Here are my guesses. D2: 6.2 zener or tranzorber (protection) diode. C2 looks like a high voltage cap. Is this module connected to some transmission (tele) medium? It would help with a description what this module does and/or where it came from. If IC1 is a serial eeprom, there must be some logic int (or ext) to read/write it. If int, maybe d3 is some tiny cpu, if ext it may be some dual port logic. Or maybe a hall sensor? It looks like the i2c bus (from the L02 chip) is also connected to this chip, so my guess is a sensor or maybe even a unique serial number chip (check dallas, now ti)
The wires seems to be gnd,power,scl and sda.
You could also try
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(google for smdcode)
If you also could remove the white label, we could try to reverse engineer the netlist and get more out of it. I see there is a lot of 51R resistors there..
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.
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.
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.
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.
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.
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.
On Fri, 25 Nov 2011 19:24:11 +1100, Franc Zabkar put finger to keyboard and composed:
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.
On Fri, 25 Nov 2011 11:16:24 +0100, "Pierre-François (f5bqp_pfm)" put finger to keyboard and composed:
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
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