  4. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    Spec sheets are readily available, and you should do a quick compare. Some devices may have write protect pinned. Your programmer compatibility list should also be referred to .
     
  5. wogboy_9000

    Thread Starter New Member

    Nov 8, 2009
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    Okay, so I've bought an eeprom programmer, but the chip looks to be too small and fiddly to be removed from the board without breaking it, and I'm going to struggle to solder it back on correctly.

    Is it possible to piggyback it from the board to the programmer?
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Trying to reprogram the mileage in a car speedometer are we?? ;)
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    Probably not since the programmer has to power the board or be faced with fighting the other chips on the board for access to the Serial EEPROM. We used to call it CMOS butt humping when two outputs are connected together trying to control the same input. Tends not to work very well.

    Yeah, the price of a surface mount rework station is a real bear. Not to mention the investment in time to develop the requisite skills. Things were easier in the days of vacuum tubes and point to point wiring.
     
  8. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    Post a photo of the EEPROM & PCB
     
  9. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    Depends on the port configuration of the device that accessess the eeprom in your cicuit, as well as your ability to render that device inactive. It could be as simple as maintaining a reset, but you need to investigate that.

    Are you truly knowledged to the data structure in the memory? Data dumps rarely have any meaning unless you are intimately familiar with the structure.
     
  10. wogboy_9000

    Thread Starter New Member

    Nov 8, 2009
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    Yep. Some glitch has occurred, and the mileage started again at 0, which isn't ideal, and it looks dodgy. I need to get it back to 100,000-ish miles like it was before. The mileage is also recorded in the ECU, so changing the mileage to something other than what it should be isn't something I'd do, and it would be very easy to find the true mileage.

    I've got a mileage calculator program to tell me what the data should be on the EEPROM for the correct mileage, so I'm roughly familiar with the data and structure.

    I'll take a photo of the board when I get a chance in the next day or two.

    Another thing, I bought a new 24C04 Chip, and it is the same size as the one on the board, however it is too small for the programmer I bought. All the programmers I have seen have the same size plug for the EEPROM.

    This is the one I have, and my chip is too small for it...
    http://cgi.ebay.com.au/24Cxx-93Cxx-...upplies_ET?hash=item48386e62b3#ht_2363wt_1167

    How do I get around this problem?
     
  11. wogboy_9000

    Thread Starter New Member

    Nov 8, 2009
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    Anyone with any ideas how to fit the chip to the programmer? :)
     
  12. wogboy_9000

    Thread Starter New Member

    Nov 8, 2009
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    anyone? :)
     
  13. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    People may be reluctant to help someone who *might* be trying to break the law.
     
  14. ftsolutions

    Active Member

    Nov 21, 2009
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    That board looks like it is designed to accept DIP package parts - you've probably got the surface mount SOIC8 pin variety. You'll have to make up an adapter ..
     
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