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Discussion in 'Electronic Components' started by Pierre-François (f5bqp_pfm), Nov 23, 2011.

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  1. Hi the Group,

    On the following module (see the picts into the links below) I'm
    searching to identify the following components:

    IC1: L02
    Probably a PIC (?), nevertheless for sure a programmable component.

    D4: 6F

    D3: R12

    D2: 6.2B
    Difficult to read clearly even under the binocular.

    Here are the picts:



    The most important is IC1.

    D3 has six pins, very strange for a rectifier, my smd code book doesn't
    have an "R12".

    Many thanks for your help.
    Pierre-Francois, f5bqp
  2. Piotr Piatek

    Piotr Piatek Guest

    Serial EEPROM with I2C bus, some variant of 24C02, perhaps BR24L02
    npn transistor BC818-25
  3. Le 23/11/2011 07:57, "Pierre-François (f5bqp_pfm)" a écrit :
    Hi the Gang,

    Many thanks for these first replies, I'll continue to investigate, your
    guesses are interesting and bring me on the good direction.
    If any other ideas don't hesitate, you're welcome.

    All the bests and thanks again.
    pf, f5bqp
  4. Le 23/11/2011 15:17, Morten Leikvoll a écrit :

    Hi Morten & the Gang,

    I forgot to answer your question, so here it's:
    This small module is a dongle associates to a DVDROM which contain the
    update of the cartography for a car GPS.

    When you open the motorized screen which flip from 90°, you have on the
    side of the GPS screen a 3.5mm jack socket to plug this dongle.
    then you insert your DVDROM to update the hard-disk of the GPS unit.
    The 3.5mm jack is a 4 pins jack going to the 4 color wires you can see.
    The 3.5mm jack isn't on the picture.

    Hope you understand better the functionality of this small module.
    This is a key, you update once then you cannot update another GPS system...
    The problem is that I'm going to add from time to time some remarkable
    points to the cartography, then I'll update much more than once!
    So I need to find a way to update that dongle.

    Tomorrow I'll remove that white label to do another pict for you.

    All the bests
  5. Franc Zabkar

    Franc Zabkar Guest

    D4 looks like a dual diode with common cathode, or could it be a dual
    zener with common anode ???

    If D3 is some kind of diode array, then your multimeter may be able to
    tell you where the PN junctions are.

    - Franc Zabkar
  6. Le 23/11/2011 11:05, Piotr Piatek a écrit :
    Hi Piotr,

    I've checked the BC818-25 datasheet, they're saying 6Fs for the marking,
    so I don't know.

    Concerning the 24C02 & the BR24L02 these are serious possible
    candidates, however the both datasheet don't mention any marking code so
    I don't know either.
    But it's very probable it's an I2C EEPROM thinking to the function this
    small dongle is doing.

    All the bests.
    pf, f5bqp
  7. Piotr Piatek

    Piotr Piatek Guest

    The marking 6F looked familiar to me, because we use these transistors
    at work, but I think that I was wrong. It's more likely some dual
    diode, as Franc Zabkar suggested.
  8. Le 23/11/2011 15:17, Morten Leikvoll a écrit :


    Here is as promised yesterday night the pict with the white sticker
    removed, we can see that D2 is in // with C2, so D2 could be a transient
    suppressor on to the power lines "just in case"?... Or a Zener at 6.2v
    as you mentioned earlier.

    Another pict showing the 3.5 jack:

  9. Le 24/11/2011 11:25, Piotr Piatek a écrit :
    Hi Piotr,

    No problem, the investigation is continuing... :)

  10. Le 24/11/2011 11:40, Morten Leikvoll a écrit :
    Hi Morten,

    Wouhaa! First time I see such a silicon registering tool!
    Today you make me less crazy than this morning! Thanks for that... ;-)
    Yes and no, because each time you get a new DVDROM you get a new dongle,
    so the serialnumber IC isn't attached to the GPS.

    May be to the DVDROM itself, could be, but the DVD production should be
    a mess in that case...

  11. Hi Again Morten,

    I measured precisely the D3 packaging with a caliper, and it's smaller.
    1.3mm large , 2.0mm Long

    The PIC10F is SOT23 packaging which is 1.3mm large BUT 2.7mm Long.
    On the same side of this tiny board where D3 we're trying to identify is
    you have D4 which is an SOT23 packaging, you can see it's bigger.


    Le 24/11/2011 15:17, Morten Leikvoll a écrit :
  12. Franc Zabkar

    Franc Zabkar Guest

    ISTM that the whole thing may be as simple as a solitary I2C EEPROM.

    I'm guessing D3 is a diode array that protects the clock and data
    inputs from ESD.

    Vcc ---|<|---o---|<|--- Gnd

    SCL / SDA

    I think you're correct in that D2 appears to be a transient voltage
    suppressor (or maybe a zener). Its breakdown voltage is probably 6.2V
    whereas the supply voltage for the EEPROM would be 5V or 3.3V.

    - Franc Zabkar
  13. Franc Zabkar

    Franc Zabkar Guest

    It's not the same part, but it has an R12 marking:

    SR12, RailClamp, Semtech, Low Capacitance TVS Diode Array:

    - Franc Zabkar
  14. Franc Zabkar

    Franc Zabkar Guest

    Try pulling up the EEPROM's Write Protect pin to Vcc. That should
    disable any writes.

    BTW, there is a 51 ohm resistor in series with the Vcc input. This
    would suggest that the current draw of the entire PCB needs to be very
    low. For example, a current draw of 10mA would result in an
    unacceptably high voltage drop of 0.5V. According to the data sheet of
    the BR24L02, the voltage drop across the 51 ohm resistor during write
    mode would be about 60mV. That sounds OK.

    256×8 bit electrically erasable PROM
    BR24L02-W / BR24L02F-W / BR24L02FJ-W
    BR24L02FV-W / BR24L02FVM-W:

    - Single power supply (1.8V to 5.5V)
    - Write (5V) : 1.2mA (Typ.)
    - Read (5V) : 0.2mA (Typ.)

    - Franc Zabkar
  15. Le 25/11/2011 09:29, Franc Zabkar a écrit :
    Hi Franc,

    The Semtech could be a good candidate for the function, however it has
    only 4 pins, D3 has 6, and D3 is much more tiny, the Semtech is SOT143
    2.8mm long .

  16. Franc Zabkar

    Franc Zabkar Guest

    That's why I wrote that "it's not the same part". Nevertheless I
    suspect your part would have a similar function. In any case, what is
    preventing you from performing a simple test with a multimeter? AISI
    the circuit is essentially just an EEPROM on a stick and should not
    require much effort to "reverse engineer".

    - Franc Zabkar
  17. Franc Zabkar

    Franc Zabkar Guest

    Here is my best guess as to your circuit layout:

    Vcc 51R 51R
    ___ Vcc1 ___ Vcc2
    Red (4) o-|___|--+---+-----|___|---+--------> to EEPROM pin #8
    R1 | | R2 |
    | | |
    | | D2 |
    --- z ---
    C2 --- A 6.2B --- C3
    | | |
    R10 | | R11 |
    ___ | | ___ |
    Blk (2) o-|___|--+---+-----|___|---+--------> to EEPROM pin #4
    51R Gnd1 51R Gnd2

    SDA 51R ^ 51R
    ___ D3-A| ___
    Yel (1) o-|___|--------+--------|___|----+---+------> EEPROM pin #5
    R8 | R4 | |
    - - ---
    ^ D4-A ^ --- C5
    | | |
    | --+--
    -+- |
    Gnd1 -+-

    SCL 51R ^ 51R
    ___ D3-B| ___
    Blu (3) o-|___|--------+--------|___|----+---+------> EEPROM pin #6
    R7 | R3 | |
    - - ---
    ^ D4-B ^ --- C4
    | | |
    | --+--
    -+- |
    Gnd1 -+-

    | | | |
    | | R5| |R6
    .-. | .-. .-.
    1K | | R9 | | | | | 2K2
    | | | | | | |
    '-' .-------V-------. | '-' '-'
    | | | | | |
    -----| 1 A0 Vcc 8 |--- | |
    | | | |
    .--| 2 A1 WP 7 |--. | |
    | | | | | |
    |--| 3 A2 SCL 6 |--)---'----)------> to D3-B via R3
    | | | | |
    |--| 4 Gnd SDA 5 |--)--------'------> to D3-A via R4
    | '---------------' |
    | BR24L02 |
    | +--'-+
    | | |
    | .-. |
    | R12 | | --- C1
    | 10K | | ---
    | '-' |
    | | |

    (created by AACircuit v1.28.6 beta 04/19/05

    I suspect that the pinout of D3 is as follows:

    D D
    pin2 ---|<|---o---|<|--- pin1 D3-A

    D D
    pin5 ---|<|---o---|<|--- pin4 D3-B

    I confess that I don't understand the purpose of D4.

    - Franc Zabkar
  18. Le 26/11/2011 11:58, Franc Zabkar a écrit :
    Hi Franc,

    Back to home after two days outside I'll look at that, thanks for your
    work, I appreciate very much.

    All the bests.
  19. Le 25/11/2011 21:06, Franc Zabkar a écrit :
    Yes I'm going to do it.

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