Can You Guess Which Micro This Is?

Jul 05, 2008 25 Replies

I just bought a small embedded device (an iPod adapter for a car stereo). Being the inquisitive type, I popped open the case to see what the board inside looked like. I immediately noticed that several of the chips, including the microcontroller, have had their markings removed(!!!) I guess someone doesn't want people to know what sort of parts they're using to make this thing. :)



So of course now I'm *really* curious. :) But I'm not a hardware guy, so I need some help. Anyone care to take a guess as to which micro this might be?



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The oscillator for the micro is there in the foreground - the number on it is ATSO8ASM, and it's made by a company called CTS. I wasn't able to find anything more than that on the web.



Some other clues: the micro is connected to both a CAN interface chip and a J1850 interface chip, and may have built-in controller peripherals for these buses. Also, the red plastic thing on the right side of the photograph is a set of 5 DIP switches, which appear to run directly into some pins on the right hand side of the micro - these could be GPIOs. The six-pin DIP header in the lower left corner of the photograph might be a JTAG connector.



Any guesses?


48 pins QFP is more likely ARM, not AVR. If I want it difficult, first thing is to scramble the header.

What pins are the oscillator connected to ?? What pins are the CAN interface chip connected to ??

Does the CAN chip have a number ??

My first guess. Six pin programmer is likely to be AVR.

donald

I looked up 48-pin tqfp AVR on Digikey, nice search capablity.

AVR does not have OSC pins on 41 and 42. ( look close at the pic the OP posted )

I also looked at a few NXP and the OSC is on pins 8 and 9.

So, it might be custom.

donald

Are you sure that crystal is connected to pins 41 and 42? Since the mark on the case is in the upper left corner I would say that OSC pins are on 21 & 22. I looked at AVR, Luminary, SAM7, PIC, NXP, and found nothing that has oscillator on these pins. Any other ideas? Maybe ST?

_|/ Francesco Sacchi - Develer S.r.l., R&D dept. |\ http://www.develer.com/ - http://www.bertos.org

Sorry, fat fingers. Yes it is 21 and 22.

donald

My multimeter agrees with you.

However, and this may simply be the result of too-big leads on my meter and clumsy probing on my part, but each pin of the oscillator appears to be connected to TWO adjacent pins on the micro: 20+21 and

22+23. I need to find one of those lamps with a magnifying glass in the middle and buy some smaller probes before I can be sure.

In message , donald writes

Or a freescale part Doesn't BDM have 6 pins?

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In message , Scott in SoCal writes

Any other pins you can identify?

Like the pins going to the CAN part, where the DIP switches connect to.

Have you tried looking at the part under a UV light?

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This has OSC pins on 21/22.

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Page 40 is the pin out.

You can check other pin to see if it matches.

It may be in this family, if this part is not a good match.

good luck

donald

How about MC9S12, oscillator pins seem to match and the part also has CAN.

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Henri

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I think the OP stated the CAN chip was off board.

donald

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Actually, I'm not sure where the CAN chip is at this point. There are

5 ICs with their markings obfuscated. One or more of them could be a CAN transceiver.

Yes, that looks like an extremely good candidate.

I'm afraid I'm not well equipped to deal with these fine-pitch surface mount devices. I'm in the process of digging up some decent probes and a nice magnifying lamp. It might be a couple of days before I can trace the pins on the micro with reasonable accuracy.

Stay tuned! :)

I'm afraid I need better tools, but I'm working on getting them.

No - what would that tell me? Might it reveal some trace remnants of the original marking on the obfuscated parts?

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This has been fun.

So, can you please give a little more information about "an iPod adapter for a car stereo".

Maybe another pics of the entire board.

thanks

donald

In message , Scott in SoCal writes

That was my thought.

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It could very well be a six pin BDM header from a freescale HCS12 or (not sure about this) HCS08.

What pins of the header are connected to power or ground? For an HCS12 pin 2 is ground, pin 6 is power, while pins 2 (BDM) and 4 (nreset) go to the chip and should have ~10K pullup resistors on the board. Pins 3 & 5 are probably nc.

It could be Freescale HCS12 (or perhaps HCS08, but not sure about that) BDM connector. For the HCS12, Pin 2 would be ground, pin 6 power. Pins 1 & 4 go to the micro and have maybe 10k pullup resistors.

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